LOCKE AND METAPHYSICAL DUALISM
José Luis Bermúdez
Metaphysical dualism is not a topic that receives much attention in Locke’s Essay.
In one sense this
is rather surprising, given that so many of his contemporaries and near-contemporaries were
preoccupied with the case for and against Cartesian dualism. In another sense, however, the lack of
discussion seems all too natural a consequence of his scepticism about the possibility of gaining
knowledge of real essences. If we can know only nominal essences and never what really lies behind
them (the “real internal, but generally in Substances unknown Constitution of Things, wheron their
discoverable Qualities depend”
), then it seems pointless indulging in the sort of speculation
required to come out either for or against Descartes’ position. Nonetheless, just as Locke’s official
position on the unknowability of real essences did not prevent him from tentatively espousing the
“corpuscularian Hypothesis” (IV, iii, 16), nor did it stop him from occasionally engaging with
There are commentators who hold that Locke not only engaged with dualism, but was in fact a
dualist himself. Aaron is one. He describes Locke's views as ". . . the traditional ones, accepted by the
Church and upheld by Cartesianism".
Following traditional ways of thinking Locke regards the mind as a substance, but a
substance which is immaterial. He accepts the usual dualism, the 'two parts of nature',
active immaterial substance and passive material substance. . . It is a fundamental
point with him that the universe cannot be explained in terms either of matter alone or
of mind alone.
Roger Woolhouse is a more recent commentator of the same opinion:
What Locke says about body and mind is said against the background of Descartes’
dualism. Generally he accepts that, besides God, there are two distinct kinds of thing,
material substance or body, and immaterial substance or mind or spirit.
References to Locke's
Essay Concerning Human Understanding
will be to the Nidditch edition
(Oxford: Clarendon Press, 1975). They will take the usual form, so that 'II, ii, 2' should be read as
'Part Two, Chapter Two, Section Two'.
III, iii, 15.
Richard I. Aaron,
, (Oxford: Clarendon Press, 1955, second edition) p.143. Aaron notes,
of course, that Locke's views on the essence of the mind were far from Cartesian, given his denial of
the Cartesian thesis that the mind is always thinking.
R. S. Woolhouse
(Brighton: Harvester Press, 1983) p.180. In the remainder of this paper I
will follow Woolhouse in bracketing God’s status as an immaterial thinking substance. In referring to