Does Every Genuine Philosophy Have a Skeptical Side?
Michael N. Forster
As some readers may already know, I have spent a number of years now mining Hegel’s
writings for insights into skepticism. Among those that I have identified and broadly
endorsed, the following three perhaps stand out in importance: (1) Hegel argues
convincingly that ancient skepticism and modern skepticism are sharply different in
character (ancient skepticism being typified by the “equipollence” method, modern
skepticism by the “veil of perception” problem), and that as a result ancient skepticism is
philosophically superior to modern, in particular because free of an essential dogmatism,
and resulting vulnerability to skepticism, which afflict the latter.1 (2) Hegel argues, in
opposition to Kant and other people influenced by him such as G.E. Schulze, who
conceive ancient skepticism as limited in the scope of its attack, that ancient skepticism is
on the contrary a radical position which attacks virtually all beliefs. This interpretive
dispute has recently been replayed by Myles Burnyeat and Michael Frede respectively. I
have argued that it is the radical Hegel-Burnyeat reading of ancient skepticism rather than
1
See my Hegel and Skepticism (Cambridge, Mass.: Harvard University Press, 1989) and
“Hegel on the Superiority of Ancient over Modern Skepticism,” in Skeptizismus und
spekulatives Denken in der Philosophie Hegels, ed. H.F. Fulda and R.-P. Horstmann
(Stuttgart: Klett-Cotta, 1996).
the moderate Kant-Frede reading that is more exegetically correct.2 (3) Hegel argues,
again in opposition to Kant and others influenced by him, that such a radical form of
ancient skepticism is moreover philosophically viable. In particular, he argues that it can
viably attack even judgments of subjective experience and logical principles. I have
argued that on this point too Hegel is correct.3
In this article I would like to identify and defend a fourth important Hegelian insight
into skepticism: the thesis he articulates in his seminal 1802 essay The Relation of
Skepticism to Philosophy that every genuine philosophy has a skeptical side – or, as he
puts it, “that skepticism itself is most intimately one with every true philosophy . . . that a
true philosophy necessarily itself . . . has a negative side.”4
*
In order to appropriate and defend this Hegelian thesis, I will first need to clarify and
disambiguate it in certain ways, though. In particular, the following three points should
be noted.
First, Hegel’s thesis in his 1802 essay is often concerned with “true philosophy” in the
very narrow sense of “philosophy that is true” – which would restrict the bearing of the
thesis to just his own philosophy and a few alleged anticipations thereof by favored
predecessors such as Plato. On the other hand, in the very context of the remarks that I
See my “Hegelian vs. Kantian Interpretations of Pyrrhonism: Revolution or Reaction?”
Kritisches Jahrbuch der Philosophie, 10 (2005).
3
See my Hegel and Skepticism, ch. 1 and Kant and Skepticism (Princeton: Princeton
University Press, 2008), ch. 12.
4
G.W.F. Hegel, Werke, ed. E. Moldenhauer and K.M. Michel (Frankfurt am Main:
Suhrkamp, 1970), 2:227.
2
just quoted, Hegel rejects the idea that philosophy should be equated with dogmatism and
implies that it also includes a broad range of skeptically minded thinkers, among them
not only Plato but also certain poets, Zeno, Xenophanes, and Democritus.5 And at other
points in the essay he identifies Pyrrho and the older set of Pyrrhonian tropes as examples
of philosophy too.6 So there are also good textual grounds for construing “true
philosophy” in his thesis in the broader sense, not of “philosophy that is true,” but of
something more like “genuine philosophy” (whether true or not). While the former,
narrow sense of his thesis is undeniably present in the essay, I find it philosophically
unattractive, and shall therefore simply set it aside here. It is the latter, broad sense of the
thesis that seems to me to have good prospects of being correct, and which interests me
here.
Second, somewhat surprisingly, Hegel in the 1802 essay identifies as the paradigm of
“skepticism” the second half of Plato’s Parmenides – which Hegel interprets as a
destructive dialectic both preparatory and integral to Plato’s positive philosophy (very
much as Hegel’s own destructively dialectical Logic was at this period of his career both
preparatory and integral to his own positive philosophy). However, as I already
mentioned, Hegel in the essay also credits a much broader range of skeptically minded
thinkers as representatives of “skepticism,” including Zeno, Xenophanes, Democritus,
and especially the Pyrrhonists. In short, he often seems ready to count as “skepticism”
virtually any systematic negative intellectual assault on received beliefs or claims to
5
6
Ibid., 227.
Ibid., 238 ff.
knowledge.7 I shall not here be interested in Hegel’s thesis insofar as it concerns only
“skepticism” in the narrow sense of a Platonic-Hegelian destructive dialectic. Nor, for
that matter, shall I be interested in it insofar as it concerns only “skepticism” in the much
less idiosyncratically narrow sense of Pyrrhonism, or Pyrrhonism and Academic
skepticism. Rather, I shall be interested in it insofar as it concerns “skepticism” in the
broader sense that I just attributed to Hegel (which includes, but is not restricted to,
Platonic-Hegelian dialectic, Pyrrhonism, and Academic skepticism). If one prefers to use
an alternative name for this broader range of positions one might perhaps call them
subversive epistemologies.
Third, concerning Plato’s role as the star example that Hegel adduces in support of his
thesis: I think that he is actually a good example, but not necessarily in quite the way that
Hegel supposes. Hegel reads the second half of Plato’s Parmenides as a systematic
dialectical destruction of pre-philosophical presuppositions which leads to a monistic
Platonic philosophical standpoint (very much on the model of Hegel’s own early Logic
and its relation to his own monistic philosophy). That this is the real character of Plato’s
Parmenides is quite questionable, however. Nonetheless, Hegel’s more generic idea that
Plato’s philosophical standpoint was largely a response to skepticism (qua subversive
epistemology) remains very plausible indeed. Recall, for example, the account that Plato
puts in the mouth of his philosophical representative Socrates in the Phaedo, where
Socrates explains his recourse to the theory of forms in terms of the need to avoid the
common “misology” of supposing that equally convincing arguments can be supplied on
I include the word “negative” here in order to distinguish the sort of assault on received
beliefs or claims to knowledge in question from, for example, natural scientific assaults
on them, i.e. assaults that occur as mere by-products of the development of a positive
counter-theory.
7
both sides of any issue and that everything is in flux, and in terms of the need to find a
solution to the demoralizing impact that a series of paradoxes had had on his earlier
commonsense and scientific outlook.8 And recall also Aristotle’s similar explanation of
Plato’s theory of forms, according to which it was originally motivated by Plato’s desire
to escape the conception of Heraclitus and Cratylus that everything is in flux, so that
scientific knowledge is impossible.9
In short, what really interests me here is Hegel’s general thesis that every genuine
philosophy has a skeptical side (in a broad sense of the word “skeptical” in which it
connotes subversive epistemology) either because the philosophy is itself skeptical or
because it is a response to skepticism – a thesis which Hegel in particular, and with
considerable generic plausibility, illustrates by means of the example of Plato.
*
This thesis seems to me interesting in the context of a very basic question that any
philosopher surely needs to ask himself at some point: What makes philosophy
philosophy? In particular, what distinguishes it from such closely related fields as, for
example, religion or natural science?
8
Phaedo, 89c ff. (In citing and quoting ancient texts in this article I have generally used
the relevant Loeb editions, sometimes, though, modifying the translations in those
editions without specific notice.) Friedrich Schlegel, whose 1800-1 lectures on
Transcendental Philosophy seem to have inspired Hegel’s thesis about the intimate role
of skepticism in philosophy, likewise focused on Plato as an example, but unlike Hegel
actually cited the Phaedo (rather than the Parmenides). Concerning this, see my
“Schlegel and Hegel on Skepticism and Philosophy” (forthcoming).
9
Metaphysics, 987a-b, 1078b.
In raising this question, I do not mean to imply that it must be possible to provide a
strict definition – a set of non-trivial, essential necessary and sufficient conditions – for
any general term, such as “philosophy,” on pain of otherwise failing properly to
understand it. The (originally Socratic, Platonic, and Aristotelian) notion that it must
always be possible to supply such a definition for a general term is a mistake, and has
long since been exposed as such (especially by the later Wittgenstein).10 Perhaps
“philosophy” is instead a “family resemblance” concept (as Morris Weitz has plausibly
argued that “art” is, and Alastair Fowler that “literature” is).11 Even after that mistake has
been set aside, it still seems reasonable to expect that we should be able to provide some
fairly informative criteria for properly calling something “philosophy” – as opposed to,
say, “religion” or “natural science.” So what might these be?
Subject matter does not look like a promising answer. Philosophers as a group discuss
virtually anything and everything. And accordingly, specific areas of the discipline
largely overlap in subject matter with other disciplines: Philosophy of religion and
religion itself (or theology) mostly treat of the same subject matter. So do philosophy of
science and natural science. And this sort of overlap occurs in many other areas of
philosophy as well – for example, moral philosophy overlaps with morality itself;
philosophy of mind with psychology; epistemology with cognitive psychology;
philosophy of mathematics with mathematics itself.
For a detailed treatment of this subject, see my “Wittgenstein on Family Resemblance
Concepts,” in Wittgenstein’s Philosophical Investigations: A Critical Guide, ed. A.
Ahmed (Cambridge: Cambridge University Press, 2010).
11
See M. Weitz, “The Role of Theory in Aesthetics,” The Journal of Aesthetics and Art
Criticism, 15/1 (1956); A. Fowler, Kinds of Literature: An Introduction to the Theory of
Genre and Modes (Cambridge, Mass.: Harvard University Press, and Oxford: Clarendon
Press, 1982).
10
Nor does approach look like a promising answer. For paradigmatic philosophers
routinely disagree in deep ways about what the approach of their discipline should be. A
sort of science of man (the Sophists, J.S. Mill)? A sort of handmaiden to natural science
(Bacon and the positivists)? A description of the most general concepts and principles,
those that apply to reality as such (Aristotle and the metaphysical tradition)? Inquiry
about inquiry (John Passmore)?12 . . .
Nor does method look like a promising answer. For here again paradigmatic
philosophers routinely disagree in deep ways about what their discipline’s method should
be. A destructive elenchus applied to ethical claims (Socrates)? A more constructive and
broader dialectic (Plato, Hegel)? A destructive balancing of opposed arguments leading
to suspension of judgment (the Pyrrhonists)? A geometrical method for expounding the
one substance (Spinoza)? A sort of empirical inquiry concerning the mind (Hume)? A
transcendental investigation into the conditions of the possibility of experience (Kant)?
Phenomenological description (Husserl)? Conceptual analysis (Russell)? Linguistic
analysis (Wittgenstein, Austin)? . . .
What I want to suggest is that Hegel’s thesis provides a much more promising answer
to our question: It is a criterion (a necessary and sufficient condition) of something’s
being philosophy – as opposed to, say, religion or natural science – that it have a
skeptical side, i.e. either itself be a form of skepticism or else be deeply concerned to
answer skepticism.
Two clarifications of this suggestion may be in order before we proceed further. First,
in making it I mean, like Hegel himself in certain moods, to employ a very broad
J. Passmore, “Philosophy,” in The Encyclopedia of Philosophy, ed. P. Edwards (New
York/London: Macmillan, 1967).
12
conception of “skepticism” that covers not only skepticism strictly so called – say,
Pyrrhonism with its distinctive skeptical methods, such as the equipollence method – but
also a considerably wider range of systematic negative intellectual assaults on received
beliefs or claims to knowledge. For example, in an ancient context this would also
include Xenophanes’ attack on divine inspiration and on the senses as sources of
knowledge; Parmenides’ attack on the coherence of the concept of not-being (and on
further concepts and beliefs which depend on it); Zeno’s paradoxes of motion; the
Sophists’ antilogic; Socrates’ elenchus; and so on. In other words, my suggestion
concerns “skepticism” in the sense of subversive epistemologies.
Second, I offer this suggestion neither as a simple discovery of the real essence of
philosophy nor as a mere stipulative definition, but rather – a third possibility that lies
somewhere between the two, though closer to the former than to the latter – as a sort of
“rational reconstruction” of what philosophy consists in. To borrow (and slightly modify)
a helpful description of such a project that John Passmore has already given: “The test of
whether a ‘rational reconstruction’ of philosophy is a reasonable one is whether it
provides us with a method of demarcating philosophy from other forms of inquiry, even
if in order to do so it is obliged to exclude much that ordinarily passes as philosophy
[Passmore might usefully have added: or to reclassify some of what ordinarily passes as
something else as philosophy. – M.N.F.]. The rational reconstructor [though] is not so
much prescribing as drawing attention to a difference.”13
*
13
Ibid., 6:224.
A clue that there may be something to this Hegelian thesis can already be found in the
earliest origins of the term “philosophy.” Diogenes Laertius (in a passage confirmed by
Clement) reports the following on that subject: “The first to use the term philosophy, and
to call himself a philosopher [lit. ‘lover of wisdom’] was Pythagoras; for, he said, no man
is wise but god alone. Heraclides of Pontus, in his De Mortua, makes him say this . . . All
too quickly the study was called wisdom and its professor a sage, to denote his attainment
of mental perfection; while the student who took it up was a philosopher.”14 According to
this credible report, then, the term “philosophy” initially connoted a certain sort of deeply
skeptical stance, only later coming to connote aspirations to overcome skepticism by
attaining knowledge.
This double use of the term to connote either a sort of skepticism or a sort of antiskepticism aimed at attaining knowledge is, I think, still visible in Plato. On the one hand
(and this is a fact that has usually been overlooked), Plato’s Socrates, especially in early
dialogues, often still seems to be using the term in something very much like the earlier
of the two senses distinguished by Diogenes (rather than in the later sense of a positive
search for knowledge). For example, in the early dialogue Euthydemus Socrates is happy
to allow that the Sophists Euthydemus and Dionysodorus are philosophers (304d-307c),
even though he clearly thinks that they care nothing at all for real wisdom or truth, only
for displaying their cleverness in verbal combat. Here the term seems to connote a certain
sort of negative activity: the activity, shared in common by these Sophists and Socrates
himself, of conducting a type of refutatory conversation (which Plato in both cases calls
14
Diogenes Laertius, Lives of Eminent Philosophers, I.12.
elenchein). This may well be Socrates’ idea when he describes himself as
“philosophizing” in the Apology as well. For example, in the phrase there “I should spend
my life philosophizing and cross-questioning myself and the others” (28e), he seems
almost to equate philosophizing with cross-questioning oneself and others (cf. 23c-d,
29c-d; also Lesser Hippias, 363a; Gorgias, 486a-d). In addition, Socrates’ use of the term
in the Apology to describe himself seems to connote his own (and other people’s) lack of
knowledge, and his awareness of this ignorance. For it is in the context of discussing
precisely this that he first applies the term to himself at 23d, and his introduction of the
term there seems intended to mark a sharp contrast between himself and the Sophists
whom he has just been discussing as people who by contrast do claim to have knowledge
(see especially 19e-20c). Moreover, Lysis, 218a and Symposium, 203e-204a both
explicitly show him using the term to connote a condition in which a person lacks
knowledge and is also aware of the fact. In addition, and echoing a further central aspect
of the earlier usage of the term reported by Diogenes, Socrates’ introduction of the term
at Apology, 23d occurs immediately after he has drawn a sharp contrast between such
human ignorance and divine knowledge (23a-b). And similarly, at Phaedrus, 278d he
says that “the epithet ‘wise’ . . . befits god alone, but the name ‘philosopher’ or
something of the sort would be more fitting and modest [for a man].” In short, Plato’s
dialogues, especially his early ones, seem to contain a usage of the term “philosophy”
that corresponds very closely to the earlier of the two usages distinguished by Diogenes:
a usage that (rather than connoting any positive search for knowledge) connotes the
skeptical stance of conducting refutatory conversations which display the refuter’s
recognition of human ignorance (including his own), in contradistinction to divine
knowledge.
On the other hand, and much more famously, Plato’s dialogues, especially his middle
and late ones, also contain a usage of the term “philosophy” that answers very closely to
Diogenes’s second, later sense: that of a positive search for knowledge in the face of
skeptical difficulties. (See, for example, Lysis, 218a; Phaedo, 61d ff.; Republic, 485a ff.;
Symposium, 203e–204a; Theaetetus, 173c–174b.)
*
How well does the Hegelian thesis fare when considered in the light of what philosophers
actually do, though?
Given that, as I am conceiving it, it involves rational reconstruction, its success does
not require that every so-called philosopher or philosophy should conform to the
proposed criterion of being either skeptical or anti-skeptical. However, it is important that
paradigmatic philosophers and philosophy should do so. So how does the thesis fare in
this light?
It seems to me that our existing ways of classifying thinkers as “philosophers” or “nonphilosophers,” and their ideas as “philosophy” or “non-philosophy,” within an ancient
context conform pretty well to this thesis. For example, we usually classify as
“philosophy” both the broadly skeptical positions of Xenophanes, the Eleatics, the
Sophists, Socrates, the Pyrrhonian skeptics, and the Academic skeptics and the broadly
anti-skeptical positions of Plato and the Stoics. But we do not normally classify as
“philosophy” the neither skeptical nor anti-skeptical religion of Homer or the neither
skeptical nor anti-skeptical natural science of Hippocrates.15
There is a problem case, however: Aristotle. Aristotle is certainly a paradigmatic
philosopher, if ever there was one. Yet he can easily seem, and indeed has seemed to
many, to be quite unconcerned with skepticism. As one recent author has put it,
“Aristotle, throughout all his writings, is . . . notorious in balking at skeptical questions.
He just does not take the skeptic seriously at all.”16 If Aristotle really were as free of
concerns about skepticism as this implies, then that fact would constitute a pretty
powerful argument against the Hegelian thesis that skepticism plays an essential role in
philosophy. I would therefore like to devote much of the remainder of this article to
taking a closer look at the case of Aristotle. My goal here will not, of course, be to
15
The Hippocratic writings, especially On Ancient Medicine, show some interest in, and
indeed sympathy with, what might in an extremely loose sense be called skeptical ideas
(see on this H.J. Hankinson, The Skeptics [London/New York: Routledge, 1995], 34).
However, even in the work just mentioned, the “skepticism” in question is not targeted
against traditional beliefs but only against philosophical-medical rationalism, and
moreover the response to it is meant to be continuous with traditional beliefs and
procedures.
16
M. Aydede, “Aristotle on epistêmê and nous: the Posterior Analytics,” Southern
Journal of Philosophy, 36/1 (1998); here quoted from the longer version of the article at
http://www.philosophy.ubc.ca/faculty/aydede/Aristotle.pdf where the quoted passage
appears at 22, n. 43. The most sophisticated and influential recent representative of this
sort of reading of Aristotle is M.F. Burnyeat, “Aristotle on Understanding Knowledge,”
in Aristotle on Science: The “Posterior Analytics,” ed. E. Berti (Padua: Editrice
Antenore, 1981), esp. 132-8. Cf. S. Everson, in Companions to Ancient Thought I:
Epistemology, ed. S. Everson (Cambridge: Cambridge University Press, 1990), pp. 5-8.
Also C.C.W. Taylor, “Aristotle’s Epistemology,” ibid., 116: “While Aristotle was
certainly aware of skeptical challenges to claims to knowledge, . . . the justification of
knowledge claims in response to such challenges . . . is at best peripheral to Aristotle’s
concerns.” Also J. Barnes, “An Aristotelian Way with Scepticism,” in Aristotle Today:
Essays on Aristotle’s Ideal of Science, ed. M. Matthen (Edmonton, Alberta: Academic
Printing and Publishing, 1987), 53: “It is often said that problems of epistemology only
come centre-stage in the Hellenistic period. It is sometimes inferred that such problems
were foreign to Aristotle – that it is inappropriate, or anachronistic, or perhaps merely
pointless, to guess what his views on the criterion might have been.”
support the Hegelian thesis by doing induction from a single example! Rather, it will be
to defend it by defusing what is perhaps the most threatening-looking candidate
counterexample to it.17
*
A good place for that defusing to begin may be with Aristotle’s famous account in the
Metaphysics of what, in his view, originally motivated, and continues to motivate,
philosophers: “It is through wonder that men now begin and originally began to
philosophize; wondering in the first place at obvious perplexities [ta procheira tôn
aporôn].”18 Compare with this Aristotle’s more specific account (already mentioned
above) that Plato’s theory of forms had its origins in his perplexity at the doctrine of
Heraclitus and Cratylus that everything is in flux, and that scientific knowledge is
therefore impossible –19 a conception of the motive for philosophy with which Aristotle
himself expresses sympathy at one point.20
17
A natural addition to, or extension of, this candidate counterexample would be the
Aristotelian tradition in medieval and early modern philosophy. I shall therefore also
attempt in this article – albeit in a far more sketchy way, and mainly in the notes – to
defuse that tradition as a counterexample.
18
Metaphysics, 982b; cf. 995a-b.
19
Ibid., 987a-b, 1078b.
20
Ibid., 1010a. Especially since this article will to some extent be concerned with debts
that Pyrrhonism owes to Aristotle, it is perhaps worth pointing out here that this whole
Aristotelian account of the origins of philosophy, together with a striking passage from
the Physics in which Aristotle equates knowledge or understanding with the cessation of
the soul’s turbulence [tarachê] and the attainment of stillness (247b: “the condition of
understanding or knowing results from the soul coming to a state of stillness out of the
turbulence natural to it [ek tês physikês tarachês]”), seems to have furnished the first half
of Sextus Empiricus’s famous account at Outlines of Pyrrhonism, I.25-9 of how one
becomes a skeptic. (The other half of Sextus’s account is that the philosophers’ attempts
In accordance with this general position, it is surely at least clear on reflection that
much of Aristotle’s philosophy is concerned to answer skepticism in the broad sense that
I distinguished earlier: skepticism qua systematic negative intellectual assaults on
received beliefs or claims to knowledge (i.e. subversive epistemology).
Let me briefly indicate a few of the ways in which this is so. First, much of
Metaphysics, book Gamma is devoted to refuting forms of skepticism about the law of
contradiction (including Heraclitus’s form of it), and about the law of excluded middle.
Second, book Gamma in addition continues a project already begun by Plato’s Theaetetus
of refuting the subversive epistemology of Protagoras, namely his relativism; for
example, it replays Plato’s self-refutation charge against Protagoras’s relativism.21 Third,
book Gamma also attempts to refute a broader range of skeptical ideas – including, for
example, Xeniades’ (and perhaps also Gorgias’s) thesis that every claim is false.22
Fourth, in the Physics and elsewhere Aristotle attempts to refute Parmenides’ case for the
incoherence of the concept of not-being – indeed, achieving this goal seems to be one of
Aristotle’s main motives for introducing his fundamental concept of matter (in
contradistinction to form).23 Fifth, Aristotle devotes much of the Physics to refuting
Zeno’s paradoxes of motion – by, inter alia, sharply distinguishing between infinite
divisibility and infinite extension; insisting that space’s infinite divisibility is matched by
to resolve the initial conflicts and hence overcome mental turbulence – in the way
envisaged by Aristotle – fails, since conflicts reappear at the level of the philosophical
theories themselves, but that the skeptic has found – to his initial surprise – that by giving
up such theories in response to that problem and simply suspending judgment, lo and
behold mental turbulence disappears.)
21
Metaphysics, 1012b.
22
Ibid., 1012a-b.
23
See esp. Physics, 186a-187a, 191b-192a. Cf. On Sophistical Refutations, 167a, 180a;
De Interpretatione, 21a.
that of time; and claiming that spatial and temporal points exist only potentially, not
actually.24 Sixth, On Sophistical Refutations is largely devoted to the task of identifying
and defusing a whole range of fallacies on which the Sophists and others had relied in
making various sorts of skeptical arguments. Seventh, in the Metaphysics Aristotle
implies that the reason why Socrates failed to achieve the positive goal of arriving at
satisfactory definitions in ethics, instead getting bogged down in elenctic refutations and
achieving no answer of his own, was that he lacked Aristotle’s own technique of
dialectic.25 So Aristotle apparently conceives the sort of dialectical inquiry into ethical
questions that he himself undertakes in the Nicomachean Ethics to be (among other
things) a way of defusing Socratic elenchus.
In short, a concern to rebut various types of skepticism in the broad sense is a
pervasive feature of Aristotle’s philosophy.
*
In addition, though, and perhaps more surprisingly, it also seems plausible to see
Aristotle as anticipating and addressing the sorts of challenges to belief and knowledge
that would later typify skepticism in the narrow sense, Pyrrhonism.26
24
Physics, bk. 6 and 263a-b.
Metaphysics, 1078b. Cf. On Sophistical Refutations, 183b.
26
Consequently, when the French Aristotelians in the early seventeenth century set out to
combat Pyrrhonism by invoking Aristotle’s philosophy (see R.H. Popkin, The History of
Skepticism from Erasmus to Spinoza [Berkeley and Los Angeles: University of California
Press, 1979], 118-28), they were, in my view, largely retreading a path that Aristotle had
himself already trodden.
25
My case for saying this will fall into two parts. The first part is heavily indebted to
some recent secondary literature on the subject, including Jonathan Barnes’s essay “An
Aristotelian Way with Scepticism” and especially Anthony Long’s essay “Aristotle and
the History of Greek Skepticism.”27 The second part is significantly indebted to Hegel.
Here is the first part of my case. Perhaps the most striking example of Aristotle
anticipating and responding to Pyrrhonism’s challenges concerns the Pyrrhonian tropes of
Agrippa, or more precisely the central subset of them that has recently been dubbed the
“Agrippan trilemma”:28 infinite regress, vicious circularity, or dogmatic presupposition
(and consequent vulnerability to a contrary dogmatic presupposition).29 At Posterior
Analytics, 72b-73a Aristotle in effect (if not entirely in intention) does the following three
things: (1) he draws attention to a cruder proto-form of the trilemma’s problem that had
already been advanced by certain predecessors; (2) he refines it into the fuller and subtler
form that we later find in the Pyrrhonists; and (3) he proposes a response to it.30 The
cruder proto-form of the problem that Aristotle finds before him – a proto-form probably
due to Antisthenes – says that knowledge is impossible because undemonstrated
presuppositions cannot constitute knowledge and the attempt to avoid them leads to
infinite regress.31 Aristotle’s refinement of that problem comes in his rejection of a
proposal some other people had apparently already made that the solution to it lay in
A.A. Long, “Aristotle and the History of Greek Skepticism,” in Studies in Aristotle, ed.
D.J. O’Meara (Washington, D.C.: Catholic University of America Press, 1981).
28
I borrow this useful expression from Michael Williams and Paul Franks.
29
For discussion of this topic, cf. Long, “Aristotle and the History of Greek Skepticism,”
86-8; also, Aristotle, Posterior Analytics, ed. J. Barnes (Oxford: Clarendon Press, 1994),
editor’s commentary at 103-4.
30
To be a bit more exact, he does (1) both in effect and in intention; but (2) and (3) in
effect though not quite in intention.
31
Posterior Analytics, 72b.
27
circular demonstration. Aristotle argues that such circularity would be vicious – in
particular, because genuine demonstration requires that the premises be better known
than the conclusion, and such an epistemic asymmetry obviously cannot hold in two
directions at once.32 This rejection of circular demonstration in effect leaves the reader
with the full Agrippan trilemma (indeed, it seems almost certain to me that Agrippa got it
from just this source). However, Aristotle also proposes a solution to the problem. His
solution is that it is a mistake to assume that undemonstrated presuppositions cannot
constitute knowledge: “We, however, hold that not all knowledge is demonstrative: the
knowledge of immediate premises is not by demonstration . . . Indeed we hold not only
that scientific knowledge is possible, but that there is a definite first principle of
knowledge by which we recognize ultimate truths/definitions [tous horous]” (Aristotle
here means the faculty of nous).33 Aristotle invokes this position that it is sometimes
perfectly proper to accept presuppositions without a demonstration, and that it is a
mistake always to expect a demonstration, in many other places as well (e.g.
Metaphysics, 1006a, 1011a).
Another striking example of Aristotle already anticipating and responding to
Pyrrhonism’s challenges concerns the Pyrrhonian tropes of Aenesidemus, in particular
those among them that deal with sensory perception. As Long points out, several of these
tropes – especially, the ones concerned with discrepancies in sensory perception between
human beings and animals, between different human beings, and within a single human
32
Ibid., 72b; cf. 72a.
Ibid., 72b. Aristotle goes on at 81b-84b to try to provide a more ambitious technical
case that demonstration must eventually come to an end with undemonstrated first
principles. But the case is obscure, and – as G. Grote argues in Aristotle (repr. New York:
Arno Press, 1973), 228-30 – may well not work.
33
being – are already anticipated by Aristotle in Metaphysics, book Gamma –34 where
Aristotle seems to associate them mainly with Democritus, who, he says, inferred from
them “that either there is no truth or we cannot discover it.”35 Moreover, Aristotle
develops a battery of responses to such skeptical problems. Perhaps the most important of
these is a doctrine he espouses prominently in De Anima to the effect that perception is
always true when it only concerns its own proper objects, e.g. in the case of vision color,
or in the case of hearing sound: “Each sense has its proper sphere, nor is it deceived as to
the fact of color or sound, but only as to the nature and position of the colored object or
the thing which makes the sound.”36 At Metaphysics, 1010b Aristotle explicitly deploys
this doctrine against the sorts of skeptical problems in question. Aristotle also makes, or
at least strongly hints at, a range of further responses. For example, at Metaphysics,
1010b he develops an early version of the argument – later famously exploited against the
Pyrrhonists both by their ancient opponents and by Hume – that such a skeptic’s actions
contradict his professed skepticism.37 And as Barnes and Long both point out, Aristotle
also strongly hints at an argument to the effect that the biological function of the senses
requires that they be at least generally veridical. Such, in short, are Aristotle’s
anticipatory answers to Pyrrhonian doubts concerning sensory perception.38
Metaphysics, 1009b. Cf. Long, “Aristotle and the History of Greek Skepticism,” 89-91.
Metaphysics, 1009b.
36
De Anima, 418a. Aristotle, more circumspectly, qualifies the doctrine slightly at 428b:
“Perception of the proper objects is true, or contains the least possible falsity.”
37
Cf. Long, “Aristotle and the History of Greek Skepticism,” 94-7.
38
In connection with medieval Aristotelianism, note that Aquinas essentially continues
this Aristotelian anti-skeptical position. In particular, Aquinas accepts Aristotle’s doctrine
that perception is (virtually) always true when concerned with its own proper objects (see
The Summa Theologica, in The Basic Writings of Saint Thomas Aquinas, ed. A.C. Pegis
[Indianapolis: Hackett, 1997], 182-3, 825). And Aquinas also implies that the (biological)
function of the senses requires their general veridicality.
34
35
At least in these two ways, then, Aristotle already anticipates and attempts to solve
Pyrrhonian skepticism’s characteristic problems.39
*
But it seems to me that Aristotle’s anticipation of, and response to, skepticism in the
narrow sense, i.e. Pyrrhonism, actually goes much further than this. So I would like now
to turn to the second part of my case, the part that is indebted to Hegel.
If Aristotle’s anticipation and response only went as far as has just been explained, it
might perhaps still be reasonable to say, with Myles Burnyeat in his influential essay
“Aristotle on Understanding Knowledge,” that unlike the skeptics and the positive
philosophers of the Hellenistic period, who would make epistemological challenges their
starting-point, Aristotle, while he is familiar with skeptical arguments that threaten his
enterprise and thinks some of them worthy of extended discussion, “is simply very firm
that he is not going to let them structure his inquiries or dictate his choice of startingpoints.”40 In other words, Aristotle’s engagement with skepticism in the narrow sense
would remain relatively superficial. However, I strongly suspect that the truth about
Aristotle is actually quite otherwise.
39
It should perhaps be mentioned here that F. Grayeff, Aristotle and His School (London:
Duckworth, 1974) has made an entirely different sort of case for the role of skepticism in
Aristotle’s works – a case to the effect that certain parts of the Metaphysics, including for
example book little Alpha, were not written by Aristotle at all but instead by later
peripatetics who reflect in them an actual knowledge of the historical skeptics and their
ideas, as well as a concern to respond to these. However, I share Long’s skepticism about
this whole line of interpretation (“Aristotle and the History of Greek Skepticism,” 106).
40
Burnyeat, “Aristotle on Understanding Knowledge,” 138.
Hegel can help us here, at least indirectly. To my knowledge, he nowhere explicitly
attempts to show that his thesis that every genuine philosophy has a skeptical side holds
true of Aristotle (he at least fails to do so in the two most likely places, his 1802 essay
and his later lectures on the history of philosophy). Nonetheless, he does make several
important observations which can contribute towards achieving such a goal – towards
showing that Aristotle’s philosophy is deeply concerned with forestalling skepticism in
the narrow sense, Pyrrhonism.
First, and most generally, in the lectures on the history of philosophy Hegel
emphasizes that both Plato and Aristotle were preceded by, and worked in reaction to, the
Sophists, especially Protagoras and Gorgias. This is quite correct. It is obvious enough
where Plato is concerned. But it is also true of Aristotle – as can be seen, for example,
from his numerous discussions of Protagoras and Gorgias in the Rhetoric, and from his
attempts to refute Protagoras in Metaphysics, book Gamma.
Second, and more specifically, both in his lectures on the history of philosophy and in
his lectures on the philosophy of history Hegel emphasizes that the Sophists had already
brought two epistemological problems to the fore. The first of these was the problem of
an equal balance of opposing arguments (a problem that was developed above all by
Protagoras in his lost works on antilogic, but which is also represented by several
surviving Sophistic works of lesser stature, in particular Antiphon’s Tetralogies and the
Dissoi Logoi). The second was what I have elsewhere called the problem of conceptinstantiation, i.e. the problem that our concepts may lack any instances in reality at all
(this problem receives a global application in Gorgias’s treatise Concerning the Nonexistent or Concerning Nature and a more local application in Protagoras’s famous
agnosticism about whether or not gods exist).41 Now these two problems would later
come to constitute the very core of Pyrrhonian skepticism: the former problem is
essentially identical with Pyrrhonism’s problem of “equipollence,”42 while the latter
problem reappears in the form of Pyrrhonism’s pervasive concern with the possibility that
even our fundamental concepts – e.g. god, place, and time – may be empty.43
Third, while, as I mentioned before, Hegel nowhere explicitly applies his thesis that
every genuine philosophy has a skeptical side to Aristotle, some of his remarks in the
1802 essay do so implicitly. Hegel’s interest in Aristotle is often thought to have begun
only much later, and there is indeed no explicit discussion of Aristotle in the 1802 essay.
However, some comments that Hegel makes in a roughly contemporary work, Logica et
Metaphysica from 1801/2, show that Aristotle was in fact already very much on his mind
as a paradigmatic philosopher at this period.44 Now, in the 1802 essay itself Hegel argues
that the Pyrrhonists’ equipollence problem can have no effect against the principle of his
41
Cf. my Hegel and Skepticism, 65 ff.
It is true that the Sophists’ application of this problem did not usually lead to the same
result that it would later lead to with the Pyrrhonists, namely suspension of judgment (for
example, Protagoras’s usual response to it was instead relativism). However, that is really
a further issue. Moreover, it evidently sometimes did – as can be seen, for example, from
Plato’s description of the misologist in the Phaedo, and from the fact that in the particular
case of the question of the existence and nature of the gods the application of this
problem apparently led Protagoras to his agnosticism (instead of to his more usual
response of relativism).
43
In seeing Pyrrhonism as continuous with Sophism, and especially with Protagoras, I
am in broad agreement with P. Natorp, Forschungen zur Geschichte des
Erkenntnisproblems im Altertum (Berlin: Wilhelm Hertz, 1884). By contrast, the noted
French scholar of ancient skepticism Brochard seems to me profoundly mistaken when he
holds that Pyrrhonism owed nothing of importance to Sophism (V. Brochard, Les
Sceptiques grecs [Paris: J. Vrin, 1923], 45-7).
44
Logica et Metaphysica in G.W.F. Hegel, Gesammelte Werke (Hamburg: Felix Meiner,
1998), vol. 5; also translated in my Hegel’s Idea of a “Phenomenology of Spirit”
(Chicago: University of Chicago Press, 1998), 586-90. In this early text Hegel adduces
Aristotle and his relationship to Alexander the Great as the most important historical
example of philosophy playing an active role in changing the world.
42
own philosophy because that principle has no opposite: “the Rational has no opposite.”45
And he also implies that the Pyrrhonists’ concept-instantiation problem can have no
effect against his own philosophy’s principle because “Reason is cognizant of itself
through itself,”46 so that here “thinking and being are one.”47 These two doctrines must, I
think, be interpreted as conscious echoes of two strikingly similar doctrines concerning
the nature of divine intelligence from (what would at least later be) Hegel’s favorite book
of Aristotle’s Metaphysics, book Lambda. Specifically, the former doctrine (that the
principle of philosophy has no opposite) seems to echo Aristotle’s statement there: “On
all other views it follows necessarily that there must be something which is contrary to
wisdom or supreme knowledge, but on ours it does not. For there is no contrary to that
which is primary, since all contraries involve matter, and that which has matter exists
potentially; and the ignorance which is contrary to wisdom would tend towards the
contrary of the object of wisdom; but that which is primary has no contrary.”48 And
Hegel’s latter doctrine (that Reason only knows itself, so that in this case thinking and
being are one) seems to echo Aristotle’s famous statement in book Lambda that “rational
thought thinks itself through participation in its object; for it becomes an object of
thought by the act of apprehension and thinking, so that thought and the object of thought
are the same.”49
45
Werke, 2:247.
Ibid., 235.
47
Ibid., 251.
48
Metaphysics, 1075b.
49
Ibid., 1072b. Cf. 1074b: “Therefore rational thought thinks itself, if it is that which is
best; and its thinking is a thinking of thinking.” Also 1075a: “Therefore since rational
thought and its object are not different in the case of things which contain no matter, they
will be the same, and the act of rational thinking will be one with its object.”
46
Indeed, at least in the latter case the fact that Hegel is alluding to Aristotle can be
established with virtual certainty, in light of the following three considerations: (1)
Hegel’s defense of the doctrine in question in his 1802 essay is explicitly aimed against
an attack on it that had been launched by Sextus Empiricus at Against the Logicians,
I.310. Now Sextus himself only ascribes the doctrine vaguely to “the dogmatic
philosophers.” But it seems clear that he largely has Aristotle and his followers in mind.
Moreover, while Hegel does not mention that it belongs to Aristotle in the 1802 essay
itself, he does so later in his lectures on the history of philosophy.50 (2) Hegel would also
later explicitly quote Aristotle’s just-cited statement of the doctrine as the very climax of
his own Encyclopedia.51 Finally, (3) Hegel would also later discuss that statement and its
doctrine sympathetically in his chapter on Aristotle in the lectures on the history of
philosophy.52
In short, Hegel already in the 1802 essay implies that Aristotle anticipated the skeptical
equipollence and concept-instantiation problems and constructed these two responses to
them.
Is Hegel right about this? It is difficult to be sure. But I think that he may well be. In
particular, the most likely sources of reservations concerning his interpretation turn out to
be ill founded. One such source would be a doubt that Aristotle was concerned about
50
G.W.F. Hegel, Vorlesungen über die Geschichte der Philosophie II, in Werke, 19:399:
“Sextus Empiricus [Footnote: Adversus Mathematikos, VII, secs. 310-312] . . . reaches
the speculative Idea concerning the intellect, that it cognizes itself, as the self-thinking of
thought, that thought is the thought of thought, absolute thought, ‘or that Reason
comprehends itself’ and in its freedom is by itself. We saw this with Aristotle. In order to
refute this Idea, Sextus argues in the following way . . .” (emphasis added).
51
G.W.F. Hegel, Enzyklopädie der philosophischen Wissenschaften im Grundrisse III
(1830), in Werke, 10:395.
52
Werke, 19:162-7.
equipollence and concept-instantiation problems in the first place. However, as we are
going to see in more detail shortly, he was – for example, at Topics, 145b he mentions a
traditional conception of aporia as “equality of contrary reasonings”; and at Posterior
Analytics, 89b he identifies the question of whether or not a concept has any instances as
one of the four types of question that interest inquirers. Another likely source of
reservations about Hegel’s interpretation would be the thought that in Metaphysics, book
Lambda Aristotle is concerned with divine cognition rather than human cognition,
whereas the skeptical problems in question are challenges to human cognition. But this
worry is answerable as well. For one thing, if Aristotle is concerned with the problems in
question at all (as he evidently is), then it would surely be quite natural of him to want to
solve them on behalf of divine knowledge. For another thing, as Hegel himself
emphasizes in the course discussing Aristotle’s Metaphysics in the lectures on the history
of philosophy,53 Aristotle believes that human philosophers can at least temporarily share
in this divine knowledge.54 So, actually, a defense of this divine knowledge against the
problems in question would also be a defense of a certain sort of human knowledge
against them.
However, I shall not pursue this particular interpretive question concerning Aristotle
any further in what follows. For, whether or not Hegel turns out to be right about it in the
end, I think that his more generic implication here that Aristotle has anticipated the
equipollence and concept-instantiation problems and has sought to forestall them at a
very fundamental level of his theory remains a profoundly insightful one. And it is this
more generic implication that I would like to pursue further in what follows. For I believe
53
54
Ibid., 162-3.
See Metaphysics, 1072b. Cf. Nicomachean Ethics, 1177a-b, 1178b.
that it is (also) borne out in some different areas of Aristotle’s philosophy, and that this
fact turns out to be of at least as great interpretive importance as, and perhaps even
greater philosophical importance than, its (arguable) application in the area of Aristotle’s
views concerning divine knowledge.
*
Let me begin, then, with the equipollence problem. One of the things that Aristotle has in
mind when he characterizes philosophy’s origins and continued motivation as lying in
perplexity, or aporia – and accordingly, makes the dissolution of aporiai a central part of
his own philosophical method – is an equal balance of opposing arguments. For in the
Topics he refers to a traditional conception of aporia as “equality of contrary reasonings
[isotês enantiôn logismôn]” (145b).55 And many of his own presentations of aporiai – for
example, in Metaphysics, book Beta; at several points in the Posterior Analytics; and at
Physics, 213a-b (the discussion of whether or not void exists) – are articulated in
something very much like that form. Accordingly, Cicero reports that “Aristotle set on
foot the practice of arguing pro and contra upon every topic, . . . setting out all the
possible arguments on either side of every subject.”56
How does Aristotle intend to cope with this skeptical threat? One important part of his
answer to it lies in his famous method of dialectic, i.e. his method of striving to reconcile
apparently conflicting positions on issues (especially when those positions carry weight
Cf. Long, “Aristotle and the History of Greek Skepticism,” 83-4.
Cicero, De Finibus, v, 10. (It should be kept in mind here that Cicero may have had
additional textual evidence available which we lack.)
55
56
because they are held my most people or by experts on the subject in question). The
Sophists’ generation of equipollence problems had largely focused on ethical issues, and
accordingly Aristotle’s deployment of this response is especially salient in the area of
ethics. For example, in the Nicomachean Ethics he opens with a consideration of a range
of apparently conflicting views about what happiness consists in (external goods,
pleasure, etc.), and then attempts to reconcile them in a certain way within a single
theory. Similarly, the work’s subsequent discussion of akrasia starts out from the sort of
seemingly sharp opposition between different views on the subject that Plato had already
characterized in the Protagoras – the many’s view that knowledge of the good can be
overcome by pleasure vs. Socrates’ (and perhaps also Protagoras’s) view that it cannot –
and then attempts to reconcile these in a certain manner.57 In this way, the threat of
equipollence is defused.
But Aristotle’s answer to the skeptical threat of equipollence also goes beyond that. In
particular, his position in the Posterior Analytics that some principles can be known to be
true without any supporting demonstration, and that it is a mistake to expect a
demonstration in their support, constitutes another important part of his answer to this
skeptical threat (as well as to such distinct but related skeptical threats as the rejection of
any claim made without a supporting demonstration, simply treating the question
addressed by such a principle as an open one, or denying such a principle outright).
57
In effect, Aristotle concedes to the many that a person can know the general
proposition about the good that constitutes the major premise of a practical syllogism and
also the perceptually based minor premise and yet still fail to act accordingly on a
particular occasion because influenced by pleasure, but Aristotle also concedes to
Socrates (and Protagoras) that this must be through a sort of ignorance of the good,
specifically an ignorance of the syllogism’s conclusion about the goodness of the
particular course of action in question, as evidenced (or constituted) by the agent’s failure
to act.
Actually, Aristotle holds versions of such a position in two distinct areas. One area
where he thinks that propositions can be known to be true without any supporting
demonstration is that of perceptual judgments concerning a sense’s own proper objects.
However, the Posterior Analytics has another area in mind: the first principles of the
sciences. And it is in this area that Aristotle’s position is less easily understood and more
interesting. It is therefore his ideas concerning this second class of cases that I want to
examine in more detail here.
Concerning this second class of cases his anti-skeptical stance has a whole further
layer of sophistication that I have not yet described, and which to my knowledge has not
been properly recognized by the secondary literature. Roughly speaking, his fuller case
against any skepticism that invokes an alleged equal balance of opposed arguments in
order to destroy the credibility of first principles (or that seeks to undermine them in one
of the other ways recently mentioned: by rejecting claims that lack a supporting
demonstration, simply treating the question addressed by such a principle as open, or
denying such a principle outright) is that belief in these principles is a necessary
condition of really meaning or thinking anything at all. The skeptic must therefore
renounce his skepticism in these cases on pain of otherwise being reduced to mere
babbling.
Aristotle’s clearest, and most fundamental, deployment of this strategy is his famous
defense of the law of contradiction against skeptical doubts (or denials) concerning it in
Metaphysics, book Gamma.58 So let us begin by considering that.
58
Cf. Metaphysics, bk. Kappa, 1061b-1062a for a short re-statement of the defense.
According to Aristotle, although the law of contradiction cannot be furnished with a
demonstration, since it is the most certain of all principles, it can be provided with a sort
of negative defense against would-be opponents.59 More specifically, he claims that this
is a principle that a person must believe in order to mean or think anything at all, since it
is a principle that “one necessarily understands who understands anything” and which is
“necessarily part of the equipment of one who apprehends any of the things that are”
(1005b). And he offers an argument in support of this claim. His argument is essentially
that (1) it is impossible to believe a contradiction true, and moreover (2) in order to mean
or understand anything by words, and hence in order to be capable of thought, one must
believe the law of contradiction.60
To be more precise, Aristotle’s approach is to argue at length for (1), and then to infer
(2) more or less directly from his case for (1). The latter step might seem very
problematic at first sight, but is perhaps really not. One apparent problem with it concerns
its shift to speaking of conditions of meaning or understanding. But this apparent
problem turns out to be defused by some of the specific details of Aristotle’s case for (1)
(see below). Another apparent problem with it concerns what might seem to be a crass
non sequitur in inferring from people’s inability to believe particular contradictions to
their having to believe the law of contradiction.61 However, that inference may be
reasonable if, as seems likely, what Aristotle has in mind in (2) is implicit belief in the
law of contradiction. For a person’s consistent inability to believe any contradictions, as
affirmed by (1), might indeed reasonably be held to show that he has, or perhaps even
59
Metaphysics, 1006a.
Ibid., 1005b-1007a.
61
For such an objection, see J. Barnes, “The Law of Contradiction,” Philosophical
Quarterly, 19/77 (1969), 308-9.
60
must have, an implicit belief in the law of contradiction. Also, it should be noted that
even by itself (1) would constitute a pretty strong case for claiming that the law of
contradiction is in a sense internal to thought. In short, the success of Aristotle’s overall
argument really turns on the success of his case for (1).
Aristotle has two main arguments for (1). First, he argues that beliefs in contradictory
sentences are themselves contrary properties of a person and therefore cannot both belong
to a person at the same time.62 However, this argument really just begs the original
question, which is in effect precisely whether or not such beliefs are contrary properties
of a person.63
But second, and more interestingly, Aristotle also argues as follows: In order to mean
or understand anything by his words, and hence in order to think (or as Aristotle also
colorfully puts it, in order to avoid being “like a vegetable”), a person must signify a
subject, i.e. a (type of) substance. This requires that he signify some one thing, i.e. the
essence of a (type of) substance – for example, in the case of the subject “man,” “twofooted animal.” But to the extent that he also signified the negation of the thing in
question – for example, in this case, “not a two-footed animal” – he would fail to signify
one thing.64
This argument is likely to seem very problematic at first sight as well. But it should not
be dismissed too hastily. One immediately tempting line of objection to it is of course
62
Metaphysics, 1005b.
Barnes embraces this line of argument, and elaborates on it at some length. But he too
begs the original question, namely by assuming that belief and disbelief are contraries, so
that it is necessarily true that, as he puts it, (x) ((xD:(P))  (-xB:(P))), i.e. if anyone
disbelieves (“D”) a proposition P then he does not believe (“B”) proposition P (“The Law
of Contradiction,” 304).
64
Metaphysics, 1006a-1007a.
63
that it implicitly assumes a very questionable philosophy of language and metaphysics,
including theses to the effect that all meaning or understanding, and hence all thought,
must ultimately refer to subjects, or substances; that all substances have essences; that in
order to refer to subjects, or substances, one must signify their essences; and so on. But
this sort of objection could probably be defused by means of a little reconstruction. In
particular, the argument could be recast more simply and plausibly in terms of the rather
attractive thesis that meaning or understanding any word requires having certain
unequivocal analytic beliefs connected with it (e.g. understanding the word “bachelor”
requires having an unequivocal belief that all bachelors are unmarried), so that to the
extent that one undermined one’s claim to possess such unequivocal beliefs by also
inclining to believe opposites (e.g. that it is not the case that all bachelors are unmarried)
one would ipso facto also undermine one’s claim to mean or understand words.
This, then, is the paradigmatic example of Aristotle’s anti-skeptical strategy. Whether
it really works in the end remains a further question, which I shall not pursue here.65 But I
hope that the above account has at least shown that it is sophisticated and plausible
enough to deserve to be taken seriously.
However (and here we come to a point that has, I think, been almost entirely
overlooked by the secondary literature), Aristotle’s application of this sort of strategy
against the skeptic is also much broader; his application of it to the law of contradiction is
only a paradigm of a far wider range of applications that he gives it. He conceives the law
of contradiction as a first principle of the science that he calls “first philosophy” and
65
I have argued elsewhere that it does not. See my Wittgenstein on the Arbitrariness of
Grammar (Princeton: Princeton University Press, 2004), ch. 5 and Kant and Skepticism,
ch.12.
which we call “metaphysics,” a science whose subject matter is completely general,
“being qua being” (Metaphysics, 1003a, 1005a-b). Accordingly, he also conceives the
law as a “common principle” that is presupposed by all the sciences (Posterior Analytics,
77a). His anti-skeptical idea in this case is that in order to speak meaningfully, or to
think, about anything at all a person must believe this principle which governs being as
such. Now what needs to be noticed is that, quite analogously, but in addition, he also
holds that belief in the first principles of the more specific sciences stands in a similar
internal relation to the understanding of their more specific concepts.66 In other words,
just as in order to speak meaningfully, or to think, about anything at all one must believe
the law of contradiction, so likewise, in order to express, or to think, the concepts
pertaining to some specific science one must (in addition) believe the first principles of
that science.
In support of this interpretation, I would adduce the following five pieces of textual
evidence: First, and foremost, Aristotle generally depicts the first principles of the
sciences as not only true, explanatory propositions but also definitions, i.e. statements of
the meanings of the terms involved: “The starting-points of demonstrations are
definitions [horismoi]” (Posterior Analytics, 90b).67 Second, and accordingly, Aristotle’s
Cf. Taylor, “Aristotle’s Epistemology,” 127 for the key point here that in Aristotle’s
view a grasp of the truths expressed by the first principles of the sciences is internal to a
grasp of the very concepts involved.
67
Aristotle’s conception of definitions has Socratic-Platonic roots. Now it has often been
denied by the secondary literature that the Socratic-Platonic conception of a definition
makes it a statement of meaning. However, that is a mistake – as I have argued in detail
in “Socrates’ Demand for Definitions,” Oxford Studies in Ancient Philosophy, 31 (2006).
As I show in that article, the conception of definitions as statements of meaning is
clearest in the early Plato, but even when the middle Plato turns definitions into more
substantive explanatory principles, he does not drop that conception. I would suggest that
in this respect Aristotle’s position is perfectly continuous with the middle Plato’s.
66
famous account at the end of the Posterior Analytics according to which the first
principles of the sciences are “universals” arrived at via induction on sensory particulars
systematically fuses a conception of them as substantive general principles and as
concepts (99b-100b).68 Third, and again accordingly, in that account Aristotle
characterizes the first principles, or definitions, in question as apprehended by the faculty
of nous (100b; cf. Nicomachean Ethics, 1142a) – a faculty which Plato in the Meno and
the Republic had already intimately associated with grasping definitions, and with
possessing conceptual understanding.69 Fourth, and again accordingly, Aristotle in the
Posterior Analytics and the Metaphysics implies that, unlike lower-level true
propositions, the definitions that constitute the first principles of the sciences are not only
true but are also such that one cannot deny, be mistaken about, or doubt them, since to
attempt or to be inclined to do so would ipso facto be to deprive oneself of the very
concepts involved, to lapse into mere meaningless, thoughtless noise: “That which is in
itself necessarily true and must be thought to be so is not a hypothesis nor a postulate; for
Pace J.H. Lesher, “The Meaning of NOUS in the Posterior Analytics,” Phronesis, 18
(1973), 60-2, who (like some of the other authors of secondary literature he cites, e.g.
Tredennick) treats these as mutually exclusive possibilities. For a more helpful
interpretation, see C.H. Kahn, “The Role of NOUS in the Cognition of First Principles in
Posterior Analytics, II 19,” in Aristotle on Science: The “Posterior Analytics.”
69
For a discussion of this position in the Meno, see my “Socrates’ Profession of
Ignorance,” Oxford Studies in Ancient Philosophy, 32 (2007), 17-18. Concerning its
recurrence in the Republic, consider for example the following passage at 534b: “And do
you not also give the name dialectician to the man who is able to exact an account of the
essence of each thing? And will you not say that the one who is unable to do this, insofar
as he is incapable of rendering an account to himself and others, has no nous about the
matter?” (Note here that in Plato “having no nous” commonly means: having no
understanding at all, being completely confused.)
Lesher in “The Meaning of NOUS in the Posterior Analytics” rightly points out that
Aristotle drops Plato’s association of nous with apriority, instead returning to a much
older association of nous with perceptual insight. However, Lesher overlooks the
important aspect of continuity between Plato’s and Aristotle’s conceptions of nous that I
have indicated here.
68
demonstration, like syllogism, is concerned not with external but with internal discourse;
and it is always possible to object to the former, but not always possible to do so to the
latter . . . Definitions only need to be understood; and this does not constitute a
hypothesis, unless it is claimed that listening is a kind of hypothesis” (Posterior
Analytics, 76b); “With respect . . . to all things which are essences and actual, there is no
question of being mistaken, but only of thinking or not thinking them” (Metaphysics,
1051b). Fifth, and again accordingly, Aristotle frequently characterizes people who in
one way or another fail to affirm requisite first principles as thereby failing to mean
anything by their words, failing to think. For example, he says of people who attempt to
raise a question about whether nature exists at all: “It is necessary that the talk of such
people will be mere words, and that they will have no nous about anything” (Physics,
193a). Similarly, he dismisses the Platonists’ apparent assertion of the existence of
separate forms and denial of forms’ (in his view) evident immanence in substances with
the observation: “So goodbye to the Platonic forms. They are meaningless prattle, and if
they exist have nothing to do with our speech” (Posterior Analytics, 83a). Similarly, he
says that predecessors such as Empedocles and Anaxagoras “do not seem to know what
they say” because they do not base their conceptions of cause “on scientific principles”
(Metaphysics, 985a).
This account of Aristotle’s position requires one modest qualification. Aristotle
recognizes different degrees of misunderstanding and understanding, depending on the
exact nature of a failure to affirm requisite first principles. Thus whereas he dismisses the
people who try to treat nature’s existence as an open question and the Platonists with
their apparent claim that forms are separate as lapsing into sheer meaninglessness, he
rather says that Empedocles and Anaxagoras grasp the concepts of cause “vaguely . . .
and with no clearness” (Metaphysics, 985a), and more generally he describes the earliest
philosophy as “like one who lisps” (993a). Such a recognition that different degrees of
(mis)understanding occur is also implied when he holds that it is only via the
accumulation of sensory perceptions that a person arrives at a clear grasp of the universal
(i.e. the general concept and its definition), but also maintains that some sort of grasp of
the universal is already an essential part of sensory perception itself (Posterior Analytics,
100a-b: “the act of perception involves the universal”).70
Roughly speaking, though, Aristotle’s position is that, in close analogy to the global
situation that holds concerning the law of contradiction, but on a more local scale,
affirming the first principles that govern the subject matter of a specific science is
essential for really understanding the concepts involved there. A skeptic’s attempts to
question (or deny) such principles therefore doom him to meaninglessness and
thoughtlessness.71
70
In recognizing different degrees of understanding, among which some of the lower
degrees may occur even in the absence of a proper grasp of definitions, Aristotle’s
position is again strikingly continuous with Plato’s. As I have argued in “Socrates’
Demand for Definitions” and “Socrates’ Profession of Ignorance,” Plato, having at first,
in the early dialogues, treated understanding as an all-or-nothing matter requiring a grasp
of appropriate definitions, in the Meno came to recognize such differences of degree, as
part of his solution to the dialogue’s famous puzzle concerning the very possibility of
inquiry, and then in the Republic made that recognition an even more central feature of
his position (see e.g. his discussion in Republic, bks. 6 and 7 of the dianoia that
mathematicians can still have even though they lack definitions of their fundamental
mathematical terms). Note in this connection that Aristotle opens the Posterior Analytics
with an explicit discussion of the Meno’s puzzle about the very possibility of inquiry, in
the course of which he implies his commitment to the sort of Platonic position just
described as part of his own solution to the puzzle (71a-b).
71
The account that I have developed in this section of the article can be seen as a sort of
extended refutation of Burnyeat’s assertion at “Aristotle on Understanding Knowledge,”
Finally, it should be noted that this anti-skeptical strategy originally invented by
Aristotle went on after him to enjoy a very long and eminent career in philosophy. For
example, it is an important part of medieval Aristotelianism’s anti-skepticism,72 and it
reappears in one version or another in Spinoza,73 Hegel,74 and the Wittgenstein of On
Certainty.75 It is a strategy of considerable intrinsic philosophical importance.
*
Aristotle is also deeply concerned about the skeptical problem of concept-instantiation.
At Posterior Analytics, 89b he identifies the question of whether or not a concept has any
instances as one of the four types of question that interest inquirers, and he uses just the
sorts of examples that the Sophists Gorgias and Protagoras had used when posing such
concept-instantiation questions, namely mythological creatures and gods: “There are
other questions which take a different form: for example, whether a centaur or a god
136 that “when Plato and Aristotle say that epistêmê involves logos, neither of them
means logos to be an answer to skeptical doubt.” Aristotle, at least, does.
72
For instance, Aquinas writes in The Summa Theologica: “The intellect is always right
as regards first principles, since it is not deceived about them for the same reason that it is
not deceived about what a thing is. For self-known principles are such as are known as
soon as the terms are understood, from the fact that the predicate is contained in the
definition of the subject” (Basic Writings of Saint Thomas Aquinas, 184; cf. 544, 825-6).
73
For instance, Spinoza writes: “We doubt of the existence of God, and consequently of
all else, so long as we have no clear and distinct idea of God, but only a confused one.
For as he who knows not rightly the nature of a triangle, knows not that its three angles
are equal to two right angles, so he who conceives the Divine nature confusedly, does not
see that it pertains to the nature of God to exist” (Spinoza, A Theologico-Political
Treatise [New York: Dover, 1951], 270). Spinoza’s characteristic general fusion in his
concept of an “idea” of what we would think of as a concept with what we would rather
think of as an assertion embodies the same anti-skeptical strategy.
74
See my Hegel and Skepticism, esp. 123-4.
75
See my Wittgenstein on the Arbitrariness of Grammar, ch. 7.
exists. The question of existence refers to simple existence, and not to whether the subject
is (say) white or not.”76 Moreover, Aristotle goes on at 92b to note that it is possible for a
descriptive term to mean something even though it fails to pick out anything in existence:
a person “may know the meaning of [ti sêmainei] a phrase or of a name if, e.g., I speak of
a goatstag, but it is impossible to know what a goatstag is . . . Even non-existents can
have a significant name [sêmainein . . . esti kai ta mê onta].”
Aristotle is especially concerned with concept-instantiation questions in the Physics,
where he raises and discusses a whole series of them – in particular, concerning the
concepts of place (208a), void (213a), and time (217b). His treatment of the concept of
void is especially noteworthy, both because it concludes with a negative answer (in
reality there is no such thing as void), and because on the way to doing so it carefully
develops arguments on both sides of the question (in something very much like the
manner of the skeptical equipollence method). Indeed, these discussions of place, void,
and time in the Physics must surely be the ancestors of Sextus Empiricus’s strikingly
similar presentations of concept-instantiation problems concerning the same basic
concepts (as well as others).77
76
Concerning the probable echo of Gorgias and Protagoras in this passage: Just as
Aristotle here uses the example of a mythological creature, the centaur, to illustrate
failure of concept-instantiation, so in the version of Gorgias’s Concerning the Nonexistent or Concerning Nature that is preserved by Sextus Empiricus Gorgias uses the
example of two mythological creatures, the Chimera and Scylla, to illustrate it. (It may
also be worth noting that the other version of the same work that has come down to us
occurs in a putatively Aristotelian text: On Melissus, Xenophanes, and Gorgias.)
Similarly, Aristotle’s second example, gods, echoes Protagoras’s famous profession of
agnosticism concerning the existence of gods.
77
The only important difference is that in setting out the arguments on both sides Sextus
does not in the end arrive at a resolution, as Aristotle does, but instead reaches
equipollence and therefore suspends judgment.
What is Aristotle’s solution to the concept-instantiation problem? One important part
of it, visible in the passages from the Physics just referred to, lies in his confidence that
individual cases can in the end be resolved by means of argument – that, for example, a
careful consideration of the arguments for and against can show that there is such a thing
as place but that there is not such a thing as void.
However, Aristotle also has a further and less obvious strategy for fending off at least
any radical version of the concept-instantiation problem. How does he hope to prevent
this problem from driving us into complete skepticism about the relation of our concepts
to reality? Well, one basic idea he has here is, roughly, that it is part of the very nature of
thought, and of the descriptive concepts or meanings that articulate it, that such concepts
or meanings apply to things, qualities, relations, etc. actually found in the world. That
descriptive language can only have a meaning in virtue of a correspondence with genuine
features of the world – indeed, the sensible world – is implied by the following passage
from De Interpretatione, 16a: “Spoken words are the symbols of mental experiences and
written words are the symbols of spoken words. Just as all men have not the same
writing, so all men have not the same speech sounds, but the mental experiences, which
these directly symbolize, are the same for all, as also are those things of which our
experiences are the images” (emphasis added). It is also implied by the following passage
from De Anima, 432a: “Since according to common agreement there is nothing outside
and separate in existence from sensible spatial magnitudes, the objects of thought are in
the sensible forms, viz. both the abstract objects and all the states and affections of
sensible things. Hence no one can learn or understand anything in the absence of sense,
and when the mind is actively aware of anything it is necessarily aware of it along with
an image.” Similarly, the famous conclusion of the Posterior Analytics describes in some
detail how general concepts, or “universals,” only come to be “present in the soul,” and
hence available for linguistic expression and thought, by first being perceived in the
world through the senses (100a-b).
At first sight, this position might seem inconsistent with Aristotle’s – surely wellmotivated – concession at Posterior Analytics, 92b that a term like “goatstag” can be
meaningful even though there are no goatstags in reality. However, it is really not. What
that concession really shows is instead merely that in its precise version Aristotle’s basic
position allows not only for direct but also for indirect instantiations of descriptive
concepts: The term “goatstag,” although it lacks any direct instances, can still have
acquired its meaning or concept in the general manner described by De Interpretatione,
De Anima, and the conclusion of the Posterior Analytics – namely, in virtue of the fact
that this concept and its associated image correspond in their form with the form of things
that actually exist in the world and are perceived through the senses. For, although there
are no goatstags in reality, there are both goats and stags, and we do have an
acquaintance with their forms in virtue of having encountered real instances of them
through the senses. Consequently, in the case of the term “goatstag” too the concept and
the image involved have a form that is ultimately resolvable into forms of really existing
things acquired by us through the senses. Another of Aristotle’s examples of an empty
concept that was already mentioned above, “centaur,” obviously lends itself to the same
sort of account, being analyzable as: creature with the fore-parts of a man and the hindparts of a horse. And that this is indeed Aristotle’s general approach is strikingly
confirmed by his treatment of the one theoretical concept which he clearly identifies as
lacking any instances: void. For in the course of arguing in the Physics that the concept of
void has no instances, he explicitly provides an analysis, indeed a whole series of
analyses, of it into concepts that are instantiated: “But what those who believe in the void
really mean by the word is ‘dimensional interval without any substance perceptible to the
senses occupying it’“ (213a); “To determine whether the void exists or not, we must
know what they who use the word really mean by it [ti sêmainei to onoma]. The current
answer is ‘a place in which there is nothing.’ . . . We may logically expand their
definition of the void as ‘that in which there is nothing that is either heavy or buoyant.’ . .
. This seems to be one conception of the void: ‘that which is empty of all tangible body.’ .
. . According to another representation, however, the void is ‘that in which there is no
concrete compositum uniting form and matter, or corporeal entity’“ (213b-214a). It
seems safe to say that Aristotle would feel bound to take precisely the same sort of line
concerning any other descriptive concept that turned out to be empty as well. For
example, if it had turned out that the concepts “god,” “place,” or “time” were empty (in
his view, it does not), then he would have felt bound to insist that insofar as these are
genuine concepts at all (rather than merely meaningless words), they too must be
analyzable into component concepts which do have instances.78
Aristotle’s position that meaningful descriptive terms necessarily correspond to kinds
of features that really exist either directly or indirectly (i.e. via an intermediate analysis,
as in the case of “goatstag”) explains why, as T.H. Irwin points out in his thoughtprovoking article “Aristotle’s Concept of Signification,” in Language and Logos, ed. M.
Schofield and M.C. Nussbaum (Cambridge: Cambridge University Press, 1982), Aristotle
commonly uses the verb sêmainein (roughly, “to signify”) with an implication that
“names signify (sêmainein) essences and essences are not meanings, but belong to nonlinguistic reality; Aristotle thinks they are real features of the world, though not separate
from particulars” (246), whereas at other times he uses the same verb of terms which
correspond to no essence, such as the term “goatstag,” and in a way that implies that what
is signified is not so much features of the world as thoughts (255 ff.).
78
Aristotle’s reply to the skeptical problem of concept-instantiation therefore concedes
that individual descriptive concepts may lack any instances in the world, but insists that
this can only happen to the extent that they are compounded from more fundamental
descriptive concepts which do have instances. Consequently, if a skeptic raises a doubt
about whether some particular descriptive concept has any instances (e.g. Protagoras
concerning the concept “god”), Aristotle will reply to him that it is in the very nature of
concepts that if it does not, then it must at least be analyzable into component concepts
which do. And if a skeptic raises a doubt about whether any of our concepts have any
instances (as Gorgias in effect had), then a similar response will dispose of that worry
entirely.
It has sometimes been pointed out in the secondary literature that Aristotle does not
distinguish sharply between meaningful language and the features of reality that it is
about (as we would tend to do). For example, Andreas Graeser writes: “[Aristotle] had no
conception of language apart from the sorts of things that significant words were
supposed to mean. He did not distinguish systematically between linguistic questions on
the one hand and ontological questions on the other. In regard to words, he was interested
On the basis of these two different uses of the verb by Aristotle, Irwin himself
distinguishes between two different senses that he thinks it bears in Aristotle: terms
“signify” thoughts in one sense of “signify,” and by doing so are (sometimes) also able to
“signify” existing things in another sense of “signify” (256). And Irwin holds that for
Aristotle, while the signification of things cannot take place without the signification of
thoughts, the latter can take place without the former, as in the case of “goatstag” (2568). However, this interpretation seems to me quite misleading in that it (1) obscures the
intimacy of the connection between the two senses of sêmainein (if, indeed, one can even
properly speak of two different senses here at all), and in particular, (2) implies a sort of
autonomy of the “signification” of thoughts from the “signification” of things, and
primacy of the former over the latter, which Aristotle is in fact strongly concerned to
deny. For it is not only the case, according to Aristotle, that a signification of things
requires a signification of thoughts, but also that a signification of thoughts requires a
signification of things, namely either a direct or an indirect one.
in them only in so far as they stand for things-that-are (onta) . . . For Aristotle, language
was indeed Seinssprache and it was considered to mirror relations that obtain between
real entities existing independently from the mind.” 79 The points that I have made above
suggest that this is in a sense quite correct, but that it also needs to be understood in one
particular way rather than another. Someone could, after all, properly say something quite
similar to what Graeser says here about Aristotle concerning Herodotus, who likewise
tends to assume that if there is a meaningful descriptive word in use, then there must be
some corresponding feature of reality that it picks out – and who, for example, therefore,
in his investigations of the various non-Greek communities around the Mediterranean,
feels compelled whenever he encounters some new name for a god either to posit the
existence of a new god or to identify the name’s referent with some god already known to
the Greeks or (a characteristically Greek third alternative that seems strange to us) to do
something between those two things and say that the referent is, for example, “the
Theban Zeus,” but never even considers, as we would, the further possibility that the
name might simply have no referent at all. However, whereas Herodotus’s conception of
language as in this way a sort of Seinssprache is naïve, Aristotle’s is not. Instead,
Aristotle’s corresponding conception is a sophisticated reaction against earlier attempts
by Sophists (and perhaps others) to divorce meaningful descriptive language from reality,
and on the basis of doing so to raise skeptical problems.
Let me pursue this whole side of Aristotle’s response to skepticism just a little further,
though. The anti-skeptical implications of Aristotle’s theory of the nature of descriptive
A. Graeser, “On Language, Thought, and Reality in Ancient Greek Philosophy,”
Dialectica, 31/3-4 (1977), 373. (I take it that Graeser’s reference to “relations” in the last
sentence is an inadvertent overspecification, rendering his point more restricted than he
really means it to be.)
79
concepts or meanings were later recognized by Descartes, who appealed to precisely such
a theory (presumably borrowed from more contemporary Aristotelians)80 as part of his
response to dream-skepticism in the First Meditation (only, though, subsequently to
sweep it aside by means of the hypothesis of an evil genius in his next wave of skeptical
argument): “Well, suppose I am dreaming, and these particulars, that I open my eyes,
shake my head, put out my hand, are incorrect, suppose even that I have no such hand, no
such body. At any rate it has to be admitted that the things that appear in sleep are like
painted representations, which cannot have been formed except in the likeness of real
objects. So at least these general kinds of things, eyes, heads, hands, body, must be not
imaginary but real objects . . . Even if these general kinds of things, eyes, heads, hands,
and so on, could be imaginary, at least it must be admitted that some simple and more
universal kinds of things are real, and are as it were the real colors out of which there are
formed in our consciousness all our pictures of real and unreal things. To this class there
seem to belong: corporeal nature in general, and its extension; the shape of extended
objects; quantity, or the size and number of these objects; place for them to exist in, and
time for them to endure through; and so on.”81
Now it might seem that Aristotle’s theory about the nature of descriptive concepts or
meanings constitutes only a rather weak response to the skeptic. For an equipollence
skeptic might reply, “Well, this theory is interesting enough, but I have an alternative
It has been plausibly suggested that Descartes’ study at La Flèche had exposed him to
Aristotelian anti-skeptical arguments. See Popkin, The History of Skepticism from
Erasmus to Spinoza, 173.
81
Descartes: Philosophical Writings, ed. E. Anscombe and P.T. Geach (London:
Nelson’s University Paperbacks, 1971), 62-3. Descartes envisages this reply to dreamskepticism as not only seeming to secure the island of truths that he lists here itself
(which is our main concern), but also seeming thereby to secure the basis of
mathematical knowledge.
80
theory of the nature of descriptive concepts or meanings which does not carry any such
anti-skeptical implications, and which I shall now set over against it and bring into
equipollence with it . . .” And a Cartesian skeptic might reply, “Yes, it’s an interesting
enough theory, but I cannot rule out all possible grounds for doubting it, I cannot be
certain that it is correct, and so, by my skeptical principles, I must withhold assent from it
. . .” Indeed, this is in effect what the Cartesian skeptic does say in response to it in the
First Meditation; he draws attention to the possibility that an omnipotent God or evil
genius might be giving him even his most fundamental descriptive concepts without their
corresponding to anything in existence, and that the Aristotelian theory might therefore
be false: “But there has been implanted in my mind the old opinion that there is a God
who can do everything . . . How do I know that he has not brought it about that, while in
fact there is no earth, no sky, no place, yet all these things should appear to exist as they
do now?”82
However, I want to suggest that Aristotle’s position in fact already has a feature built
into it that promises at least some protection against such a skeptical counterattack.
Recall Aristotle’s general doctrine (discussed earlier) that belief in certain fundamental
principles is a necessary condition of even understanding corresponding concepts. In
keeping with that general doctrine, Aristotle might with at least some plausibility argue
that in order even to have a (clear) concept of concepts, meanings, or thoughts, one must
recognize the fundamental aspect of their nature to which his theory draws attention, so
that to the extent that a skeptic attempted to suspend judgment about (or to deny) the
theory, he would ipso facto evince a failure even to grasp the very concept of concepts,
82
Ibid., 63-4.
meanings, or thoughts, and his apparent suspension of judgment about (or denial of) the
theory would in fact only be an illusion of such, he would in reality be failing even to
understand it, and so not suspending judgment about (or denying) it but merely exhibiting
mental confusion. Indeed, I suggest that just such a position is actually visible in
Aristotle’s rejection (quoted earlier) of the Platonic theory of separate forms, with its
denial that forms inhere in sensible substances, as meaningless: “So goodbye to the
Platonic forms. They are meaningless prattle, and if they exist have nothing to do with
our speech” (Posterior Analytics, 83a).
Like the anti-skeptical strategy I attributed to Aristotle in the previous section, the antiskeptical strategy I have attributed to him in this section – one might call it a strategy of
making ontology prior to semantics – has proved of enduring appeal to anti-skeptical
philosophers, and is of considerable intrinsic importance. For example, it went on to play
a significant role in the medieval and early modern Aristotelian tradition that Descartes
was echoing in the First Meditation, and more recently Donald Davidson’s approach to
forestalling skepticism and other subversive epistemologies (e.g. conceptual relativism)
deploys a strikingly similar strategy, to the extent that it too seeks to achieve that goal by
insisting that any ascription of meanings to people must proceed via, and be constrained
by, a prior determination of how the extra-semantic world is.83
In sum, it seems to me that the Hegelian thesis that every genuine philosophy has a
skeptical side in fact holds up very well when confronted with what might initially look
Davidson’s two most relevant articles in this connection are “On the Very Idea of a
Conceptual Scheme” and “A Coherence Theory of Truth and Knowledge.” For some
discussion of similarities between his approach and Aristotle’s see my “On the Very Idea
of Denying the Existence of Radically Different Conceptual Schemes,” Inquiry, 41/2
(1998).
83
like the most impressive counterexample to it from the ancient world, namely Aristotle’s
philosophy.84 Indeed, far from being embarrassed by this seeming counterexample,
Hegel’s thesis, along with some of his more specific insights about Aristotle, lead
towards a deeper appreciation of the real character of Aristotle’s position.
*
So much by way of a case for the plausibility of the Hegelian thesis in connection with
ancient philosophy. But what about modern philosophy? The thesis seems to me
plausible in this connection too (though here my case will have to be briefer).
For example, we usually classify as “philosophy” both the broadly skeptical positions
of Montaigne, Bayle, and Hume and the broadly anti-skeptical positions of Descartes,85
84
As I have tried to show by means of the occasional footnote and remark during the
course of this article, the same is also true of another seeming counterexample intimately
related to that one: medieval and early modern Aristotelianism. Like Aristotle himself,
this Aristotelian tradition in fact incorporates a range of anti-skeptical doctrines into its
position, doctrines that were first used for anti-skeptical purposes by Aristotle himself
and then borrowed from him by the tradition. In making this side-point about the later
Aristotelian tradition I have been helped by an excellent paper that Dominik Perler
presented at the same Heidelberg conference as the present one: “What Makes Radical
Doubts Possible? The Metaphysical Background to Skeptical Debates in the Later Middle
Ages.” In his paper Perler argued convincingly that medieval philosophers failed to dwell
on skepticism in the way that early modern philosophers do, not (as has often been
supposed) because they were unaware of it, but because they believed that they possessed
a range of metaphysical doctrines which forestalled it. Perler in particular cited Aquinas
(along with Buridan) as an example of this.
85
Two studies which convincingly demonstrate the seriousness of Descartes’ antiskeptical intentions are Popkin, The History of Skepticism from Erasmus to Spinoza, esp.
ch. 9 and E.M. Curley, Descartes against the Skeptics (Cambridge, Mass.: Harvard
University Press, 1978). A more recent revisionist reading of Descartes – found above all
in D. Garber, Descartes’ Metaphysical Physics (Chicago: University of Chicago Press,
1992) and S. Menn, Descartes and Augustine (Cambridge: Cambridge University Press,
1998) – tends to downplay or even deny Descartes’ interest in answering skepticism,
Berkeley, Kant, G.E. Moore, and the later Wittgenstein. But we do not normally classify
as “philosophy” the neither deeply skeptical nor deeply anti-skeptical religion of
Luther,86 or the neither deeply skeptical nor deeply anti-skeptical natural science of
Newton.87
Moreover, as in the case of Aristotle, many paradigmatic modern philosophers who
might initially look like plausible counterexamples to the thesis quickly turn out not to be
on closer inspection. For instance, Spinoza might appear to be a counterexample. But in
fact, it turns out that, in keeping with his Cartesian heritage, Spinoza was quite deeply
concerned to defeat skepticism – in particular, by arguing that a skeptic’s attempt to
question such fundamental theses as that God exists or that the internal angles of a
triangle equal the sum of two right angles would inevitably reduce him to mere
instead arguing that for Descartes radical doubt serves as a sort of conceptual tool for
achieving such other goals as undermining reliance on the senses, arriving at a novel
scientific conception of the physical world, and establishing the priority of knowledge of
oneself and God over knowledge of the physical world. This revisionist reading seems to
me correct in its positive claims, but incorrect in its downplaying or denial of the
importance for Descartes of answering skepticism. The two projects are in fact perfectly
compatible, and Descartes combines them.
86
The qualification “deeply” is required here. Luther did famously combat Erasmus’s
sympathy with skepticism (replying censoriously, “Spiritus sanctus non est scepticus”).
However, Luther’s response was superficial. Concerning the character of his response
and its superficiality, see Popkin, The History of Skepticism from Erasmus to Spinoza, 58.
87
Newton is an interestingly complicated case, though. Skepticism, in particular
Pyrrhonism, may in fact originally have played a significant role in motivating his
scientific method in the sense that it was largely the need to reply to Pyrrhonism that had
motivated scientifically minded predecessors such as Mersenne and Gassendi earlier in
the seventeenth century to suspend judgment about the underlying real natures of things
and instead seek an optimal account of the appearances, an approach which subsequently
became Newton’s own (see on this Popkin, The History of Skepticism from Erasmus to
Spinoza, esp. 145-6). However, to judge from Newton’s credulity about the Bible, about
alchemy, etc., it seems that this original deep concern with skepticism and with
combating it had more or less evaporated by the time he inherited the approach in
question.
babbling.88 Again, the Scottish commonsense philosophers – Reid, Beattie, et al. – might
be proposed as counterexamples. However, on closer inspection, they were largely
motivated by a desire to counter the sorts of skeptical challenges to knowledge that Hume
and others had mounted. Again, several influential German interpreters (e.g. Heimsoeth
and Heidegger), and even a few Anglophone interpreters (e.g. Graham Bird and Karl
Ameriks), have seen Kant as basically uninterested in skepticism. But in fact, as most of
the Anglophone Kant literature has long recognized, and as I have recently argued in
detail as well,89 that interpretation turns out to be massively mistaken. Again, an old
reading of Hegel himself interprets him as a philosopher who was uninterested in
epistemology generally and skepticism in particular (such a reading is found in J.B.
Baillie and more recently in Roger Scruton, for instance). But new work on Hegel,
including some of my own,90 has shown this reading to be radically mistaken too.
What about modern formal logic, philosophy of language, philosophy of science,
philosophy of mind, and so on? These areas do indeed challenge the Hegel-inspired
thesis, but they hardly refute it. Concerning formal logic, this area of philosophy may
well originally have had anti-skeptical roots, for as Friedrich Schlegel pointed out,
Aristotle’s version of it was probably in large part motivated by an ambition to overcome
the epistemologically subversive arguments of the Sophists.91 Moreover, I would
tentatively suggest that Frege’s revolutionary recasting of formal logic in the second half
of the nineteenth century was probably in part catalyzed by Schlegel’s, C.G. Bardili’s,
and Hegel’s shared recognition earlier in the century that classical logic was vulnerable to
88
See Popkin, The History of Skepticism from Erasmus to Spinoza, 238 ff.
See my Kant and Skepticism.
90
See my Hegel and Skepticism and Hegel’s Idea of a “Phenomenology of Spirit,” ch. 3.
91
See Schlegel’s Cologne lectures on philosophy from 1804-6.
89
skepticism, and by Bardili’s and Hegel’s consequent attempts to recast logic in order to
make it invulnerable to skepticism.92 In addition, it should be noted that the inclusion of
formal logic as it is usually practiced today within philosophy might be questioned; it
might rather be classified as part of mathematics, or as a discipline unto itself.
Concerning philosophy of language, the prospects of defending the Hegelian thesis again
seem bright. For example, it is a striking fact that several leading modern philosophers of
language whose preoccupation with skepticism may not initially have been apparent in
their work revealed their anti-skeptical motives later on – as Wittgenstein did in On
Certainty and Donald Davidson did in “On the Very Idea of a Conceptual Scheme” and
“A Coherence Theory of Truth and Knowledge.” Concerning philosophy of science, this
area of philosophy quite often has recognizable skeptical or anti-skeptical motives – for
example, instrumentalist programs in philosophy of science are often motivated by a
concern to cope with skepticism concerning claims about entities and facts that transcend
experience. In other cases work in this area might naturally be re-classified as something
other than philosophy (e.g. as part of a scientific discipline or its methodology).
Concerning philosophy of mind, much recent work in this area has been motivated by an
ambition to overcome skepticism, especially skepticism about other minds – as in the
case of Wittgenstein, for example, who was eventually led towards a form of behaviorism
by the ambition to overcome this sort of skepticism.93 On the other hand, some recent
Concerning the Schlegel-Bardili-Hegel position, see my “Schlegel and Hegel on
Skepticism and Philosophy,” Hegel and Skepticism, ch. 1, and Kant and Skepticism, ch.
12. I hope to develop this novel hypothesis about Frege in future work. For now I merely
mention the fact that Schlegel and Hegel developed their position while working in Jena,
the same town that Frege later lived and taught in.
93
For an excellent account of Wittgenstein’s philosophy of mind in its various phases,
see P.M.S. Hacker, Insight and Illusion (revised edition, Bristol: Thoemmes, 1997).
92
work in this area, such as connectionist and modular theories of the mind, might be better
re-classified not as philosophy but as science (or perhaps pseudo-science). Concerning all
these areas, it should also be noted that the Hegelian thesis need not imply that everything
in genuine philosophy is either skepticism or anti-skepticism; the thesis can leave plenty
of room for other issues as well.
*
Finally, what should one to say about non-western philosophy, in particular Indian and
Chinese philosophy? Does this not constitute a counterexample to the Hegelian thesis?
Here I will have to be even more brief. But, broadly speaking, it seems to me attractive
to draw a distinction between different types of non-western thought, and to handle them
differently. On the one hand, there is Buddhism, which is in fact heavily involved in
developing and responding to skeptical problems, and therefore constitutes a good
candidate for the status of genuine “philosophy.”94
On the other hand, there is also the sort of more straightforward formulation of
politico-ethical or religious precepts that is found, for example, in Confucius. Insofar as
this is neither skeptical nor deliberately anti-skeptical, it is probably better classified, not
as “philosophy,” but rather as something else (Passmore has helpfully suggested
“wisdom”).
*
94
It has, indeed, been argued with some plausibility that ancient Pyrrhonian skepticism
originally had Buddhist roots. See E. Flintoff, “Pyrrho and India,” Phronesis, 25 (1980).
In sum, the Hegelian thesis is a very plausible one. It is defensible in relation to ancient
philosophy, modern philosophy, and non-western philosophy. In some cases, such as
Aristotle, it indeed leads to the discovery of deep motives in a philosopher that might
otherwise be overlooked. It is deeply illuminating as an account of the nature of
philosophy as a whole.95
95
I would like to thank the following people for stimulating discussions which helped me
to develop this article in various ways: Paul Franks, Hans Friedrich Fulda, Markus
Gabriel, Leo Groarke, Katia Hay, Sebastien Luft, Al Martinich, Dominik Perler, David
Sosa, Klaus Vieweg, Michael Williams, and Paul Woodruff. I would also like to thank
broader audiences at the following institutions for thought-provoking discussions which
helped me to develop it: Heidelberg University (where it was first presented), Marquette
University, and the University of Texas at Austin.