A Short History of Modern Philosophy: From Descartes to Wittgenstein, Second Edition (14 page)

Ideas and words

Like Hobbes, Locke attached his empiricist account of the origin of ideas to a theory of meaning. He was motivated by a belief that scholastic and Cartesian philosophy achieve their interesting results largely by assuming that certain key terms have a meaning and that the meaning is understood. On examination, however, these terms are often found to have a meaning other than the one intended, or sometimes no meaning at all.

Words have meaning, according to Locke, because they are the ‘signs’ of, or ‘stand for’, ideas. (Not much of a theory, of course, since ‘sign’ and ‘stand for’ are precisely the terms that need to be explained by a theory of meaning.) Communication is the process whereby words, which are attached to ideas in my mind, issue from my mouth and impinge on your ear, so causing the same ideas to arise in your mind.

The theory is open to serious criticism. In particular, it confuses the relation of meaning, which is governed by rules and conventions, with the natural relation between a word and the ideas that are aroused by it. The word ‘cow’ conventionally signifies a certain kind of animal; but it arouses in many people the ideas of milk, farmyards and pasture. Laurence Sterne put the criticism in a nice piece of satire:

—My young master in London is dead! said Obadiah—

—A green satin nightgown of my mother's, which had been twice scoured, was the first idea which Obadiah's exclamation brought into Suzannah's head.—Well might Locke write a chapter on the imperfection of words.—Then, quoth Suzannah, we must all go into mourning.—But, note a second time: the word
mourning,
notwithstanding Suzannah made use of it herself, failed also of doing its office; it excited not one single idea, tinged either with grey or black,—all was green.—The green satin nightgown hung there still.
(Tristram Shandy,
Book 5, chapter 7).

One of the achievements of modern philosophy, an achievement which is owed largely to Wittgenstein, is that it has taken the point of such satire seriously. It has given proper foundation to the view of language as a practical skill, governed by conventions which need make no reference to such accidental occurrences as Locke’s mental ‘ideas’. It could be further objected to Locke that, on his own account of what an idea is, I could never know that you mean the same by a word as I do. In particular, the idea that I associate with the word ‘pain’ might be associated by you with the word ‘pleasure’; this difference between us lying as it were undisclosed beneath the mask of our common usage. Such a theory, which removes from meaning its essential ‘publicity’, would for this reason now be almost universally rejected.

The physical world

It remains now to state briefly the view of the world and of scientific enquiry that Locke derived from his theory of knowledge. In many respects this view reflected an improved theory of the nature of science; some aspects of it have indeed been restored to favour in recent years as scientists have come to understand their utility. Locke derived from his friend Robert Boyle and ultimately from Pierre Gassendi (1592-1655) an interest in the distinction between primary and secondary qualities. He also enquired—in a wholly novel and illuminating way—into the concepts of essence and substance, endeavouring both to reinstate them as fundamental scientific notions, and at the same time to free them from the metaphysical confusion introduced by rationalist ways of describing them. In this he made a philosophical step the significance of which was unappreciated for over two centuries.

Among complex ideas Locke distinguished those of modes, substances and relations. These correspond to the grammatical categories of predicate, subject and relation. As he sometimes seemed to recognise, however, it is not right to say that we have an idea of the individual substance. Part of the obscurity in the theory of abstract ideas comes about because all ideas seem to be inherently general: that is, they represent properties, of which it would make sense to say that more than one object possesses them (just as more than one person may exactly correspond to the image in a painting). How then do we arrive at a conception of the individual thing which is the subject of predication? Locke was anxious to avoid the paradoxes of Spinozism, and to preserve a notion of substance that allowed for the existence of many—possibly infinitely many—substantial things. So he could not take refuge in the Cartesian idea of substance.

It is first necessary, Locke thought, to distinguish ideas from qualities; qualities being the
powers
of objects to produce ideas in us. Primary qualities are supposedly both inseparable from the objects in which they inhere, and also generative of simple ideas. They are the qualities of extension, motion, mass and so on, and are the true subjects of scientific investigation. Secondary qualities are nothing but certain powers to produce sensations (the power of sugar to produce a sweet taste, of red things to produce certain characteristic visual impressions, and so on).

It is difficult to be precise about this distinction (which could be drawn differently for different purposes). But one assertion that Locke makes about it is certainly of crucial significance, both historically and philosophically. Whereas primary qualities resemble the ideas that are produced by them, secondary qualities do not. And this enables us to say that there is a sense in which primary qualities are really
in
the objects which possess them, whereas secondary qualities are not. Berkeley objected to this, saying that it is absurd to suppose that any quality of a material substance can resemble an idea, since ideas are mental entities, belonging to a wholly different realm, and it is
prima facie
absurd to suppose that ideas can resemble things which are not ideas.

In order to reply to this objection, we must attempt once more to free Locke’s insight from the dead theories which enclose it. We must recognise that, in speaking of a resemblance between ideas and qualities, he was misdirecting his thoughts in a way encouraged by his theory of meaning. In some sense, as Locke saw, certain scientifically determinable and measurable qualities are basic to the reality of a thing in a way that other qualities are not. The secondary qualities seem to stand in need of a perceiver, the primary qualities only in need of an object. One way of putting the point is this: if you know all the primary qualities of an object, and the nature of the man who perceives it, then this alone will enable you to explain how that object appears to him. There is no need to refer to the secondary qualities of the object in order to explain how it is perceived. The primary qualities can be said to resemble our perceptions of them in the sense that they themselves must be invoked in explaining that perception. To say this is to deny not the reality of secondary qualities, but only their centrality in any scientific view of the nature of the object that possesses them.

Real and nominal essence

Seen in this way, the distinction between primary and secondary qualities relates to another of Locke’s distinctions, that between real and nominal essence. Locke makes this new distinction in the course of exploring the nature of material things, and in subjecting the scholastic ideas of ‘substance’ and ‘essence’ to critical examination. If we construe ‘substances’ to be individual things, the bearers of qualities, then we can have no positive conception of them. They are the ineffable substrata which ‘support’ those qualities through which any object is known. Any positive conception of the individual is the idea of a quality and therefore not of the substratum itself.

Let us leave aside the (for Locke) extremely difficult question how we might then come to have such an idea as that of substance. Locke, in common with many philosophers, influenced directly or indirectly by Aristotle, recognised that such a negative conception leaves us with the task of defining the nature of an individual. An individual cannot be identified as a particular substance (even if it is identical with such a substance) since of substances, considered in isolation from their qualities, nothing can be said. As the scholastics put it,
‘individuum est ineffabile
^,
(‘the individual is ineffable’), a doctrine which Locke in the end is driven to support. It is therefore necessary to separate among the properties of a thing those which define its essence from those in respect of which it might change without changing its nature. This is the closest we can get to the idea of an individual.

But what is this essence? In fact, Locke now speaks not of individuals but of kinds. The scholastic idea of an individual essence seemed to him to be incoherent. He regarded all problems of individuality as exhausted by enquiries on the one hand into the fundamental kind to which an individual belongs, and on the other hand into the conditions of its identity. Except for the general idea of a ‘substratum’ there was nothing to be said by way of characterising the nature of a thing. And it is possible to doubt that Locke’s empiricist theory of meaning could give him grounds for the assumption even of this ‘general’ idea of substratum. It seems absurd to suggest that we arrive at this general idea by abstraction, since abstraction would have to go so far in such a case as to leave us, so to speak, with no remainder.

As I implied, Locke’s purpose in exploring the concept of essence is partly polemical. He wished to attack the Aristotelian science which had erected itself upon a system of rigid classifications. These classifications seemed to be conceived
a priori
and without reference to the actual constitution of the objects which fall under them. For Locke, the only significant idea of essence must be one of constitution. The constitution of an object cannot be determined by fiat, but only by exploring the reality of the thing itself. Hence it cannot be determined
a priori.
Locke therefore introduced the idea of a real essence, to be distinguished from the nominal essence bestowed on an object by the arbitrary classification under which we subsume it.

Consider the classification ‘bachelor’. This defines a nominal essence, which is to say, a set of properties which we consider to be the qualifying attributes of the class of bachelors. The classification is arbitrary; we could have defined the word differently. But in so far as it exists it enables us to speak of a certain ‘essence’. We can say, for example, that it is an essential feature of a bachelor that he is unmarried, meaning that,
qua
bachelor, he is of necessity unmarried. But it is not an essential feature of John, who is a bachelor, that he is unmarried: on the contrary, he might choose to marry tomorrow, in which case, in ceasing to be unmarried, he ceases also to be a bachelor. Nominal essences are therefore accidents of classification; they reflect constraints embedded in our language, but these constraints do not operate on the things themselves. They hold, as the medieval logician would have put it, not
de re
but
de dicto.
Locke thought that it is only nominal essences that could be known
a priori,
and this is only because such knowledge would be the empty reflection of our own linguistic habits, not knowledge of the things themselves.

Now consider the classification ‘gold’. This is associated, according to Locke, with a nominal essence—gold is a yellow, metallic substance, etc. But gold has a real essence as well, in respect of which it could not change without ceasing to be the kind of stuff that it is. This real essence is not (unless by some extraordinary accident) given by the nominal essence. It has to be discovered by scientific investigation. The nominal essence guides us in that investigation only to be overthrown by it. As a matter of fact, Locke was inclined to think that real essences are unknowable. This was partly because he thought that the underlying reality of material substances must remain hidden from observation. Since his day we have found reason to reject that belief. We might come to the conclusion that what really matters to something’s being gold is, for example, its atomic weight, and not those properties in which we first based our classification. Hence empirical enquiry can decide the real essence of gold: the matter, however, could never be settled by convention.

In the case of modes, and of simple ideas (in other words in the case of the ideas corresponding to qualities), real and nominal essence cannot be distinguished. It is only in the case of substances that the distinction can be made. But as the example indicates, there are definite ‘kind’ terms—such as ‘gold’—which admit of the distinction. Do they therefore denote substances? Surely not—at least, not in the sense Locke intended. Gold is not an individual thing, but a stuff. In other words, it is a substance in the more familiar, common sense of the term. And now we begin to see, what neither Locke nor the rationalists were equipped to see, that real essences belong not only to individuals but also to kinds.

Personal identity

Locke’s explorations of the concept of essence did not provide a satisfactory account of the nature of individual substances. He came to realise that the concept of identity must play an important part in distinguishing individuals from kinds. He made suggestions as to the deep intrinsic connection between the individuation of a thing and its location in space and time; but his most important contribution in this area was to raise the problem of personal identity in its modern form. Locke argued that to be a human being is one thing, to be a person is another. Human beings can endure where a person ceases, and perhaps vice versa. A human being is an organism, whose identity is determined by the continuity of that organism in accordance with the real essence which it possesses. But the organism is not identical with the person; men can suffer radical changes of personality; or we can imagine a personality that, after enduring in one organism, suddenly disappears to reappear simultaneously and intact in some other, erstwhile sleeping body. Many thought-experiments can be performed which will point to the conclusion that identity of man and identity of person are separate ideas. In which case, in what does the identity of a person consist?