Is Locke a conceptualist or a nominalist? Numerous
supporters of these two opposing interpretative hypotheses are to be found
amongst scholars and Locke's concept of universals is the subject of
reconstructions which often differ greatly.
In a situation of this sort, it is easy to yield to the temptation to
attribute the origin of the divergence to a purely terminological
ambiguity. Perhaps the word "nominalism" is understood in
different senses? Apparently not. Almost all writers, explicitly or
implicitly, agree in considering nominalism to be a doctrine according to
which universals exist only as names which are used to designate
collections of concrete individuals. Thus, according to nominalism, there
is neither correspondence between universal terms (common nouns) and
entities which exist in reality, nor with abstract, universal ideas
existing in the mind. In modern philosophy the positions of Berkeley and
Hume are generally considered nominalist.
According to various scholars, Locke's position is essentially the same as
the nominalism of Berkeley. This interpretation is based principally on
Locke's assertions in paragraph 9, chapter xi, Book II, of An Essay
Concerning Human Understanding. If one considers this paragraph in
isolation from the rest of Book II and, especially, from the content of
Book III, the following conclusions may be drawn:
a) Notwithstanding Locke's numerous references to the possession and
awareness of abstract or general ideas on the part of the human mind,
these abstract ideas are none other than particular ideas used as
representatives of or signs standing for a class of individuals: what is
universal is only the name.
b) The abstraction to which Locke refers corresponds to that which the
Scholastics called "improper" or distinguishing, which consists
in mentally separating a characteristic, a quality or a part of a known
thing from all of the others contemporaneously perceived; this kind of
abstraction is radically different from that which is "proper"
or non-distinguishing and which allow us to experience the (universal)
nature or essence in the perception of the particular.
c) Locke's conception of abstraction would not therefore be incompatible
with that of Berkeley; on the contrary, Berkeley's attribution to Locke of
a belief in the existence in the mind of general, abstract ideas in
reality distinct from particular ideas would seem a polemical exaggeration.
These considerations would make plausible Locke's classification as a
nominalist. In my opinion, this would be an incorrect and inadequate
interpretation of Locke's philosophy, based upon an arbitrary isolation of
the text cited above from the rest of An Essay Concerning Human
Understanding. It should be noted that:
1) The principal aim of Book II is to demonstrate that all of man's ideas
come from experience and that
complex ideas are based upon the simple ideas due to sensation and
reflection, which are compared and combined by operations of the mind.
From this point of view, the distinction between particular and universal
ideas is of marginal importance. In fact, Locke warns at the beginning of
Book I that he will use the term idea "to express whatever is meant
by phantasm, notion, species, or whatever it is which the mind can be
employed about in thinking" (I,1,8), and hence includes in the
semantic category "idea" both individual mental representations
(images and phantasms) and universals (notions and species).
2) As Locke explicitly states, the examples given in chapter xi of Book II
(which deals with mental
operations), "the instances I have hitherto given have been chiefly
in simple ideas"; chosen, that is, for the purpose of clarity and to
further the aim of Book II, with the explicit warning that "Of
compounding, comparing, abstracting, etc., I have but just spoken, having
occasion to treat of them more at large in other places" (II,xi,14).
I will try to demonstrate that although for Locke abstract ideas are the
connection between general terms and particular things (which are known by
means of ideas), it is clear that the link cannot be identified with
either of the two elements which it connects: an abstract idea cannot be a
particular used as though it were a universal. In other words, that which
determines the universality of an abstract idea for Locke is not simply
its relation with a number of particular ideas, as for Berkley, but
something inherent in and characteristic of the idea itself, the nominal
essence which distinguishes all complex ideas (all kinds of complex ideas:
of modes, relations and substances).
I do not think that there are evident contradictions between the examples
of abstraction given in Book II and the broad theory of language presented
in Book III. There is simply a difference of approach and aims and thus,
in the final analysis, a complementarity.
Equally widespread amongst scholars is the legend according to which Locke
shows a strong aversion to abstract ideas, similar to that of Berkley in
the Treatise. This legend is endorsed by influential commentators on
Locke. A. C. Fraser writes: "Locke has everywhere a sober dread of
abstractions, and clings to the particular and concrete, with a sense of
the risk of losing the real in the emptiness of the universal". In
reality this supposed aversion does not exist; on the contrary, Locke does
not even propose the reduction of ideas to "mental pictures" (a
reduction which in Berkeley and Hume will form the base of the negation of
the existence of abstract ideas in the mind).
Locke is not in the least afraid of abstract ideas; his constant concern,
which is evident in his treatment of the complex question of the relation
between real and nominal essence, is to refute the position of the
Scholastics, according to which a universal concept in the mind (post rem)
reflects the universal present in all things as substantial form (the
universal in re), without assuming positions which are purely
conventionalist and nominalist with regard to knowledge, such as those of
Mersenne, Gassendi, Hobbes and sceptical and anti-Cartesian free-thinkers.
To show this, I shall offer a careful analysis of the relation Locke makes
between real and nominal essence, with regard to the relations which link
term to idea and idea to things. For Locke, the term is the sign (mark) of
an abstract idea and the idea itself is the sign of a plurality of things.
The nature of the relation between signifier and signified is variable,
though, in the relation between ideas and things with respect to the
various kinds of complex ideas which the human mind may frame. The
greatest difference is to be found between complex ideas of mixed mode and
complex ideas of substance. With regard to ideas of substance in
particular, Locke's thought is interpreted in different and often
contradictory ways. Although complex ideas of substance may be reduced to
a collection of simple ideas, Locke does not doubt the existence of
"the real internal, but generally (in substances) unknown,
constitution of things, whereon their discoverable qualities depend"
(III,iii,15). The reference of the idea (universal) to things is uniquely
determined by the nominal, not the real, essence. Locke insists that
nominal essences are not arbitrary because the mind, in forming its
complex ideas of substances "only follows nature" and does not
join together ideas which do not have a natural connection.
For Locke, man uses a certain discretion in constructing nominal essences,
since he chooses perceived qualities considered characteristic of a
substance, but this discretion is not arbitrary or unconditional because
it is limited to the occurrence of empirically verifiable properties,
increasingly so by the growth of the scientific knowledge of nature,
although clearly this discretion is never completely eliminated since
human knowledge may always be perfected. In Book II, Locke asserts that
ideas of substance are all inadequate because they all lack "something
we should be glad were in them", since "desiring to copy things
as they really do exist, and to represent to ourselves that constitution
on which all their properties depend, we perceive our ideas attain not
that perfection we intend" (II,xxxi,3), but this perfection (the
complete identity of real essence and nominal essence) may never be
reached. On the other hand, complex ideas of mixed mode and of relations
are always adequate (for Locke an idea is adequate if it represents
perfectly the archetype on which the mind supposes it is based).
One may ask a fundamental question: this unknowability of real essence of
a substance which has been asserted on numerous occasions, is it an
unknowability in principal (absolute impossibility) or an unknowability in
practice, due to the limitations of science at the time?
Although the question cannot be resolved once and for all, I am convinced
that from the overall spirit of the Essay there emerges the idea that
human knowledge tends to conform to an objective structure of reality;
even though Locke is aware that the complete identity between nominal and
real essence is impossible in practice with respect to the knowledge of
substances, he remains convinced that this identity constitutes the limit
and the ultimate goal of the quest for knowledge.
There is, in effect, in Locke's thought a break with the Cartesian view of
science: mathematics and demonstration are no longer the only privileged
model of knowledge; experiment regains the essential role that Descartes
denied it. For Locke, who was a great admirer of Newton, mechanical
explanation remains the ideal model for a scientific explanation, but is
not always - in practice - possible (Boyle was also convinced of this) and
so the knowledge of nature assumes a merely probable status, having been
reached by the process of induction, in contrast to mathematics and ethics
which are completely deductive. In fact, Boyle's research and methods had
a profound influence on Locke's conception of science and in particular on
the doctrine of the knowledge of substances. These observations on Locke's
philosophy of science underline the enormous, unbridgeable distance
between it and that which Berkeley was to formulate in De Motu in 1721 (defined
as "instrumentalist" by K. Popper, as opposed to the "essentialism"
of Newtonian physics).
In conclusion, in opposition to other widespread opinions, I will seek to
demonstrate that: 1) Locke's concept of abstraction is fully compatible
with conceptualism and may in no way be considered nominalist; 2) Locke's
complex theory of knowledge cannot be considered a conventionalist view of
Furthermore, the profundity of Locke's concept of substance with regard to
the science of his time will clearly emerge, so as to make evident the
inadequacy of Hegel's judgement in conclusion of his comment on the
distinction between real and nominal essence in Locke, which finishes with
the famous phrase: "This (philosophising) is a very commonplace
account of the matter".