Locke and Berkeley

 To begin with consider what Locke’s definition of Idea:

“I must here in the Entrance beg pardon of my Reader, for the frequent use of the Word Idea, which he will find in the following Treatise. It being that Term, which, I think, serves best to stand for whatsoever is the Object of the Understanding when a Man thinks . . . or whatsoever it is, which the Mind can be employ’d about in thinking. (ECHU I/i/§8)”

“Whatsoever the Mind perceives in itself, or is the immediate object of Perception, Thought, or Understanding, that I call Idea. (II/viii/§8)”

So Idea is being defined in terms of whatever is present to consciousness when we are perceiving, thinking, imagining something. This does not make the definition circular because Idea is being used as an all-inclusive term for anything that we are thinking at that particular moment. So the object of thought does not have any existence independently of thought; there is no appearance – reality distinction pertaining to the Idea – it’s being consists in being thought. There is nothing wrong with defining Ideas in terms of presence to consciousness because this is an irreducible notion.

But for Locke the sensed object can be abstracted from sensation and can be posited to be an external cause of sensation through inference whose cognitive ground is the sensation itself (only in cases of primary qualities). This abstractionist move is blocked by Berkeley through his ontological principle:

“Whether others have this wonderful faculty of abstracting their ideas, they best can tell: for myself I find indeed I have a faculty of imagining, or representing to myself the ideas of those particular things I have perceived and of variously compounding and dividing them. I can imagine a man with two heads or the upper parts of a man joined to the body of a horse. I can consider the hand, the eye, the nose, each by itself abstracted or separated from the rest of the body. But then whatever hand or eye I imagine, it must have some particular shape and colour. Likewise the idea of man that I frame to myself, must be either of a white, or a black, or a tawny, a straight, or a crooked, a tall, or a low, or a middle-sized man. . . . To be plain, I own myself able to abstract in one sense, as when I consider some particular parts or qualities separated from others, with which though they are united in some object, yet, it is possible they may really exist without them. But I deny that I can abstract one from another, or conceive separately, those qualities which it is impossible should exist so separated. (PHK intr. §10)”

The principle states that the distinction between X and Y is an ontological distinction only if X can be perceived to exist independently of Y and vica-versa; otherwise the difference between the two is a mere semantic distinction. Applying this to the above case the sensed object does not exist independently of the sensation. We can abstract it from the sensation as much as we like but what we cannot do is ascribe this abstraction any ontological distinction. Since the sensed object has no independent existence from the sensation (for e.g. pain is nothing apart from painful sensations) Berkeley’s first premise in justified. The Idea and the Ideatum are defined in terms of presence to consciousness and as incapable of existing independently of one another. In his Commonplace Books he touches on the importance of this innovation:

“Twas the opinion that Ideas could exist unperceiv’d or before perception that made Men think perception was somewhat different from the Idea perceiv’d, that it was an Idea of Reflexion whereas the thing perceiv’d was an idea of Sensation. I say twas this made ’em think the understanding took it in receiv’d it from without which could never be did not they think it existed without. (C 656)”

And,

“I Defy any man to Imagine or conceive perception without an Idea or an Idea without perception . . . Consciousness, perception, existence of Ideas, seem to be all one” (C 572 and 578)

Thus the distinction between consciousness of the sensation and the existence of the sensation is simply a semantic distinction with no ontological consequences. This repudiation of the act-object model of consciousness forms the first step in Berkeley’s proof of idealism.

Coming to premise (2) Berkeley gives the following justification for it in his Dialogues between Hylas and Philonaus:

“Ask the gardener, why he thinks yonder cherry tree exists in the garden, and he shall tell you, because he sees and feels it; in a word, because he perceives it by his senses. Ask him why he thinks an orange tree not to be there, and he shall tell you, because he does not perceive it. What he perceives by sense, that he terms a real being, and saith it is, or exists; but that which is not perceivable, the same, he saith, has no being. (3D234)”

And in PHK 4:

“If we thoroughly examine this tenet, it will, perhaps, be found at bottom to depend on the doctrine of abstract ideas. For can there be a nicer strain of abstraction than to distinguish the existence of sensible objects from their being perceived, so as to conceive them existing unperceived? Light and colours, heat and cold, extension and figures, in a word the things we see and feel, what are they but so many sensations, notions, ideas or impressions on the sense; and is it possible to separate, even in thought, any of these from perception? For my part I might as easily divide a thing from itself. I may indeed divide in my thoughts or conceive apart from each other those things which, perhaps, I never perceived by sense so divided. Thus I imagine the trunk of a human body without the limbs, or conceive the smell of a rose without thinking on the rose itself. So far I will not deny I can abstract, if that may properly be called abstraction, which extends only to the conceiving separately such objects, as it is possible may really exist or be actually perceived asunder. But my conceiving or imagining power does not extend beyond the possibility of real existence or perception. Hence as it is impossible for me to see or feel anything without an actual sensation of that thing, so is it impossible for me to conceive in my thoughts any sensible thing or object distinct from the sensation or perception of it.”

Berkeley consistently insists that he is not changing anything but is with the common man in his proof for idealism because he is merely making plain the meaning of the word ‘existence’. Philosophers preceding Berkeley had made a division in the sense of existence in order to make it more precise. The criteria for existence was causal efficacy and the only properties or qualities that survived this criteria were primary qualities like shape, size, mass, power etc. We cannot think of an object devoid of these qualities but an object can exist without colour and hence this quality is not on a par with others more essential to an object. Also primary qualities are essential ingredients in the endeavour to explain the causal efficacy of an object. Hence the sense in which the former exists is different from the sense in which the latter exists. Also the former qualities are stable and constant whereas colour is an inconstant quality; an object seems to be of a different colour in broad daylight compared to when it is in shade or when some reflection is falling on it and in complete darkness the colour is not perceived at all. Hence there is a double sense of existence – one that can be applied to primary qualities which is the sense in which something external to the mind is said to exist and secondary qualities which have a mind-dependent existence and are hence observer relative. Berkeley repudiates this picture to form a single sense of existence which is more in keeping with the practices of the vulgar.

The meaning of existence is to be determined in terms of what meaning it has for us. The meaning it has for us is revealed through actual sensation which is understood not only in terms of presence to consciousness but as being inseparable from its consciousness. While in the rationalist tradition meaning or definition of something depended on whether we can conceive it without contradiction – which principle itself is derived from the Principle of Non-Contradiction and is made manifest through principle like Nothingness has no properties therefore if there is something then it possesses some property or other. But Berkeley’s empiricism begins not with rational principles but with asking what Ideas we have and all Ideas are intimately tied to sensations. So if we have to clarify the meaning of existence then we will have to look at the sensation or impression through which we acquire the notion of existence. This project of tracing the origin of ideas back to their source in sense-impressions are begun by Locke but it was made concrete through Berkeley and completed later by Hume. Why Berkeley’s case for tracing the source of the concept of existence to the actual sensation is stronger than Locke’s can be understood from the fact that Locke’s critique of innatism is vulnerable to Rationalist counter-arguments that even if sensation is required to acquire the notion of existence that does not imply that the meaning or definition of existence itself depends on this source. This practically was the retort Locke got from Leibniz’s New Essays Concerning Human Understanding.

But Berkeley is not similarly vulnerable. The reason is that firstly Berkeley has tightened up his case through his use of the separability principle which allows him to define the existence of the sensed object to sensation itself. Thus sensation is not a representation of something external but is a reality in itself. It is both the sensation and what is sensed. The inference to external sensed object is blocked on this way to understand sensation. Secondly it is important to understand that if Berkeley can show that the psychological means through which a concept is acquired contributes to the content of that concept then rationalism is undermined. Thus sensation does not simply reveal the meaning of existence but determines or constitutes that meaning. Hence the meaning of trees, grass etc. that the gardener learnt has as its necessary component the sensation of trees, grass etc. and thereby what he means that trees etc. can exist unperceived is that currently he has not sensation of trees and grass. As a consequence just as pleasure and pain cannot be predicated of external objects regarded as the cause of pleasure and paid similarly the application conditions of a concept is similarly limited to the consciousness which is the defining feature of that concept and thereby the concept of existence is restricted to the purview of actual sensations and cannot be applied to external non-sensory objects for that would be as Berkeley says in PHK 4 ‘a manifest contradiction’. This interpretation is further supported by a passage that has troubled commentators but which otherwise is amenable to be understood through this interpretation:

“But say you, surely there is nothing easier than to imagine trees, for instance, in a park, or books existing in a closet, and no body by to perceive them. I answer, you may so, there is no difficulty in it: but what is all this, I beseech you, more than framing in your mind certain ideas which you call books and trees, and at the same time omitting to frame the idea of any one that may perceive them? But do not you yourself perceive or think of them all the while? This therefore is nothing to the purpose: it only shows you have the power of imagining or forming ideas in your mind; but it doth not show that you can conceive it possible, the objects of your thought may exist without the mind: to make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest repugnancy. When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas. But the mind taking no notice of itself, is deluded to think it can and doth conceive bodies existing unthought of or without the mind; though at the same time they are apprehended by or exist in itself. (PHK I §23)”.

We can see the process through which we have reached this point. First Locke defines idea as whatever is the object of thought or consciousness. Them he considers the status of the existent object or the sensed object in the sensation or the Idea. Since Locke does not ascribe to separability principle he takes the existence of the object of consciousness to be inseparable from consciousness (appearance = reality principle) on grounds of his the nature of mind being a substance which cannot apprehend anything apart from its modes. But he allows through a process of abstraction the extraction of the sensed object (in case of primary qualities only) from the sensation and through inference posit its existence as an external reality. Then Berkeley comes into picture and through his separability principle he blocks this abstractive move confirming the definitional identity of the sensed object and the sensation thereby espousing a psychologism which though implicit in Locke was not endorsed by him or even intended by him. This radically changes the nature of the debate between rationalism and empiricism; something that Hume realized, as he says in his Treatise 1/1/1:

“’tis remarkable, that the present question concerning the precedency of our impressions or ideas, is the same with what has made so much noise in other times, when it has been disputed whether there be any innate ideas, or whether all ideas be derived from sensation and reflexion. We may observe, that in order to prove the ideas of extension and colour not to be innate, philosophers do nothing but show, that they are conveyed by our senses. To prove the ideas of passion and desire not to be innate, they observe that we have a preceding experience of these emotions in ourselves. Now if we carefully examine these arguments, we shall find that they prove nothing but that ideas are preceded by other more lively perceptions, from which they are derived, and which they represent.”