The Philosophy
Bishop George Berkeley is the second of the three British Empiricists. His main work, A Treatise Concerning the Principles of Human Knowledge, Part 1, is a concise, very readable argument for idealism and immaterialism. Berkeley’s central philosophical idea is his rejection of the theory of matter; i.e. that there can be a substance which exists independently of a perceiving mind.
Abstract Ideas
The Introduction of the Treatise is a sustained criticism of the notion of abstract ideas, which he thinks are responsible for all manner of confused and unclear thinking. Abstract ideas are formed when we take qualities or modes of things and consider them apart from the object in which they are found. Berkeley’s argument is that abstract ideas don’t exist; that is, it is impossible to actually formulate a coherent idea in the mind, of an abstraction. The reason is that the abstract idea is an idea which, by definition, lacks any qualities. The abstract idea of colour, for example, lacks colour, and that of extension is a type of extension “which is neither line, surface, nor solid, nor has any figure or magnitude” (Introduction, sect. 8).
Esse est Percipi
The whole of George Berkeley’s philosophy is centred on the phrase, esse est percipi (to be is to be perceived). In the same way that thoughts, passions, and imagined ideas can’t exist without the mind, “to me it seems no less evident that the various sensations, or ideas imprinted on the Sense… cannot exist otherwise than in a mind perceiving them.” (Part First, sect. 3)
This seems outrageous at first glance, but upon closer inspection, may appear less so. There are basically two ways of approaching this idea. In the first, Berkeley simply asks us not to make inferences where we have no solid grounds for doing so. What are bodies, as far as we know? The bodies we perceive are, in truth, nothing more than sensations impressed on our minds. If we really wish to ground our philosophy only on what we know for sure, and resist the temptation to speculate about the way things might be, this is all we reasonably claim. Descartes, for example, upon noting the ideas excited in his mind by his senses, went on to postulate the existence of some form of extended substance (matter) as the cause of these ideas. If he had remained true to his method of doubt, he would have stopped at the ideas and refused to speculate about possible causes.
The second way is to reflect on whether we can really conceive of a body existing without a perceiving mind. Berkeley isn’t asking whether we can simply imagine a body without any perceiving witnesses; rather, he’s asking if the idea of a body without a perceiver is coherent. A body that we perceive is not just a body; it’s a body that we perceive. Bodies never, in actual fact or as far as we know, appear without an observer.
Primary and Secondary Qualities
Berkeley takes up Locke’s distinction between primary and secondary qualities; the former including extension, figure, motion, rest, solidity or impenetrability, and number; the latter, all sensible qualities such as, colour, sound, taste, etc. It is held to be uncontroversial that secondary qualities don’t exist without the mind; i.e. unperceived, but primary qualities are supposed to “exist without the mind, in an unthinking substance which they call Matter.” (Part First, sect. 9)
This is a distinction that has carried forward to today. Scientists (and most of the rest of us) believe that there is no colour ‘out there’ in the world. There are only electromagnetic waves of varying lengths which our brains interpret as colour. This is analogously true for all other sensory qualities. Primary qualities, on the other hand, like extension, are held to really exist in matter, which is independent of any perceiver. Berkeley challenges this assumption, arguing that inasmuch as we deny secondary qualities external, independent reality, we ought to do the same with primary qualities.
One way Berkeley argues for this is by suggesting that primary and secondary qualities are inseparable, hence the former cannot be abstracted from the latter. There is no such thing as a real, extended body that lacks secondary qualities. Wherever we find the one, we must therefore find the other, and since it is acknowledged that secondary qualities exist only in the mind of a perceiver, that must be where we find primary qualities as well.
Epistemology
Berkeley identifies three objects of human knowledge, or ideas; those which come to us from our senses, those we obtain from reflecting on our mental operations and emotions, and those formed from memory and imagination.
Of these three sources of knowledge, the last two are explained/caused by the normal operation of our minds. Ideas caused by sensation, however, don’t fall into this category. They differ from these in two main ways. First, they are more vivid and constant (as in the difference between a real table and one merely remembered or imagined), and second, they are not subject to our whims (I can imagine anything I wish, whereas sensations force themselves on me). They therefore have a different source (which will turn out to be God (see the ‘Religion’ section below)).
Finally, ideas are passive. They therefore, in contrast with conscious agents (which Berkeley calls, somewhat misleadingly to the modern ear, spirit, soul, mind, or myself) which are active and willing, cannot be the cause of anything.
Refutation of Scepticism
It may seem as if Berkeley’s principle leads directly into radical scepticism (which is exactly where David Hume took it). After all, he seems to be saying we ought not to inquire beyond what sensation presents us with; rather, we should just be content with these ideas and halt our investigations there. In fact, Berkeley actually thought his philosophy refutes scepticism.
Before Berkeley, it was received wisdom (a la Descartes) that Mind and Matter were separate substances. This gap was only bridgeable (i.e. knowledge was only possible) because the mind creates representations of physical matter. The scepticism lies in the fact that since we only have access to the internal representations the mind produces, we can never be certain they correlate with external reality. Berkeley overcomes this problem because he denies the existence of any external reality in the first place. Out internal ideas can’t possibly be mistaken because those internal ideas are the whole story.
Ontology
One immediate consequence of Berkeley’s principle is that matter, as some corpuscular, perceiver-independent substance, doesn’t actually exist. If bodies are simply ideas in a mind, the physical, as we typically conceive of it today, isn’t real. This means that there is only one substance in existence; what Berkeley called spirit or mind, but considering his definition, “that which thinks, wills, and perceives” (Part First, sect. 138), we might better recognise as consciousness.
In addition, Berkeley thinks there are two types of ‘spirit’. The first is human, while the second is God. We will discuss God in the section on ‘Religion’ and look at human minds next.
Human Spirit / Mind
Berkeley doesn’t talk a lot about mind in the Treatise but he does tell us that minds are simple, undivided substances that are active in two respects. The first is in their capacity to perceive ideas. This Berkeley calls understanding. The second is the way they produce and otherwise manipulate or use ideas, and this he calls will.
Berkeley doesn’t have much to say regarding the problem of other minds in the Treatise either. All he says is that we can only be aware of the existence of other human minds through inference. Our knowledge of other people is therefore not immediate (and presumably, therefore, not certain).
Cause and Effect
Matter doesn’t exist. The only things that exist are minds and the ideas those minds have. Ideas, we have seen, are passive, while minds are active. Since ideas are passive, it is impossible that one idea could affect either another idea or another mind. Yet, we see causal relations between passive objects (ideas of sensation) all the time, as in when one billiard ball strikes another causing it to move. How does Berkeley explain this?
For Berkeley, the connection we see between ideas of sensation is not a causal one; rather, the effect is a mark or sign that something has happened. One example Berkeley gives is of a noise; “the noise that I hear is not the effect of this or that motion or collision of the ambient bodies, but the sign thereof.” (Part First, sect. 65) These significations are orchestrated by God for our benefit, so that we may understand the laws of nature, which are simply the way God has arranged the universe (see the ‘Religion’ section for more on this).
Religion
Bishop Berkeley was a devout Christian and much of his work was directed against ‘freethinkers’ and ‘atheists’, whom he saw as representative of the spiritual decay the England of his day was plagued by.
Given his somewhat unique metaphysics, Berkeley has an interesting argument for the existence of God. We have already seen that we don’t produce the ideas we get from sensation. Since ideas are passive, they cannot be the cause of themselves, and since matter doesn’t exist, it can’t cause them either. Where then, do ideas of sensation come from? God.
Berkeley offers three arguments against the problem of evil. First, he claims that since God created the universe in accordance with a set of “the most simple and general rules, and after a steady and consistent manner” (Part First, sect. 151), some negative outcomes were unavoidable. Second, the “blemishes and defects of nature” (Part First, sect. 152) enhance the good, by contrast. Finally, he thinks we incorrectly judge things ‘evil’. If we “enlarge our view, so as to comprehend the various ends, connections, and dependencies of things… we shall be forced to acknowledge that those particular things which, considered in themselves, appear to be evil, have the nature of good, when considered as linked with the whole system of beings.” (Part First, sect. 153)
Berkeley also argues for the immortality of the soul by recalling the distinction between bodies and spirits. The former are passive ideas in the mind, while the latter is “indivisible, incorporeal, unextended; and… consequently incorruptible.” (Part First, sect. 141)