Understanding Quine in Terms of Aufbauian Reductionism:
Another Look at Naturalized Epistemology
S. Rocknak
Hartwick College
Oneonta, NY USA
True to at least Burton Dreben's word, lifelong friend and student of Quine, it is simply intellectually and
historically irresponsible to attempt to understand Quine’s work apart from Carnap’s. 1 In fact, it could
even be said that Quine's dedication of his first major epistemological undertaking to Carnap as his
"teacher and friend" (Word and Object (1960)) was a far stretch more than a polite gesture; it might even
be ventured that without Carnap, there might not have been a Quine. Or at the very least, Quine as we
know him. In fact, as if to underline this very point, Quine writes in his short essay "Homage to Rudolph
Carnap" (1970) that: "Carnap was my greatest teacher … I was his disciple for six years. In later years his
views went on evolving and so did mine in divergent ways. But even where we disagreed he was still
setting the theme; the line of my thought was largely determined by problems that I thought his position
presented." 2 And these problems, at their most general level, revolved around what Russell once gave the
title of a book: Our Knowledge of the External World (1914). For the fundamental questions that initially
drove Russell, then Carnap, and eventually Quine, were simple, although admittedly perplexing: What
does our knowledge3 of the external world consist of and how does one acquire it? In what sense is it
certain, and/or justifiable, if at all?
1 Dreben emphasized this point repeatedly in the 1993 Carnap/Quine seminar that I regularly sat in on at Boston University.
Also see his paper "Quine" (1990), where he stresses the Carnap/Quine relationship.
2 (WOP 41). For more on Quine’s thoughts on Carnap see at least: all of Dear Carnap, Dear Van; The Quine-Carnap
Correspondence, all of From A Logical Point of View, "The Lectures on Carnap" (1934) (DCDV), "Truth by
Convention,"(1936) (WOP), "Notes on Existence and Necessity" (1956) (SPL) (this last essay was translated from parts of the
book O Sentido da nova logica (1944), and eventually, was rewritten into "Reference and Modality," which can be found in
From A Logical Point of View). "On Carnap's Views on Ontology," (1951) (WOP),"Carnap and Logical Truth" (1954) (WOP),
The Time of My Life, (1985), "Carnap's positivistic travail" (1985), "Carnap," (1987), "Two Dogmas in Retrospect," (1991), “In
Praise of Observation Sentences,” (Appendix), (1993), "In Conversation: W.V. Quine (video)," (1994) and all of From Stimulus
to Science (1995).
3 It should be noted that Quine thought that we should “give up the notion of knowledge as a bad job and make do rather with
its separate ingredients.” (Q, 109). For the most part, Quine’s rejection of knowledge has to do with his rejection of “certainity,”
a notion that I touch on at the end of this paper. However, for our purposes, it is enough to realize that when Quine speaks of
1
However, in this essay I certainly cannot explain how Carnap influenced Quine in regard to these
matters in any degree of comprehensive detail—that would take a book. So instead, I focus on explicating
a small portion—particularly, a third—of what I claim is the central tension between these two
philosophers, namely, one of Quine’s reactions to the three fundamental epistemological circles he
believed to be present in Carnap’s work, or what I think we may characterize as three contemporary
variants of Meno’s Paradox.4 More specifically, I focus here on what we may identify as the first circle:
[1] The “rational reconstruction” (LAW 158) of knowledge in the Logische Aufbau der Welt, where
knowledge seems to paradoxically emerge from knowledge, where the latter, more primary mode of
knowledge consists of “elementary experiences,” the relation R of “remembering as similar” and Russell
and Whitehead’s theory of relations. Meanwhile, if only to frame our discussion in terms of Quine’s more
comprehensive reaction to Carnap, realize that the other two circles are: [2] “The linguistic doctrine of
logical truth,”5 or in other words, Carnap’s conventional doctrine of logical truth, as spelled out in the
Logical Syntax of Language. For according to Quine, as well as any of those who wrestled with the
“logocentric predicament,” 6 on this account, we seem to have to already know logic to acquire logic; in
particular, in order to accept a logical inference as logically valid, one must presuppose the validity of that
very inference.7 [3] Carnap’s brand of analyticity, which is not be confused with the linguistic doctrine of
“knowledge” he is speaking of beliefs (from a behavioristic point of view), where some are true, some are justified, and some
are believed in more than others: “We can still speak of a belief as true, and one belief as firmer or more certain, to the
believer’s mind. There is also the element of justification, but [there are] … limitations.” (Q, 109).
4 Recall that in its original sense, the paradox unfolds as follows: How may we learn, look for, or acquire knowledge if we don't
already know what it is we want to learn, look for, or acquire? Otherwise, how could we identify what it is we want to know
when we stumble across it? This is the first “horn” of the paradox. But if we already knew what we were after, why bother?
This is the second “horn” of the paradox. In short, the epistemological puzzle is: Some thing or event X may not be known (and
thus, be defined as such, for in order to define X, one must know X), unless one already knows X. But if one already knows X,
one would not seek to know X. See M 80d-e.
5 See Quine’s "Carnap and Logical Truth" (1954) (WOP 108), where he introduces this term.
6 Dreben reminds the reader in "Quine" that Sheffer had been at odds with this problem as early as 1926 in his Review of
Principia Mathematica, where he specifically identifies this problem as the “logocentric predicament.” However, realize that
Lewis Carroll had put his finger on this problem (although somewhat playfully) as early as 1895 in “What the Tortoise Said to
Achilles.”
7 In this regard, Quine writes in “Carnap and Logical Truth:” “It is impossible in principle, even in an ideal state, to get even
the most elementary part of logic exclusively by the explicit application of conventions stated in advance. The difficulty is the
vicious regress, familiar from Lewis Carroll which I have elaborated [on in "Truth by Convention"]. Briefly the point is that the
logical truths, being infinite in number, must be given by general conventions rather than singly; and logic is needed then to
begin with, in the metatheory, in order to apply the general conventions to individual cases.” (p. 115). Or, as Barry Stroud
(1995) explains it: "The trouble here (making a long story short) is that there is no limit to the number of logical truths, so it
would be a never-ending task to declare each of them true by fiat, one by one. The 'conventions' therefore must be general, and
2
logical truth. For as Quine points out in a number of papers and letters to Carnap, 8 and most famously in
“The Two Dogmas of Empiricism” (1950), it seems that to define analyticity, one must already have some
definition of analyticity in mind, and so, correspondingly, to know what ‘analyticity’ means in terms of
grasping it by way of its definition, we must already know what ‘analyticity’ means.
However, as noted above, as interesting as it would be to examine circles [2] and [3] in more
depth, time and space simply do not permit. As a result, I focus on just circle [1] here, namely, the paradox
of reductionism. To do so, I have divided this paper into five sections: In §1, I sketch the general structure
of the reductionist project as it is presented in the Aufbau. In §2, after canvassing the distinction between
what Quine characterizes as “radical” reductionism (namely, Aufbauian reductionism; FLPV; TDE 39) v.
“attenuated” reductionism (namely, the idea that the truth value of a sentence can be determined purely by
empirical means; FLPV; TDE 41), I explain why Quine thought the Aufbau was flawed. In particular, I
begin by examining his criticism that it smacked of “mentalistic monism” (FSS 15). Following, I show
that in virtue of this critique, Quine puts his finger on—however implicitly—the epistemological
circularity of the “radical” reductionism of the Aufbau, which, I claim, reminds us of the second horn of
Meno’s Paradox.
However, in §3, I point out that this breed of epistemological circularlity is not be confused with
what we may characterize as the “naturalistic circle—“ where it is alleged that using the scientific method
to examine science is problematic—in two fundamental respects, where the first problem was brought into
focus by Hume,9 and the second, by “physicalism,” particularly, Quine’s notion of physicalism. These
circles are, respectively: a.) Science may only yield fallible results and so, if the claim “We must use
science to examine science” is a scientific claim, it is a fallible claim. As a result, the empiricist, or in
other words, the naturalized philosopher, appears to be undermined from within. b.) The epistemological
then logic will be needed to infer particular logical truths from the general 'conventions.' If nothing were logically true
independently of our adopting certain 'conventions' there would be no way of generating all logical truths from 'conventions' we
might adopt" (38-39).
8 See “Truth by Convention” (1935) (WOP), and letter #97, Jan 1, 1943 (DCDV 296-297). See also White (1950), which came
out the same year that Quine delivered “The Two Dogmas of Empiricism” at an APA meeting.
9 Yet as Quine points out, this circle was acknowledged even in ancient skepticism (RR 2-3). However, it might be argued that
it was Hume who pushed this seemingly paradoxical mode of thinking to its limit (c.f. Husserl; C 89-90). Moreover, Quine
explicitly attributes this circle to Hume in his 1946 lectures on Hume (see Pakaluk, pp. 455, 457 (#490) 459 (#500)).
3
foundations of science are, according to contemporary scientific research itself, overwhelmingly sparse,
consisting of unrelated sense data manifest by certain sets of nerves firing. Consequently, if it is shown
that scientific theory is equivalent to such scanty data as a result of reducing science to it, then our
scientific claims seem to be equally scanty; they amount to nothing more than intermittent and unrelated
sets of nerves firing.
Subsequently, in §§4-5 I show that Quine’s repudiation of “radical” reductionism, in light of its
paradoxical nature (in a respect reminiscent of the second horn of Meno’s Paradox) could only have
motivated Quine to adopt naturalism for reasons that appear to be independent of his pragmatic concerns,
simply because it is not reasonable (namely, it is paradoxical)10 to adopt a Carnapian
phenomenalistic/mentalistic approach to epistemology. Armed with what could only be his invigorated
faith in the naturalistic method, he was then, as I see it, equipped to break the physicalistic version of the
naturalistic circle, a repudiation that, I show, entails his rejection of “attenuated” reductionism and
concomitantly, his rejection of “analyticity” if not “certainty” altogether. As such, the Humean version of
the naturalistic circle could simply be dismissed. Meanwhile, the practicality of an admitably fallible
science could be unashamedly embraced, although not just for the sake of its practicality—as Quine
himself seems to misleadingly indicate throughout his work—but instead, as just noted, to avoid the
seemingly Platonic paradox of Aufbauian reductionism.
10 In this respect, it may seem, on the face of it, that I am taking issue with Fogelin (2004) where he argues that according to
Quine, “epistemology does not provide an independent standpoint for empirical science.” (19) Rather, Fogelin continues,
“empirical science provides the framework for understanding empirical knowledge, including the empirical knowledge
provided by empirical science.” (19) However, I completely agree with Fogelin if the word ‘naturalized’ is inserted before the
word ‘epistemology’ in the first sentence cited above. Yet non-naturalistic epistemology, namely an epistemology that seems to
embrace the centrality of reason, where such reason is, it would seem, so removed from empirical revision that it seems immune
to revision—and as such, is not a priori, and thus, does not, according to Quine, constitute a dreaded “first science”—does, I
argue above, seem to provide a somewhat “independent standpoint for empirical science,” or at the very least, a somewhat
independent justification for empirical science. I say “somewhat,” for as just noted, although according Quine reason seems to
be central to not just scientific inquiry, but to all human inquiry, it is nevertheless, not immune to revision, and thus, not a
priori (see my brief discussion of “analyticity” in §§4-5 for a bit more detail). In fact, Fogelin clearly acknowledges Quine’s
inadvertent appeals to reason at the very end of his essay, although I think that Fogelin misleadingly characterizes such appeals
as Quine’s latent dependence on a priori rules: “But alas, Quine was not as fully committed to a naturalistic standpoint as he
might have been … [in particular] he tended to move at a very high level of theoretical generality, rarely touching down at
empirical checkpoints. He often seemed more concerned with the relationship between his philosophical position and the
philosophical positions of others than with the relationship between his position and the data need to support it. As a result,
contrary to Quine’s stated intentions, his theory sometimes looks more like ‘an a priori propadeutic or groundwork for science’
(NK 126) than like science itself.” (45)
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§1 The Aufbau: a General Overview
As noted above, and as Quine rightly sees it throughout his work and his letters, 11 the early Carnap was
the champion of the great Russellian project in Our Knowledge of the External World, which was,
according to Quine, the explication of the "construction" of the external world from bits of sense data.
(TT; ROD 83) In Carnap's case in the Aufbau, this consisted of “attempt[ing] to apply the theory of
relations to the task of analyzing reality.” (LAW 7) That is, as noted earlier, for his method of
construction, Carnap employs the theory of relations as it was laid out by Russell and Whitehead in the
Principia. Broadly speaking, this means that Carnap attempted to show that all concepts/objects12 may be
understood as logically "reducible," or translatable13 to the primary relation “remembering as similar” (or
what we may also refer to as R in this paper) and certain unanalyzable “elementary experiences” (or what
we may also refer to as E in this paper) (see LAW Chapter C).14 In this respect, Carnap hoped to
11 See at least "Russell's Ontological Development," (1981), (TT 84), "Homage to Rudolf Carnap," (1970) (WOP 40), and
letter #37, Quine to Morris (1936) (DCDV 204-206), and (FSS 9-10). See also Richard Creath’s comments in his Introduction
to Dear Carnap, Dear Van, particularly: "Russell called for the rational reconstruction of our knowledge on the basis of sense
experience and urged the narrowest and deepest selection of concepts [in Our Knowledge of the External World]. It seemed to
speak directly to Carnap. In fact [Carnap] penciled in the margin of his copy 'This narrowing and deepening of the fundamental
postulates is my task!'" (DCDV 24).
12 Note that according to Carnap, there is no logical difference between concepts and objects. Rather, this difference is, at best,
a psychological difference, and so, for the purposes of the Aufbau’s program, may be ignored (LAW 10). However, it should be
pointed out that the object that the concept may be understood as, is not to be confused with the object that may fall under the
concept: “it follows that to only one concept there belongs one and only one object ‘its object’ (not to be confused with the
objects that fall under the concept”(LAW 10)
13
Note the following passage where Carnap makes it quite clear that at least in principle, all knowledge may be translated into
elementary experiences and R (where here, he is concerned with making it clear that by doing so, he may also account for the
objectivity of knowledge): “Even though the subjective origin of all knowledge lies in the contents of experiences and their
connections, it is still possible, as the constructional system will show, to advance to an intersubjective, objective world, which
can be conceptually comprehended and which is identical for all observers” (LAW 7; emphasis added). That is, important for us
to note, “all knowledge” is contained it, or in other words, “lies in” E and R.
14 According to Carnap, our “elementary experiences” must be understood as "wholes," as opposed to "atomistically," where,
according to Carnap, such “atoms” are bits of unrelated sense data. As such, Carnap claims that by definition, these elementary
experiences are unanalyzable. Thus, they do not display "any constituents or properties or aspects." (LAW 110). Carnap writes
in further explanation: "In opposition to the 'atomizing' school of thought in psychology and epistemology, which postulates
such psychological 'atoms,' as e.g. simple sensations as elements, there is presently more and more emphasis on the fact that
'every state of consciousness is a unit and is not, strictly speaking, analyzable.'((Schlick, Erkenntnis.) 143f., italics added). In
particular, there is more and more proof that, in perception, the total impression is primary, while sensations and particular
feelings etc., are only the result of an abstracting analysis" (LAW 108). Carnap refers to the following philosophical works to
support this claim: Wilhelm Schuppe: (1894); 2nd ed., 1910. Hans Cornelius, (1911); 2nd ed. 1919. Heinrich Gompenz, (1901);
119 (1902) and Robert Reniger, (1911). And he refers to work done by the following psychologists as well: Wolfgang Köhler,
(1925) and Max Wertheimer (1925).
5
"rationally reconstruct" the concepts of all fields of knowledge (including science) by showing that they
may be translated into the strictly formal world of a "constructional language." As such, this constructed
language served as a model for how all fields of knowledge may be redefined, or in other words, logically
reduced to R and elementary experiences.15
In a bit more detail—although it is not relevant to indulge ourselves in all the Aufbau’s technical
machinery here—as far as reducing concept/objects to other concept/objects goes, and conversely,
constructing concepts/objects out of other concepts/objects, Carnap explains that:16
if an object a is reducible to objects b, c, then all statements about a can be transformed into statements
about b, c. To reduce a to b, or to construct a out of b, c, means to produce a general rule that indicates for
each individual case how a statement about a must be transformed in order to yield a statement about b, c.
This rule of translation we call a constructional rule or constructional definition.” (LAW, 6)
That is, "construction rules" are the rules that allow us to change any statement about a into given
statements about b and c, provided that the concept/object a is "reducible to," namely, may be redefined as
the concept/objects b, c. For instance, Carnap points out further on in the Aufbau that we may "reduce"
the concept/object of a prime number to two other concept/objects, a natural number and division. As a
result, a definition that initially concerned just prime numbers (particularly, a, with b and c absent),
namely, "x is a prime number" (LAW 16) may be restated to concern only b & c: "x is a natural number
whose only divisions are 1 and x itself.” (LAW 16) Construction proceeds exactly opposite, more
specifically, if there is a statement about b and c and it can be translated into a statement about a, b, and c
15 Realize that Carnap never intended to complete this constructional system in the Aufbau, instead, he merely wanted to show
in what respect it was possible (LAW 176). Moreover, in Carnap’s words, “rational reconstruction” may, in its most general
sense, be understood as a formal clarification of what we do “intuitively,” or in other words: “The constructional system is a
rational reconstruction of the entire formation of reality, which, in cognition, is carried out for the most part intuitively. In
reconstructing the recognition of the plant, the botanist has to ask himself what, in the actual act of recognition, was really
perceived and what was the apperceptive synthesis [verarbeitung]? But these two components which are united in the result he
can only separate through abstraction. Thus, in rational reconstruction, construction theory has to distinguish, by means of
abstraction, between the purely given and the synthesis; this division must be made, not only for the individual case, but for the
entire conscious process.” (LAW 158)
16
Where an accurate “statement,” or as Carnap also puts it, an “definition” concerning a concept/object should be understood
as a knowledge claim (see LAW, Chapter A). Also note the following passage (which refers back to Chapter A): “[science] can
restrict itself to statements about structures, since all objects of knowledge are not content, but form, and since they can be
represented as structural entities (cf. §15 f)” (LAW 107). In other words, the “object” of knowledge in this case is a “structure,”
where the knowledge claim is the “statement” about that structure.
6
(where b and c may be absent), then the concept/object a is constructed. As a result, the construction of a
concept/object is actually a new definition of a concept/object via other concept/objects. Or as Carnap puts
it (where here, he uses the term ‘statement’ rather than ‘definition’): “An object (or concept) is said to be
reducible to one or more other objects if all statements about it can be transformed into statements about
those other objects ... [thus] if a is reducible to b, and b to c, then a is reducible to c. Thus, reducibility is
transitive.” (LAW 6) In short then, this constructing/reduction process is what Carnap also refers to as
“analysis” which, as such, is “analytic” in nature; as a result, any statements about concepts/object a—
where a is reducible to other concepts/objects b and c—are interchangeable with statements about b and
c.
Ultimately, as Carnap explains in Part III, Chapter C of the Aufbau, all basic concepts/objects may
then, by a method he calls “quasi-analysis,” (LAW §§69-74) be reduced to a network of “basic relations,”
(LAW 98) where, as noted earlier, the relation that is logically primary is R, or in other words,
“remembering as similar” and the components that these relations obtain of consist of unanalyzable
“elementary experiences.” However, “analyzing” “unanalyzable wholes” (namely, “elementary
experiences”) appears to be somewhat problematic. As a result, Carnap explains that “quasi-analysis” is
actually “a synthesis which wears the garb of an analysis.” (LAW 121; emphasis added). That is, as just
noted, although the construction/reduction process of translating concepts/objects into other
concepts/objects in the Aufbau is strictly analytic, the method of constructing-from/reducing-to
concepts/objects by way of “quasi-analysis” is synthetic. But what is this “synthesis?” In particular, does it
mean that statements about say, a lower-level concept/object c are not interchangeable with statements
about E and R? No. To see why this is the case, first note the following general explanation Carnap gives
of quasi-analysis: “We overcome the difficulty which results from the fact that elementary experiences are
unanalyzable by introducing a constructional procedure which, even though synthetic, leads from any
basic elements to objects which can serve as formal substitutents for the constituents of the basic
elements.” (LAW 110; emphasis added) That is, quasi-analysis is simply “quasi” because it attributes a
certain formal structure to what is, in principle, unstructured in virtue of being unanalyzable; namely, it
provides a structure that acts a logical, analyzable proxy for elementary experiences, which as such, serves
7
as the analyzable foundation for all fields of knowledge. Carnap makes this clear when he continues in the
immediately following passage: “We call [these objects constructed by quasi-analysis] formal
substitutents, because all assertions which hold for the constitutents hold, in analogous form, also for
them. We call this procedure quasi analysis.” (LAW 110) That is, and crucial to note, a reduction to the
objects created by quasi-analysis, is, analogously, a reduction to the elementary experiences and R, a point
that is behind Carnap’s remark that “the subjective origin of all knowledge claims lies in the contents of
experiences and their connections” (LAW 7; emphasis added). For, Carnap writes on p. 111, “It is of
importance whenever we are concerned with unanalyzable units of any kind, that is, with objects which, in
their immediate given-ness, do not exhibit any constituents or properties or aspects. These objects are
given, as it were, only synthetically; nevertheless, as a result of our procedure, we can ascribe various
characteristics to them” (LAW 111). In short then, for our purposes, this means that according to Carnap,
all knowledge claims are first reducible to the products of quasi analysis (“basic relations” (§§75-83)
which obtain of elementary experiences), and then second, analogously, by way of quasi-analysis, to the
elementary experiences themselves, and R.
So in short, with all additional technical detail set aside, Quine writes in "Russell's Ontological
Development" (1966) that: "[In the Aufbau,] Carnap achieved remarkable feats of construction, starting
with sense data and building explicitly, with full Principia techniques and Principia ingenuity, toward the
external world.” (TT; ROD 84) In still other words, as Quine indicates here and elsewhere, in the Aufbau,
Carnap had taken the Russellian epistemological concerns to subtler, if not more daring heights; according
to Quine, epistemology had, thanks to Carnap, taken a clear and decisive logical turn. And initially, this
seemed to mean a turn for the better.17
§2 Quine’s Reaction to “Radical” Reductionism: A Sensitivity to Circularity
§2.1 “Attenuated” v. “Radical” Reductionism
17 For more instances of Quine’s praise of the Aufbau’s technical achievements, see at least, "Homage to Rudolf Carnap"
(1970) (WOP 40), letter #37, March 6, 1936 Quine to Morris (DCDV 204). Also note Quine's remarks to the same effect in the
Fara video interview.
8
As is well-known, Quine rejects the idea that any sentence claim can, both in principle and in practice, be
confirmed or denied on the basis of just experience; this rejection is behind his attack on the “second”
dogma of empiricism, namely his distaste for allegedly “synthetic” claims. In still other words, Quine’s
renouncement of the synthetic amounts to a repudiation of what he refers to a “subtler and more tenuous
form” (FLPV; TDE 40) of reductionism, or what we can refer to, after Quine, as “attenuated” (FLPV;
TDE 41; emphasis added) reductionism. Meanwhile, it is also well-known that Quine rejects what he
construes as Carnap’s more “radical” (FLPV; TDE 39; emphasis added) form of reductionism, where, as
explained in §1 above, it is alleged that all statements may be reduced, or in other words, translated into
sense data and ordered by at least one fundamental relation (which, as we saw in Carnap’s case, consisted
of, respectively, E and R). Or as Quine puts it: “Radical reductionism, conceived now with statements as
units, set itself the task of specifying a sense-datum language and showing how to translate the rest of
significant discourse, statement by statement, into it. Carnap embarked on this project in the Aufbau”
(FLPV; TDE 39; emphasis added).18
In short then, according to Quine, the distinction between attenuated reductionism v. radical
reductionism is, respectively: [1] The truth value of certain sentences (namely, “synthetic” ones) may be
established solely by appealing to empirical evidence and [2] All knowledge claims may be reduced, or in
other words, translated into empirical experiences, where such empirical experiences are ordered with a
select amount of fundamental relations (e.g. Carnap’s “remembering as similar”).
18 One should note that Quine says “sense-datum language” (emphasis added) here, not “sense-datum” simpliciter. In other
words, contrary to what we just saw in §1, it seems that Quine thought that in the Aufbau, Carnap was attempting to reduce all
knowledge to a primary language about sense data (which we may refer to as L), rather than to the sense data (and R) itself.
And in some respects, Quine is correct, “quasi-analysis,” as we saw above, consists in constructing an analogous formal
language about elementary experiences; particularly, the construction of the “basic relations” that obtain of elementary
experiences. Nevertheless, as we also saw, Carnap clearly thought that “all knowledge lies in the contents of experiences and
their connections” (LAW 7), not just in sentences made about E and R. So we might take Quine’s insistence on referring to a
sense datum language here as an artifact of Quine’s behaviourism, where only sentences may be true or false, not mental
entities (see for instance, WO §30-31, POT 69, FSS 90-92 and OME). Meanwhile, so-called mental entities must be understood
in physical terms (e.g. as nerves firing, etc. See at least RR 34 and OME). In fact, although Quine talks about Carnap reducing
to a sense-datum language here (and elsewhere, e.g. FLPV; TDE 39 and FSS 13), as noted in my introductory remarks, he
claims that he rejects the Aufbau primarily because it invokes a “mentalistic monism” (FSS 15). In other words, Carnap appeals
to elementary experiences and not a.) sentences about elementary experiences and/or b.) elementary experiences construed as
physical states (e.g. nerves firing, etc.) However, regardless if in this respect Quine appears to be intermittently imposing his
own epistemological predilections on the Aufbau, it may be argued that its “radical” reductionism still seemed paradoxical to
Quine, or at the very least, struck him as an impossible task (see above for more detail).
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§2.2 The Paradox of Radical Reductionism
As briefly noted above, it appears that, on the face of it, Quine eschewed the notion of “synthetic”
claims—and so, the theory of “attenuated” reductionism—in light of his holism, where, according to this
theory, no sentence stands or falls on its own, regardless of what the empirical evidence tells us. For
instead, the Quinean story goes, whether or not we reject or accept a given sentence also depends on its
relationship to the rest of the theory at hand; as a result: “statements about the external world face the
tribunal of sense experience not individually, but only as a corporate body.” (FLPV; TDE 41)19
But as noted in my opening remarks to this paper, I think that the reasons behind Quine’s rejection of
attenuated reductionism are a bit more complex than this, although Quine never directly says as much. In
particular, as already suggested above, it may be shown that Quine’s repudiation of “radical” reductionism
ultimately entails his rejection of “attenuated” reductionism by way of a rejection of what I refer to as the
physicalist version of the naturalistic circle.
To see why this appears to have been the case, we must first understand how and why Quine
rejected the paradoxical “radical” reductionism manifest in the Aufbau. To begin, note a particularly
revealing line from Quine’s 1993 paper “In Praise of Observation Sentences:” "The lively objection to
[protocol sentences], as vehicles of evidence for our knowledge of the external world, is that they already
assume such knowledge … But the answer is that they need not.” (IPOS 108; emphasis added). In other
words, here, Quine is defending the idea that his notion of an “observation sentence—” a term that he uses
interchangeably in this paper (IPOS 108) with the term “protocol sentence—” is not, in the course of the
human being’s learning process, initially “theory-laden” (IPOS, 110). Rather, our initial use of language is
purely reflexive; a product of our being habituated to say a given sentence S when we experience a given
range of neural intake M (IPOS, 109). Only later, through a process that is not relevant for us to examine
19 For more on Quine’s notion of holism, see at least: “The Five Milestones of Empiricism” (1975) (TT) “Two Dogmas in
Retrospect” (1991) and POT 13-16. Note that in “The Two Dogmas of Empiricism,” Quine credits Duhem (1906) and
Lowinger (1941) for initially working out the fundamentals of holism. Quine’s notion of “underdetermination” also comes into
play here, but for our purposes, and given length restraints, we need not throw it into the mix. See Bergström (2004) for more
detail.
10
here, do human beings acquire theory, and relatedly, knowledge. But what we must ask is: Why does
Quine balk at the idea that our observation sentences somehow initially “assume” knowledge such that,
say, when we first learn to use the word “Mama” correctly, that we allegedly know who and what Mama
is when we say it?
Two reasons, where the first, and most well-known is: According to Quine, science tells us that our
initial input is remarkable “meager” (FSS, 16), consisting of “the mere impacts of rays and particles on
our surfaces and a few odds and ends such as the strain as walking uphill” (FSS 16). In this respect, our
initial input consists of unrelated bits and pieces of sense data. As a result, we are not in any respect
“aware” of such nerves firing (see at least FSS, 17-18, RR, 2-4). Instead, such input must be understood as
our body’s initial and unconscious state of reacting to the world—not only when we are infants and first
experience the world, but also in terms of our “outermost” interface with the world, as it assails us
throughout our entire lives. Thus, “knowing—“ where, according to Quine, knowing consists of at least
some kind of psychological ability to evaluate data such that we may say the right thing at the right time,
and as a result, at the very least, be “aware” of what is being experienced and what to say20—is simply not
an option at this stage of our data acquisition. Rather, according to Quine, our initial, most outermost
interface with the world occurs at what he characterizes as the the purely “receptual” (FSS 17) level of
data acquisition; accordingly, “awareness,” and so, the possibility of knowledge occurs only at the
“perceptual” (FSS 17) stage of data acquisition.21
Second, although Quine never explicitly says as much, it seems that assuming knowledge in our
initial experience of the world incurs the second horn of Meno’s Paradox, namely, “[A man] would not
seek what he knows, for since he knows it, there is no need of inquiry.” (M 80 d-e). To see why this is the
case, we must briefly re-examine what is going on behind the scenes in Carnap’s Aufbau. In particular,
realize that if any statements about a concept/object a are, in fact “translat[able” (FLPV; TDE; 39) or in
other words, are logically equivalent to some set of elementary experiences E and the relation of R, it
seems that in virtue of just experiencing E and knowing R and the theory of relations, we must
20 This is part and parcel of Quine’s behaviorism; see at least FSS and POT where he gives a general outline of this position.
21 For more on the distinction between “reception” and “perception,” see at least FSS 17-18 and RR 2-4.
11
simultaneously know a and any statements about a as well—at least implicitly—much in the same way
that if we know A  B and we know our equivalence rules, then we know ~A v B. For again, if it is the
case that all concepts/objects may be reduced (namely, are logically equivalent to elementary experiences
and R), then it seems that all our possible knowledge of the external world (including scientific theory)
“lies in” (LAW 7) our “elementary experiences” and R, if only in the respect that “lies in” means logically
equivalent to.22 For as noted above, keep in mind that the Aufbau’s reductionist program was modeled
after the logistic reduction carried out in the Principia (although the latter engaged in a fatally flawed
reduction, as pointed out by Gödel (1931)). In fact, Quine writes in this regard in From Stimulus to
Science:
The conclusion [Whitehead and Russell] drew was that mathematics is translatable into pure logic (FSS
9)…[The] total translatability [of mathematics and their basic laws and interrelations] into just elementary
logic and a single familiar two-place predicate, membership, is of itself a philosophical sensation (FSS 910; emphases added)…Russell adumbrated [the idea of this kind of construction] in Our Knowledge of the
External World, and a dozen years later, Rudolf Carnap was undertaking to carry it out. Carnap’s effort
found expression in Der Logische Aufbau der Welt (1928). (FSS, 10; first two emphases added)
However as far as I can tell, Quine did not overtly reject the Aufbau because, from at least a strictly
logical point of view, it seems that to show that all knowledge that is possibly derivative of a given
elementary experience E, the relation R and the theory of relations, is as such, “assumed” in these primary
elements, through, quite simply, the “total [logical] translatability” (FSS 10) of knowledge into these
primary elements. Rather, as noted in my introductory remarks, he accuses Carnap of embracing a
“mentalistic monism” in the Aufbau because, Quine asserts, according to Carnap, “elementary
22 With all the technical subtleties of the synthesis that occurs with quasi-analysis aside. For as noted earlier, the point we must
grasp is Carnap’s claim that all knowledge may, in principle, be reduced, or in other words, translated via logical equivalence
(as manifest by theory of relations) to elementary experiences and R, regardless if the last step in this reduction (quasi-analysis)
incurs a method of establishing “synthetic” equivalence. More importantly still, this is how Quine understood the Aufbau.
Recall, for instance the following passage from “The Two Dogmas of Empiricism” where he writes: “Radical reductionism,
conceived now with statements as units, set itself the task of specifying a sense-datum language and showing how to translate
the rest of significant discourse, statement by statement, into it. Carnap embarked on this project in the Aufbau” (FLPV; TDE
39; emphasis added). See also the passages cited above from From Stimulus to Science and “Epistemology Naturalized,” where
Quine makes similar claims. However, as noted in footnote 18, it must be pointed out that at least at some level, Quine indicates
that Carnap was not translating all knowledge into E and R, but instead, into certain statements about E and R, where, it would
12
experiences” were psychological “global units” (FSS 10) that as such, consisted of “the individual’s total
experience at that moment” (FSS 10).23 As a result, Quine explains, these psychologically experienced
wholes were, according to gestalt psychologists—as well as according to Carnap and a number of his
philosophically-inclined contemporaries—24 units that one is necessarily “aware of” (RR 1-4) when they
are being experienced. And in the respect that one would be “aware” of such units, one would, to at least
some inchoate degree, know them. In short then, as Quine sees it, according to this psycho-epistemological
account of the world, “awareness of” was roughly equivalent to “knowledge of”—such “wholes” were
alleged to be the psychological foundations of knowledge (RR 1-4).25
With this in mind, realize that on the face of it, although it does not appear that Quine calls the Aufbau
a “sort of fiction” (IPOS, 116) and “make believe” (OR; EN 75) because it invokes the second horn of
Meno’s Paradox, for all intents and purposes, this must be understood as his deeper objection; overt or
not: Carnap’s “mentalism,” or what Quine also refers to as his “phenomenomalism” (FSS 15-16) is not
just unconvincing because it incurs vague and suspicious mental entities (namely, “elementary
experiences”), but worse still, as just noted, these entities allegedly admit of immediate awareness, and
thus, knowledge of the world. And not just rudimentary knowledge, but, it seems, knowledge that is
logically equivalent to all the theories and knowledge claims possibly derivative of a given elementary
experience or experiences. Note in fact, where Quine does somewhat obliquely admit as much in
“Epistemology Naturalized” (1968), paying particular attention to the idea that it would be nice, Quine
seem, these statements constituted what we referred to earlier as some primary language L. Either option however, as we see
above, would have been problematic for Quine.
23 Moreover, Quine thought that despite all the logically machinery that Carnap appealed to in the Aufbau, he could not
adequately account for our ability to make spatial identifications. For more on this, see at least FLPV; TDE 40 and OR; NK 7677.
24 Recall Footnote 14 of this paper.
25 Or as Quine puts it: “What are given in sensation are smells, noises, feels, flashes, patches of color and the like…But in the
present century the Gestalt psychologists reacted against these conditions. Experiment suggests, and introspection as well, that
what are sensed are not primarily those sensory elements, but significantly structured wholes (RR 1)… The building blocks
[needed to construct our knowledge of the external world] had to be irreducibly mental and present to consciousness [namely,
one had to be “aware” of them]. Given these ground rules, the Gestaltists win hands down” (RR 2)
13
thinks, if we could show that all of science is translatable to “logic, observation terms and set theory”
(OR; EN, 76), and as such, “[show] that everything done with the one apparatus could in principle be done
with other” (OR; EN, 76). But quite, frankly, he tells us, this is impossible. In other words, Quine did
indeed think that the Aufbauian project was paradoxical, although not quite in Meno’s respect that we
would be unmotivated to learn what we already know, but in the respect that it is simply not possible that
in virtue of just “elementary experiences” and R we simultaneously know all of what we eventually come
to learn, particularly, scientific theory, or as Quine puts it: “certainly we did not grow up learning
definitions of a physicalist language in terms of a prior language of set theory, logic and observation”
(OR; EN, 76; emphasis added).26 In fact, Quine had already put his finger on what seems to be the sheer
impossibility of assuming such a cache of sophisticated logical ability some eighteen years earlier when he
wrote in “The Two Dogmas of Empiricism:”
The language which Carnap adopted as his starting point [in the Aufbau] was not a sense-datum language
in the narrowest conceivable sense, for included also the notations of logic, up through higher set theory.
In effect it included the whole of language of pure mathematics. The ontology implicit in it (that is, the
range of values of its variables) embraced not only sensing events but classes, classes of classes, and so
on. Empiricists there are who would boggle at such prodigality. (FLPV; TDE 39; emphasis added)
Who, then, was “boggling?” We might, given what we have seen above, conclude that it was Quine who
found himself gasping at such epistemological “prodigality.” In fact, in so many words, Quine repeats this
point in his last book, From Stimulus to Science, when he writes: “we are given a canon or procedure [in
the Aufbau], and a brilliant one, but not one that makes the theory of the external world translatable into
the language of sense experience. That is too much to ask.” (FSS 13; emphasis added)
26
Note the entire passage where Quine says as much: "We should like to be able to translate science into logic and observation
terms and set theory. This would be a great epistemological achievement, for it would show all the rest of the concepts of
science to be theoretically superfluous. It would legitimize them—to whatever degree the concepts of set theory, logic, and
observation are themselves legitimate—by showing that everything done with the one apparatus could in principle be done with
the other. If psychology itself could deliver a truly translational reduction of this kind, we should welcome it; but certainly it
cannot, for certainly we did not grow up learning definitions of physicalist language in term of a prior language of set theory,
logic and observation." (OR; EN 76)
14
So in short, according to Quine, the “radically” reductionist program that Carnap set up for himself
in the Aufbau, however technically deft, was not only plagued with mentalistic preconceptions—namely,
“awareness” at the initial stages of knowledge acquisition—it was a hopelessly impossible project—we
are not, thanks to just “set theory, logic and observation” (OR; EN 76) initially privy to our knowledge of
the external world. So, to be perfectly clear, in this respect, Quine’s rejection of the “radical”
epistemological reductionism invoked in the Aufbau should be understood in the context of an implicit
reaction to a variant of Meno’s Paradox,27 particularly, the idea that to know what we do (particularly,
scientific theory), we must somehow, already know it, or at the very least, it must be immediately
accessible to us by way of an “awareness” of our “elementary experiences, ” R, and our grasp of logic.28
§3 The Naturalistic Circle
With Quine’s rejection of “radical” reductionism in mind, where, as just shown, this rejection seems to
turn on a somewhat implicit rejection of a form of Meno’s Paradox, we must now take the two versions of
what I characterize as the “naturalistic circle” into account. For as noted in the introduction of this paper. I
argue that Quine’s rejection of what we may, after Quine, characterize as Carnap’s “phenomenalistic”
27 Although I disagree with some of Fogelin’s (2004)
interpretations of “Epistemology Naturalized,” (particularly, the
passages that I cite above), we do seem to be in implicit agreement when he writes: “as long as the doctrinal [i.e. the Carnapian]
demand [for reductionism] is in place, we are cut off, at the pain of begging the question, from exploiting a realm of highl y
reliable knowledge, namely a knowledge drawn from the empirical sciences.” (27) In other words, Fogelin is pointing out
Quine’s uneasiness with the circularity involved in radical Aufbauian reductionism, a circularity that I characterize here in
terms of a broader historical context, namely, Meno’s Paradox.
28 I am grateful to recent comments by David Martens, who has helped to clarify the basic structure of the argument that I am
attributing to Quine here. I have slightly modified his characterization to read as follows:
P1. If the Aufbau’s reductionism is correct, then, for every knowledge claim K, K is logically equivalent to some set of
elementary experiences E and R (or as Quine seems to insist (recall footnote 18 of this paper), some primary language L about
E and R).
P2. If, for every knowledge claim K, K is logically equivalent to some set of elementary experiences E and R, then all our
possible knowledge is logically contained in our elementary experiences and R (or alternatively, L)
P3. If all our possible knowledge is logically contained in E and R (or alternatively, L), then all our knowledge is immediately
accessible to us, not only as children, but in terms of any elementary experiences related by R (or alternatively, L) that we
might have.
P4. Children (and adults) do not already know everything that they eventually come to learn (e.g. scientific theory) either in
terms of E and R or L.
15
radical reductionism—in light of its paradoxical nature—could only have reinforced his faith in
naturalism. In turn, Quine rejects what we may characterize as—after Quine—“physicalistic” radical
reductionism and as such, breaks what I call the physicalist version of the naturalistic circle, which, it may
be shown, entails his rejection of “attenuated” reductionism. Concomitttanly, because “the two dogmas
are indeed, at root identical” (FLPV; TDE 41), a rejection of the “synthetic” amounted to a rejection of the
“analytic” and thus, the need for “certainty” altogether. As a result, as I see it, Quine could simply dismiss
the Humean version of the naturalistic circle while the scientific method, despite its fallibility, could be
embraced.
§3.1 The Naturalistic Circle: Hume’s Version
According to at least Hume, the scientific method—29 where that method consists of, simply put,
gathering our information about the world by means of our senses and/or various hypotheses compiled
from the information given to us by the senses—is a fallible method in the respect that its subject matter
consists of “matters of facts.” (T 1.3) This is the case because according to Hume, knowledge claims that
are based on matters of fact are based on the relation of cause and effect. (T 1.3) However, no causal
relation is, according to Hume, necessary, but instead, is a product of imagining certain constantly
conjoined events as apprehended through any and/or all of our five senses, and as such, any causal relation
can always be imagined otherwise without creating a contradiction. As a result, no matter of fact is
necessarily true. Accordingly, because the scientific method is constructed from consideration of matters
of fact, no result it yields is necessarily true (see T 1.3). Consequently, by appealing to the scientific
method to show that we must use the scientific method to philosophically examine the world, where a
C. So, the Aufbau’s reductionism is not correct.
29 Hume identified this as the method of “experience.” See for instance, the Introduction to the Treatise (Intro. 7; SBN xvixvii), where Hume writes: “And as the science of man is the only sound foundation for the other sciences, so the only solid
foundation we can give to this science must be laid on experience and observation.”
16
component of that world is the scientific method itself, one makes a claim that is not necessarily true; no
claim derivative of the scientific method is necessarily true, even if it’s the claim: “We must use science to
examine science.” As a result, it is simply not certain that we should be doing naturalized philosophy at
all; this is what we may identify as Hume’s version of the “naturalistic circle;” a circle that Hume
intermittently torments himself with, particularly in the Treatise.30
It is no surprise then, that Quine, latter-day Humean empiricist that he was, puts his finger on this
circle approximately two hundred years later in Roots of Reference, although here, Quine locates the circle
in a historical venue that preceded Hume by thousands of years:
Ancient skepticism, in its more primitive way, likewise challenged science from within. The skeptics
cited familiar illusion to show the fallibility of the senses; but this concept of illusion rested on natural
science, since the quality of illusion consisted simply in deviation from external scientific reality (RR, 2-3)
In other words, Quine’s point is: Ancient skepticism challenged science from a “scientific point of view”
because the concept of an illusion is itself a scientific concept; an “illusion” is, by definition, a “deviation”
from an empirically confirmable fact. As a result, the idea that the senses are fallible—and thus
susceptible to illusion—is itself a claim that is derived from the senses, which means that the claim “The
senses are fallible” seems to be fallible itself, and thus, just as susceptible to illusion. As such, just as
Hume would complain thousands of years later, it seems that science may be “challenged … from within”
(RR, 2).31
30 See especially, 1.4.7, particularly where he writes: “This intense view of these manifold contradictions and imperfections in
human reason has so wrought upon me, and heated my brain that I am ready to reject all belief and reasoning, and can look
upon no opinion even as more probable or likely than another. Where am I, or what? From what causes to I derive my
existence, and to what condition shall I return? Whose favor shall I count, and whose anger must I dread? What beings surround
me? And who have I any influence, or who have influence on me? I am confounded with all these questions, and begin to fancy
myself in the most deplorable condition imaginable, inviron’d with the deepest darkness, and utterly depriv’d of the use of
every member and faculty.” (T 1.4.7.7-8; SBN 268-9) Also see Husserl (C 89-90) for his characterization of Hume’s
naturalistic predicament.
31 Also see “Epistemology Naturalized” (OR), where Quine specifically mentions the “Humean predicament” (72) in regard to
Hume’s naturalistic method. However, in the course of doing so, depending on how we read this passage, Quine seems to
infuse his own physicalist version of the naturalistic circle in Hume, rather than realizing that Hume’s position was more a
manifestation of the ancient predicament (as characterized by Quine in RR, noted above). Note: “What then of the doctrinal
side [of the epistemology of natural knowledge], the justification of our knowledge of truths about nature? Here, Hume
17
How then, can an empiricist, a naturalistic philosopher, avoid this? For instance, should one, like
Husserl—in partial response to Hume’s version of the naturalistic circle32—appeal to a “first science,” or
in other words, to what Husserl called the “epoché?” For on this account, one might, it seems, properly
justify his or her decision to use science to talk about the world. For in the case of Husserlian
phenomenology, the decision to use science would not be a product of the insights gained from empirical
(and thus fallible) experience, but instead, would be a product of insights gained from the epoché, or the
“first science,” which, according to Husserlian phenomenologists, yields necessary truths (see at least I 1,
lines 59-60). However, as is well-known, Quine was loath to appeal to anything like a “first science,” that
as such, is alleged to stand on a foundation built from anything other than empirical observation.33
§ 3.2 The Naturalistic Circle; The Physicalist Version
With the general structure of the Humean version of the naturalistic circle in mind, let’s now take a look at
what I characterize as the physicalist version, which was brought squarely into focus by Quine. As noted
earlier, according to him, sense data, which he prefers to construe as “neural input,” is fragmented, which
as such—at least at the level that Quine identifies as reception—consists of experiences that we are in no
way “aware” of and so, as explained above, could not possibly admit of knowledge, even knowledge in
despaired. By his identification of bodies with impressions he did succeed in construing some singular statements about bodies
as indubitable truths, yes; as truths about impressions, directly known. But general statements, also singular statements, about
the future gained no increment of certainty by being construed about impressions.” (OR; EN 71-72) In other words, as Quine
sees it here, Hume “despaired” because in virtue of identifying predictive statements (both general and singular) with statements
about fragmented impressions, the former, predictive statements were to be understood as uncertain, evidently because
statements about impressions do not admit of certainty. In this respect, Quine would be correct; Hume does torment himself
over the fact that because the relation of cause and effect is rooted in experience (impressions), it is uncertain, and thus, all
predictive claims are uncertain. However, when this passage from “Epistemology Naturalized” is read another way, it seems
that Quine is implying that Hume may have even identified predictive statements with impressions, just as Quine seems to think
that Hume identified bodies with impressions (Quine may also be read as implying as much in RR 1-3). However, at no time in
the course of Hume’s work does Hume explicitly identify, or in other words, reduce and/or translate statements into
impressions where in turn, he “despairs” about the uncertainty of the latter becoming a property of the former in virtue of such
an identification. As a result, if this is, in fact Quine’s intention here, we may conclude that he is simply imposing the
physicalist version of the naturalistic circle on Hume. Regardless, as noted above, Quine clearly recognized what I characterize
as the “Humean” version of the naturalistic circle, although he captures it terms of ancient skepticism. Moreover, thanks to
Pakaluk’s (1989) citations from Quine’s 1946 lecture notes on Hume, we see Quine specifically refer to Hume in regard to what
I characterize as the Humean version of the naturalistic circle. See for instance, pp. 455, 457 (#490), 459 (#500).
32 See Rocknak (2001) for more detail on Husserl’s reaction to Hume’s version of the naturalistic circle.
33 See at least POT 16-21.
18
Quine’s behavioristic sense of the word.34 Rather, as also explained earlier, according to Quine,
“awareness” and so, any possibility for knowledge, only emerges at the level of perceptual similarity. In
this general respect, Quine’s epistemology is fearlessly “physicalistic—“ it paints a picture where the
primary source of all our knowledge consists of nerves firing, where “awareness” of such events is
decisively absent. Recall that this way of looking at data acquisition is opposed to Carnap’s
“phenomenalism,” where, as noted, the source of all our knowledge consists of mentalistic entities that are
related (at least by R) and we are aware of.35
But as noted in my introductory remarks, adopting the physicalist stance appears to incur another
version of the naturalistic circle, which unfolds, quite simply, as follows: If one assumes physicalism and
attempts to reduce, or in other words, claims to translate knowledge, particularly, knowledge of scientific
theory, to nerve inputs, where such input does not admit of knowledge, then it seems that such knowledge
is effectively equated to something that is not knowledge, namely: “smells, noises, feels, flashes, patches
of color and the like” (RR 1). As a result, it simply follows that if we translate science, say, the scientific
claim X “All our scientific theory may be reduced to physical input” to physical input, then all of science,
e.g. in this particular case, X, is equivalent to nonsense; that is, mere “impacts on our sensory surfaces”
(POT 1). This then, is the physicalist version of the naturalistic circle, which Quine discusses tirelessly
throughout the body of his work.36
§4 A Summary of What is at Stake
34 Note at least one passage where Quine makes this distinction between reception (non-awareness) and perception (awareness)
clear: “We have undercut the Gestalt psychologist’s criticism of sensory atomism by dropping the awareness requirement and
talking directly of physical input as at the sense receptors. This however, is only half the story. Awareness and Gestalt still
claim an important piece. Sensory receptors operate at the level of reception, and Gestalt operates at the level of perception”
(RR 4; emphases added)
35 Or in Quine’s words: “Though Carnap had represented the phenomenalistic orientation of his ‘rational reconstruction’ as a
pragmatic choice without metaphysical significance, Neurath probably saw it (and I do) as embracing a Cartesian dualism of
mind and body, if not mentalistic monism. Physicalism, on the other hand, is materialism, bluntly monisitic except for the
abstract objects of mathematics.” (FSS, 15)
36 See for instance, RR 2-4, OR; EN 71-72, 74-75, 83-84, TT; EC 24, POT 1-20 and WO 2, 4. For an appetizer, note just one
of these passages: “Science itself teaches that there is no clairvoyance; that the only information that can reach our sensory
surfaces from external objects must be limited to two-dimensional optical projections and various impacts of airwaves on the
eardrums and some gaseous reactions in the nasal passages and a few kindred odds and ends. How, the challenge proceeds,
could one hope to find out about that external world from such meager traces? In short, if our science were true, how could we
know it?” (RR 2; emphasis added)
19
To best organize the three main concerns that we have been dealing with, namely, Meno’s Paradox as it is
manifest in the “radical” reductionism of the Aufbau, Hume’s version of the naturalistic circle and the
physicalist version of the naturalistic circle (setting aside any discussion of “attenuated” reductionism for
the moment), realize that Quine was faced with the following epistemological mess: If we “radically”
reduce or translate knowledge to sense data then it seems that:
a.) We must assume such knowledge in the sense data by way of the Gestalt psychologists’ “wholes,” or
what Carnap preferred to call “elementary experiences;” this constitutes what we might call, after Quine,
“phenomenalistic” radical reductionism. Yet as noted, according to Quine, with all suspect mentalistic
overtures aside, doing as much is simply impossible. In other words, the Aufbauian project reminds us of
the second horn of Meno’s Paradox, namely, the idea that we would not seek knowledge if we already
knew such knowledge, where in this case, Quine translates the problem of a lack of motivation to seek
what we already know into bleak impossibility: it’s just not the case that in virtue of our “elementary
experiences” and knowledge of R and all of set theory that we know all possible knowledge claims
logically derivative of E and R; this would simply “be too much to ask” (FSS 13)
b.) Regardless if we assume that knowledge is or is not present in the sense data (e.g. in terms of
“elementary experiences”), empiricists widely accept the fact that empirical, and thus scientific claims, are
fallible—as was made particularly clear in Hume’s philosophy. Thus, if the claim “We must use science to
examine science” is a scientific claim, then it is a fallible claim; this is Hume’s version of the naturalistic
circle, and as such, “challeng[es] science from within.” (RR 2)
c.) Moreover, if—unlike the Aufbau Carnap—we conclude that our sense input does not admit of
knowledge, it seems that if we reduce, or in other words, translate scientific theory and/or knowledge into
sense data conceived of from a physicalistic point of view (and thus, engage in what we might call, after
Quine, “physicalistic” radical reductionism), then knowledge, particularly knowledge of scientific theory,
equates to nerves firing, and thus, it seems, to nonsense. This is the physicalist version of the naturalistic
circle.
§5 The Solution: Naturalism Embraced; “Radical” and “Attenuated” Reductionism Rejected
20
Quine’s three-fold solution to this mess is, as I see it, quite simple although many aspects of it have been
much contested.37
[1] We cannot, according to Quine, assume knowledge in our initial input; in other words, Quine must
flat-out reject Carnap’s “phenomenalistic” radical reductionism as it is manifest in the Aufbau. For as
noted above, if we did not, one simply assumes too much, causing us in fact, to “boggle at [the]
prodigality” (FLPV; TDE 39) inherent in such an endeavor. Or in still other words, this means that Quine
was aware—however implicitly—that Carnap’s Aufbau invoked a paradox, reminiscent of the idea that
one “would not seek what he knows, for since he knows, there is no need of inquiry” (M 80 d-e).
Meanwhile, as Quine sees it, contemporary scientific research shows that our initial input (“reception”)
does not admit of knowledge; namely, science seems to favor the physicalistic approach. In other words,
ironically enough,38 it seems clear enough that a simple Platonic Paradox appears to have justified Quine’s
endorsement of contemporary scientific research, but quite independently of Quine’s pragmatic reasons
for embracing naturalism. Put still another way, the paradox of “radical” reductionsim may have made it
quite clear to Quine that it is just unreasonable to assume knowledge in our initial interface with the
world; or in still other words, it is simply unreasonable to take what Quine characterizes as a
“phenomenalistic” approach. So instead, we must adopt what contemporary science seems to favor,
namely, the “receptive” model of data acquisition. As a result, problem a.) noted above is avoided; our
initial input is not only bereft of knowledge (even as adults), we are, according to contemporary scientific
research, born knowing virtually nothing.39
37 We simply do not have time to take any of these critiques into account here; see at least: Perspectives on Quine (1990), and
The Philosophy of W.V. Quine, 1986 and 1998.
38 In the respect that Plato was, by no stretch of the imagination, a naturalistic philosopher. For according to Plato, the way to
the truth was by way of “pure” rationality, whereas empirical evidence only created confusion, if not knee-jerk relativism (see
at least, the Theaetetus).
39 Although we do have some rudimentary ability to relate at the perceptual level. For more on this, see at least FSS. However,
on the face of it, this solution seems to incur the first horn of Meno’s Paradox, namely: How could we learn, look for, or
acquire knowledge, if we do not already have such knowledge? As such, it seems that Quine’s solution to the problems
21
[2] However, as noted above, if one translates knowledge claims into what science tells us constitutes our
outermost interface with the world (namely, fragmented sense data (“reception”)) one effectively
translates knowledge into nonsense; recall that this is the physicalized version of the naturalistic circle
explained above. To specifically avoid this predicament, Quine must claim that at best, knowledge claims
are “evidence[d]” (See at least TT; EC, 24; emphasis added) by stimulus, where, crucial to note, the
notion “evidenced by” is not, equivalent to “equivalent to.” In other words, by "evidence," Quine is
referring to the significant but not comprehensive influence that sense data has on a sentence. So instead,
according to Quine, and as noted above, to grasp the given sentence’s entire meaning, and likewise its
truth value, and thus to properly know it, it must be understood in terms of the larger context of the theory
it is embedded in. As a result, and crucial to note, this means that a rejection of “radical” reductionism (in
terms of both a phenomenalistic and physicalistic approach) entails a rejection of “attenuated”
reductionism. For if a knowledge claim is not reducible to, and thus, is not equivalent to sense data, but
instead, its meaning, and likewise, its truth value can only be obtained upon considering it in terms of the
theory it is embedded in, 40 it simply follows that there are no knowledge claims whose truth values may
be obtained solely in virtue of empirical confirmation or disconfirmation. In short then, problem c.) noted
above is avoided; knowledge, knowledge of scientific theory in particular, is simply not equivalent to
nonsense. And as an added bonus, the “synthetic” dogma (namely, “attenuated” reductionism) is revealed
for what it is—a dogma.
[3] With the rejection of “attenuated” reductionism—which, as we just saw, is entailed by Quine’s
rejection of physicalistic “radical” reductionism—the expectation for “certainty” is concomitantly
mentioned above could invoke a critique of certain forms of behaviorism. But it is not relevant to discuss these implications
here.
40 For a bit more detail on Quine’s holism, see at least “Two Dogmas in Retrospect,” particularly 268, where he discusses the
distinction between “radical” v. “moderate” holism (note however, that this distinction does not affect our present discussion).
22
dropped, for “the two dogmas are, indeed, at root identical” (FLPV; TDE 41).41 In other words, according
to Quine, just as no claim may be proven true or false purely in virtue of sense data, no claim may be
proven true or false purely in virtue of its meaning, where the latter (“analytic”) claims, it is alleged, admit
of “certainty” and the former (“synthetic”) claims do not. Rather, no claim, according to Quine, is
“certain,” or in other words, “necessary” (see also, for instance, WOP; NT).42 As a result, and crucial to
note, it simply does not matter if the scientific method, or our choice to employ it, is fallible. What does
matter, according to Quine is that science works, “[the scientific, empirical method] is the best [method]
we know” (WO 4); as such, it allows us to make certain predictions about the world, which include
predictions and hypotheses about scientific theory. According to this line of thought then, we might say
that allegedly certain Husserlian “first sciences” do not allow us to fly to the moon or cure cancer, but
regular old “fallible” science surely does; in this respect, science “matters.” And so, problem b.) noted
above is avoided; the Humean version of the naturalistic circle is simply irrelevant; it is a manifestation of
misplaced expecations.
So in conclusion, when faced with the question of: Where does our knowledge of the external
world come from—a question that Socrates wrestled with thousands of years before Russell, Carnap and
Quine did—Quine was forced to turn to science; in fact, it is no wonder that Quine’s very last book, From
Stimulus to Science, was devoted to “physicalizing” the Aufbau. For, the story goes, when we see that
reducing knowledge to knowledge (e.g. “elementary experiences” R and all of set theory) is absurd
(namely, when we see that phenomenalistic radical reductionism is absurd), we must turn to the more
41 Recall the larger context that Quine made this point in: “The dogma of reductionism, even in its attenuated form, is
intimately connected with the other dogma—that there is a cleavage between the analytic and synthetic. We have found
ourselves led, indeed from the latter problem to the former thought the verification theory of meaning. More directly, the one
dogma clearly supports the other in this way: as long as it is taken to be significant in general to speak of the conformation and
infirmation of a statement, it seems significant to speak also of a limiting kind of statement which is vacuously confirmed, ipso
facto, come what may; and such a statement is analytic.” (FLPV; TDE 41)
42 Although some truths, such as logical truths, are more central, or in other words, significant than others. But we need not
discuss this matter in any more detail here.
23
reasonable scientific account of knowledge acquisition, namely, the idea that we are born knowing
virtually nothing. Yet this does not mean that we should equate such an initial lack of knowledge (nerves
firing, etc.) with what we do know; that is, we should not engage in physicalistic radical reductionism
either, and as such, the physicalized version of the naturalistic circle is avoided. Rather, we must realize
that although all our knowledge claims are supported by empirical evidence, they may not be translated
into them, solving the problem of “if our science were true, how could we know it?” (RR 2).
Concomitantly, this means that no knowledge claim may be proven true or false purely in virtue of
empirical evidence, namely, the synthetic dogma is revealed as a dogma; that is, “attenuated”
reductionism may be rejected. Simultaneously—because the two dogmas are, at root, identical—this also
means that no knowledge claim admits of absolute certainty; inspiring us to lower our somewhat childish
philosophical expectations for science. As a result, we may simply sidestep Hume’s torment (namely,
Hume’s version of the naturalistic circle), and instead, exercise science for all that it’s worth.
24
List of Abbreviations
Books
Carnap
The Logische Aufbau der Welt (LAW)
Hume
The Treatise of Human Nature (T)
Husserl
The Crisis of European Sciences and Transcendental Phenomenology. An Introduction to
Phenomenology. (C)
Ideas Pertaining to a Pure Phenomenology and a Phenomenological Philosophy (I)
Plato
The Meno (M),
Quine
Dear Carnap, Dear Van: The Quine-Carnap Correspondence (DCDV), From a Logical Point of View
(FLPV), From Stimulus to Science (FSS), Pursuit of Truth (POT), Quiddities (Q), Semantics and the
Philosophy of Language (SPL), Theories and Things (TT), Ways of Paradox (WOP),
Papers
Quine
“Epistemology Naturalized” (OR; EN), “In Praise of Observations Sentences” (IPOS), “The Two Dogmas
of Empiricism” (FLPV; TDE), “Two Dogmas in Retrospect” (TDR) “Necessary Truths” (WOP; NT) “On
Mental Entities” (OME)
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