History of Western Philosophy - Bertrand Russell [369]
His argument against matter is most persuasively set forth in The Dialogues of Hylas and Philonous. Of these dialogues I propose to consider only the first and the very beginning of the second, since everything that is said after that seems to me of minor importance. In the portion of the work that I shall consider, Berkeley advances valid arguments in favour of a certain important conclusion, though not quite in favour of the conclusion that he thinks he is proving. He thinks he is proving that all reality is mental; what he is proving is that we perceive qualities, not things, and that qualities are relative to the percipient.
I shall begin with an uncritical account of what seems to me important in the Dialogues; I shall then embark upon criticism; and finally I shall state the problems concerned as they appear to me.
The characters in the Dialogues are two: Hylas, who stands for scientifically educated common sense; and Philonous, who is Berkeley.
After a few amiable remarks, Hylas says that he has heard strange reports of the opinions of Philonous, to the effect that he does not believe in material substance. 'Can anything,' he exclaims, 'be more fantastical, more repugnant to Common Sense, or a more manifest piece of Scepticism, than to believe there is no such thing as matter?' Philonous replies that he does not deny the reality of sensible things, i.e. of what is perceived immediately by the senses, but that we do not see the causes of colours or hear the causes of sounds. Both agree that the senses make no inferences. Philonous points out that by sight we perceive only light, colour, and figure; by hearing, only sounds; and so on. Consequently, apart from sensible qualities there is nothing sensible, and sensible things are nothing but sensible qualities or combinations of sensible qualities.
Philonous now sets to work to prove that 'the reality of sensible things consists in being perceived', as against the opinion of Hylas, that 'to exist is one thing, and to be perceived is another'. That sense-data are mental is a thesis which Philonous supports by a detailed examination of the various senses. He begins with heat and cold. Great heat, he says, is a pain, and must be in a mind. Therefore heat is mental; and a similar argument applies to cold. This is reinforced by the famous argument about the lukewarm water. When one of your hands is hot and the other cold, you put both into lukewarm water, which feels cold to one hand and hot to the other; but the water cannot be at once hot and cold. This finishes Hylas, who acknowledges that 'heat and cold are only sensations existing in our minds'. But he points out hopefully that other sensible qualities remain.
Philonous next takes up tastes. He points out that a sweet taste is a pleasure and a bitter taste is a pain, and that pleasure and pain are mental. The same argument applies to odours, since they are pleasant or unpleasant.
Hylas makes a vigorous effort to rescue sound, which, he says, is motion in air, as may be seen from the fact that there are no sounds in a vacuum. We must, he says, 'distinguish between sound as it is perceived by us, and as it is in itself; or between the sound which we immediately perceive and that which exists without us'. Philonous points out that what Hylas calls 'real' sound, being a movement, might possibly be seen or felt, but can certainly not be heard; therefore it is not sound as we know it in perception. As to this, Hylas now concedes that 'sounds too have no real being without the mind'.
They now come to colours, and here Hylas begins confidently: 'Pardon me: the case of colours is very different. Can anything be plainer than that we see them on the objects?' Substances existing without the mind, he maintains, have the colours we see on them. But Philonous has no difficulty in disposing of this view. He begins with the sunset clouds, which are red and golden, and points out that a cloud, when you are close to it, has no such colours. He goes on to the difference made by a microscope, and to the yellowness