Comments on Brandon Watson’s “The Universe of the Imagination: Malebranche’s
Walking-Soul Argument and Treatise 1.2.6”
It is generally acknowledged that Hume’s philosophical debt to Malebranche is
enormous. On 26th August 1737, shortly after leaving La Flèche where he wrote most of
his Treatise of Human Nature, Hume wrote a letter to a friend in Britain suggesting four
works which would be of help in understanding the metaphysical parts of his reasoning,
the first of which being Malebranche’s The Search After Truth.1 While the influence of
Malebranche on Hume has been duly recognized in the areas of causation, selfknowledge, and natural belief, Watson argues in his interesting paper that there is a
further link between these two philosophers in the area of external existence which has up
until now gone unrecognized in Hume scholarship (p. 1). I will first briefly summarize
Watson’s argument, and then offer two comments.
In the second part of the third book of the Search After Truth, devoted to the
nature of ideas, Malebranche argued for his famous doctrine of the vision in God. More
precisely, the thesis is that we see external objects by means of ideas in God. The
argument for this thesis begins with the claim that it is universally agreed upon that we do
not directly perceive external objects themselves, since we see the sun and the stars and it
can hardly be the case that “the soul should leave the body to stroll about the heavens” to
see the objects present there (Search 217). What we perceive instead are ideas. The minds
immediate object thus when it sees the sun is not the sun, but an idea of the sun. Watson
first points out that a passage in Hume’s account of external existence at Treatise 1.2.6
sounds very much like Malebranche’s own claim that it is only through the presence of
The other works that Hume mentions in the letter to his friend included Berkeley’s Principles of Human
Knowledge, the more metaphysical articles of Bayle’s Dictionary (such as those on Zeno and Spinoza), and
finally Descartes’s Meditations on First Philosophy.
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ideas that we can perceive material bodies (page 8). Here Hume presents a universal
principle that, “nothing is ever really present with the mind but its perceptions or
impressions and ideas, and that external objects become known to us only by those
perceptions they occasion” (THN 1.2.6.7; SBN 67). Since the mind has nothing but
perceptions in front of it, even when we focus our attention “to the heavens, or to the
utmost limits of the universe; we never really advance a step beyond ourselves, nor can
conceive any kind of existence, but those perceptions” (THN 1.2.6.8; SBN 67). Watson
further claims that recognizing Malebranche’s influence on Hume “sheds interesting light
on the passage in question” (page 10). The passage in question presents a “short elegant
argument that indicates the impossibility of our having any ideas of external existence not
of the same kind as our perceptions” (page 11). Hume can be seen as pointing out the
consequences of the walking-soul argument by turning Malebranche’s argument against
all views that place a “veil of ideas” between our minds and external objects, including
Malebranche’s own favored theory of intelligible extension (page 11)!
Watson presents an admirably clear and convincing case for seeing a connection
between Malebranche and Hume on external existence, and a plausible interpretation of
Treatise 1.2.6 in which Hume cleverly turns the tables on Malebranche’s own positive
account of external objects. In response, I will confine myself to two comments.
The first comment concerns Watson’s claim that Malebranche’s influence on
Hume in the area of external existence at Treatise 1.2.6 has, to his knowledge, gone
unnoticed in scholarship. To my knowledge, also, this is an original point about this
particular passage in the Treatise, although there is one secondary source I would
recommend. John P. Wright in The Skeptical Realism of David Hume considers the
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background to Hume’s account of our idea of external existence in physiological theories
of perception, deriving in large part from Malebranche, and argues in favor of a “close
connection” between Hume and Malebranche on the existence of the external world.2
Both philosophers, he argues, make a clear distinction between internal perceptions and
independent external objects, and stress that we are only directly aware of our own
perceptions.3 Wright’s evidence for this connection is not drawn from Treatise 1.2.6,
however, but rather from ‘Of scepticism with regard to the senses’ at Treatise 1.4.2. He
points to Hume’s denial that our own bodies are perceived in space on the grounds that
when we perceive our bodies, we perceive only “certain impressions, which enter by the
senses,” and claims that “Hume’s doctrine that we do not directly perceive the parts of
our own bodies seems to be taken over” from Malebranche’s Search After Truth.4 Wright
also draws attention to the role that natural belief plays in their respective accounts of
external existence. He argues that both philosophers believe that we have a strong natural
propensity to believe that a world of external objects exists, and that this propensity, by
its very existence, gives some justification for the belief that these objects exist.5
The second comment concerns the universal principle. The universal principle
appears three times in Book 1 of the Treatise (in 1.2.6.7 ‘Of the idea of existence, and of
external existence,’ in ‘Of skepticism with regard to the senses’ at 1.4.2.21, and in ‘Of the
immateriality of the soul’ at 1.4.5.15). The principle also turns up again in Book 2 in his
theory of the passions (in ‘Experiments to confirm this system’ at 2.2.2.22), and in his
moral theory in Book 3 (in ‘Moral distinctions not deriv’d from reason’ at 3.1.1.2). The
2
The Sceptical Realism of David Hume, Minneapolis: University of Minnesota Press, 1983, see chapter 2,
especially p. 42.
3
The Sceptical Realism of David Hume, p. 42; see also p. 87.
4
The Sceptical Realism of David Hume, p. 42
5
The Sceptical Realism of David Hume, pp. 74-5.
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principle also appears in the final section on skepticism in An Enquiry Concerning
Human Understanding (Enquiry 12.9-16; SBN 152-5). Given that the principle plays
such an important part in his system, examining those philosophers who might have
influenced Hume on this point is no small matter. Now Watson is certainly not
committed to the claim that Malebranche is the only possible influence here (pp. 9 and
11n.8), however, in order to arrive at a sound judgment about the extent of
Malebranche’s influence on Hume in this passage, it would be worthwhile to consider
some of the other philosophers that Hume might have had in mind.
There is for example good evidence to suggest that Arnauld and Nicole’s The Art
of Thinking also influenced Hume when he wrote the Treatise; indeed, he mentions this
work as one of “the common systems of logic” alongside Malebranche’s Search After
Truth and Locke’s Essay Concerning Human Understanding in the Abstract to the
Treatise.6 Some philosophers have even compared Book 1 of Hume’s Treatise with The
Art of Thinking.7 The important point is that Arnauld and Nicole begin their discussion of
the nature and origin of ideas with a claim similar to the upshot of the walking-soul
argument, that “we can have no knowledge of what is outside us except by means of the
ideas in us.”8 Then there is Locke to consider. Watson acknowledges in a footnote that
Locke offers something like the walking-soul argument in the second book of the Essay
on the origin of ideas (II.1.24), although he argues that the parallel is not as close (page
11n.8). There are certainly other passages in Locke’ Essay however that are very
See the fourth paragraph of the Abstract to the Treatise. For an excellent account of Hume’s acquaintance
with The Art of Thinking and other logic texts, see Charles Echelbarger’s “Hume and the Logicians,” in
Logic and the Workings of the Mind: The Logic of Ideas and Faculty Psychology in Early Modern
Philosophy, volume 5, edited by P. Easton, Ridgeview Publishing Company: Atascadero California, 1997.
7
See Hendel’s introductory essay in Arnauld and Nicole, The Art of Thinking, translated by J. Dickoff and
P. James, Indianapolis: Bobbs-Merrill, 1964.
8
Antoine Arnauld and Pierre Nicole, Logic or The Art of Thinking (1662), translated by J. V. Buroker,
Cambridge: Cambridge University Press, 1996, p. 25.
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suggestive of the same point as the walking-soul argument. In the famous discussion of
primary and secondary qualities, he defines an idea as the “immediate object of
perception” (Essay 2.8.8). He goes on to say at the very beginning of the fourth book on
human knowledge that, “Since the Mind … hath no other immediate Object but its own
Ideas, which it alone does or can contemplate, it is evident, that our Knowledge is only
conversant about them” (Essay 4.1.1). It stands to reason that Locke’s focus when
explaining our knowledge of the existence of external objects is our ideas, as it is the
“actual receiving of Ideas from without that gives us notice” of the existence of external
things (Essay 4.11.2).
It is not part of Watson’s argument that Hume only has Malebranche in mind at
Treatise 1.2.6, but there is no doubt that exploring some of the other philosophers who
also embraced the universal principle will assist in determining the exact nature of
Malebranche’s influence on Hume. The next step would then be to see how well their
views fit the view criticized by Hume at Treatise 1.2.6 (page 11n.8).
Angela M. Coventry
Portland State University
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