A Short History of Modern Philosophy: From Descartes to Wittgenstein, Second Edition (15 page)

Locke proposed a criterion of identity, sometimes described as ‘the continuity of consciousness’. So far as my memories link me to the past and my desires and intentions project me into the future, so far am I the same person over time. Thomas Reid famously objected that such a criterion could deliver two conflicting answers to the question of identity. The old general may remember the young officer, who remembers the boy who stole the apples, even though the boy has been forgotten by the general. So the general both is and is not identical with the boy. But the objection is not lethal and suggests merely that we should amend Locke’s approach. We should define personal identity in terms of a
chain
of interlocking memories, linking the general to all his previous activities: the old man remembers the middle-aged man who remembers the youth who remembers the child. If the chain is unbroken, then perhaps identity is secure.

More serious is the objection made by Bishop Butler. Suppose I have the thought of standing in this room once before. What makes this thought into a
memory
? Surely, the fact that I identify
myself
as standing in this room. But how do I know that this identification is correct? I must have grounds for judging that it was once
I
who stood in this room. False memory claims are no grounds for identity; true memory claims (‘genuine’ memories) are grounds for identity, but only because their truth depends upon the truth of a claim about identity. The criterion, in short, is circular.

Butler’s objection is still much discussed. Locke’s criterion may have an appearance of circularity: but perhaps the circle is not
vicious.
It is vicious only if it presupposes what it sets out to prove; and it is by no means obvious that this is so.

The concept of cause

Throughout Locke’s lifetime the scientific revolution had proceeded unabated. The Royal Society had been founded, and Boyle (1627-1691) had written widely and sceptically of the traditional science, in a way that engaged directly with contemporary philosophical issues. Boyle followed Bacon in rejecting all research into final causes as irrelevant to science; but he was reluctant, in his search for the particular causes of observable phenomena, to take too much guidance from Descartes’
a priori
method, which assumed that fundamental principles could be derived from metaphysics alone. In particular, Boyle rejected the very metaphysical-seeming law that Descartes had put at the heart of his physics: the law of the conservation of motion. This law was to be revived in a new form by Newton, and, when the
Principia
was finally published almost simultaneously with Locke’s
Essay,
philosophers were confronted with an extraordinary synthesis of
a priori
speculation and empirical method, in which seemingly irrebuttable laws were held forth as governing and explaining the whole chaotic world of transient phenomena. It was not until Kant that the philosophical significance of Newton’s theories was finally encompassed. Meanwhile Leibniz vigorously combated Newton’s absolute view of space, while the empiricists occupied themselves with understanding the deep and difficult concept of causality upon which Newtonian physics had been erected.

Locke had already recognised that, in accordance with his principles, it must be possible to give an account of the
experience
from which the idea of causality derives its content. He had no difficulty in resolving this problem to his satisfaction. The exercise of will presents us, he thought, with an experience of causality which is immediate, indubitable and irreducible to anything more basic. In a sense Berkeley followed Locke in this doctrine: that is to say, he thought that in so far as we have an idea of true causality, it can only be one of will, the exercise of which is experienced by us both as an activity and as something suffered. When we observe nature, however, we are confronted by the regular succession of events, but not by any experience of volition. To say that there is a will to attract that draws masses together is to speak in a way that is misleading and unwarranted, since all we can observe is the confluence of masses. If we refer to a law of nature here, then that law is nothing more than the expression of the regular and seemingly immutable fashion in which this motion occurs. (Berkeley thus attacked Newton for speaking of ‘attraction’ or ‘force’ in his theory of gravity, since these terms imply the presence of something more than is strictly observable.)

Berkeley, like Locke, was an empiricist. He believed that everything that we say derives its sense from experience. Since our experience of the relation among things in the ‘external world’ presents us only with regular succession, and not with any spirit or will that animates it, we can mean nothing more when we invoke causal laws, than to refer to this regularity. This theory of Berkeley’s presaged Hume’s radical attack on the traditional concept of causality. It also echoed Leibniz’s theory that causal laws express ‘well-founded phenomena’. It showed the extent to which the concept of causality was becoming uppermost in the minds of philosophers, beginning to take its place as one of the central concepts, indicative of a central problem, in metaphysics.

Berkeley's criticism

George Berkeley (1685-1753), Bishop of Cloyne, was perhaps the greatest of the philosophers to derive his main inspiration from the metaphysics of Locke. He is best known for his idealism, expounded in the
Treatise Concerning the Principles of Human Knowledge
(1710), according to which the world contains nothing but spirits and their ‘ideas’. Berkeley thought that this theory was an ineluctable consequence of the empiricist method that Locke had put forward. Since he accepted that method—and moreover thought that it was the only one that accorded with human common sense—he accepted the consequence. However, his idealism was consequent upon a clearer, though far narrower, presentation of the concept of an ‘idea’ than can be derived from Locke. For Berkeley ‘ideas’ are mental particulars, the immediate objects of the ‘perception’ whereby the contents of our mind are revealed to us, and they comprise all actual mental contents. Images, sense-experiences, thoughts, concepts—all are ‘ideas’ in Berkeley’s sense, since all are immediate objects of mental perception. (Kant was not the only one to complain about this assimilation of items so diverse into a single category. But it was perhaps Kant who made the most telling criticism, in arguing that the empiricists find their conclusions persuasive only because they confuse sensibility and understanding, and so ‘sensualise’ the concepts of the understanding, and misrepresent their nature and function in the derivation of human knowledge.)

Having made this assumption, however, Berkeley went on to draw conclusions which seemed compelling both to him and to many of his contemporaries. First, he attacked Locke’s theory of abstraction, arguing that since everything that exists is a particular, there can be no such thing as an abstract idea. For consider the abstract idea of a triangle: it is supposed to be neither scalene nor isosceles, to have all triangular shapes and no specific triangular shape at once. And is it not an absurdity to think of a triangle that is indeterminate in all its properties? There is an obvious reply: Locke was referring, not to a triangle, but to the
idea
of a triangle; it is ridiculous to suppose that an idea of a triangle is itself a triangle and therefore determinate in its shape. But this reply was forbidden by Berkeley’s assimilation of ideas and images under a single mental category. An image of a triangle in some sense shares the properties of the triangle it represents. Berkeley is right in assuming therefore that there can no more be an abstract image of a triangle than there can be an abstract triangle. And since images are his model for all the ‘ideas’ of the mind, his conclusion must therefore appear correspondingly more plausible.

But why should that assimilation of ideas to images have appeared persuasive? The answer is to be found in Berkeley’s attempt to fill in the gap, left open by Locke’s empiricist theory of meaning, between experience and idea. Berkeley makes experiences and ideas
one and the same:
a perception of a red book, an image of a red book, an idea of a red book— these are all examples of one kind of thing, different in name, but not in nature. Hence there is no difficulty in showing how words are given sense by their application in experience: everything denoted by a word is, in effect, an experience (or idea), and there need never be any doubt in our mind as to what we mean by the words we utter. We need only refer back to the experience which the word denotes. (It is a characteristic of rationalist philosophy to bring all mental processes under one label. But it is also characteristic of rationalism to distinguish very carefully between those ‘clear and distinct’ perceptions which belong to reason and those more confused mental items that display the workings of sense and imagination. For Berkeley such a distinction is empty.)

Idealism

Berkeley feels that he can now provide an answer to the fundamental question of philosophy as he saw it. This is the question of existence. What
is
existence? Berkeley’s first answer is that to be is to be perceived:
esse est percipi.
If everything which confronts us is an idea, then the principle of existence must be found in the nature of ideas. It is absurd, however, to think of ideas as existing outside the mind. And to exist
in
a mind is to be perceived by that mind. Hence, nothing can exist which is not perceived; any metaphysical assertion that commits itself to the existence of an imperceivable thing is absurd. In particular, Berkeley thought, the belief in what he called ‘material substance’ is absurd: this term corresponds to no idea, and therefore has no sense. We do not even know what we mean to assert when we commit ourselves to the existence of that which it purports to name.

This radical conclusion (which Dr Johnson thought he could refute by kicking against a heavy stone) was not, according to Berkeley, repugnant to common sense. On the contrary, it is only metaphysical confusion that could lead the ordinary person to doubt it, since he applies words according to their proper meanings, and therefore affirms existence only of those things of which he has an idea; in other words those things which he experiences. What then are the ‘material objects’ to which we so repeatedly refer? Berkeley refrains from saying that they are
ideas
: for to every table there exists not one but many, perhaps infinitely many, perceptions. Hence the term ‘table’ denotes, not a single idea, but ‘a collection of ideas’. This theory is obscure, as is shown by Berkeley’s answer to the question ‘What does it mean to say that the table exists while I am not perceiving it?’ His answer (in the first instance) is that such an assertion means no more than that, if were to return to the place where the table stands, then I would have a certain perception. In other words, it makes reference not to an actual but to a possible idea. This introduces a complication into Berkeley’s philosophy which he brushes aside somewhat peremptorily, but which has been recognised in recent years as the major source of difficulty for theories such as Berkeley’s: how can there be such entities as possible ideas?

Berkeley’s arguments for his view, in so far as they are not merely reaffirmations of the immediate consequences of his theory of ‘ideas’, consist in spirited, but as it now seems, often misguided, attacks against Locke. Berkeley rejects the distinction between primary and secondary qualities. He thinks that whatever arguments are given for the unreality of the second must equally establish the unreality of the first. He also dismisses Locke’s view of substance, arguing that we can have no idea of the pure ‘substratum’ divested of its qualities, and therefore cannot know what we mean in referring to such a thing. He argues from the subjectivity of ideas directly to the subjectivity of the qualities represented through them, in a manner that betrays his too easy assimilation of thoughts to sensations, and which therefore establishes the inadequacy of the former by reference to the well-known Cartesian arguments for the inadequacy of the latter.

It is now perhaps more apparent than it was to Berkeley’s contemporaries that these negative arguments trade on inapposite conflations and hasty analogies. Berkeley confuses (though the fault is not entirely his) the Lockean ‘substance’ with the material stuff of the physical world; he ignores the distinction between real and nominal essence and uses the word ‘idea’ to name, indiscriminately, qualities, sensations and the concepts which result from them. In short, he fails to present in a cogent manner the issue which really concerns him, which is that of the relation between appearance and reality. His slogan that ‘to be is to be perceived’ might be better expressed as ‘being is seeming’. And the true epistemological weight of his argument can then be seen to amount to this: it is a necessary truth that all my evidence for how things are is derived from my immediate and incorrigible knowledge of how things seem. But I cannot mean, in referring to the world, to refer to a world other than the one that I know (for otherwise I would not know what I mean). So what I speak of, in speaking of objects, is not some underlying reality that lies beyond all my powers of observation, but rather the totality of appearance. In other words, in speaking of objects, I am speaking of the sum of what I can, from my own point of view, observe. My
world
is
my
world. It is not just unverifiable but meaningless to speak of some other world which transcends the world as it appears to me. Since ‘appearance’ or ‘how it seems’ are terms which refer, of necessity, to the mental state of an observer, it seems that the observer has neither reason nor capacity to affirm the existence of things that are not mental.

God and the soul

The real problem that arises for Berkeley, and one which he recognised, was this: how can one accept such a view and escape from the conclusion that all I think and know is contained within the sphere of my own consciousness, so that I have no grounds for asserting the existence of spirits besides myself? This difficulty Berkeley confronted in a manner reminiscent of Descartes. He argues for the existence of an omniscient and omnipotent God who sustains not just the illusion but the reality of a many-souled universe. As Berkeley clearly saw, however, he could not confront the question immediately, without first showing that terms like ‘soul’, ‘mind’ or ‘spirit’ are indeed meaningful according to his own precepts. He admitted some difficulty over this, arguing that the mind is not itself an idea since it is not identical with any of its contents. So do we have an idea
of
the mind? If you take away all the contents of a mind, you do not take away the mind itself, since it is not identical with any of its contents nor with all of its contents taken together. Indeed, the mind seems to be a substance precisely in the Lockean sense: it is an unknowable substratum. Being forced to admit as much, Berkeley found it necessary to say (as though it made things clearer) that we have not an idea, but a ‘notion’ of this substratum. The suggestion is to some extent redeemed by the following observations. First, we do have a unique experience which is associated with the mind: the experience of volition, through which we derive our idea of a
true
causality. Secondly, we can make sense of ‘mental substance’ by extending the maxim that was applied to ideas, that to be is to be perceived, to apply to notions of substance. In this case the maxim becomes: to be is to perceive. It is therefore through the relation of perception that we understand the nature of mind. Perception requires two terms; the reality of one term (the idea) and the reality of the relation (perception) necessitate between them the reality of the other term (the mind). It is as though perception is the hidden ‘bond’ between substance and attribute. Certainly Berkeley’s confusion of ideas with qualities, and his view that substance must contain some active principle and therefore can only be mental, seem to imply some such conclusion.