Bertrand Russell on George Berkeley

“Berkeley, after abolishing matter, is only saved from complete subjectivism by a use of God which most subsequent philosophers have regarded as illegitimate.”

“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.”

“In the second Dialogue Philonous sums up the discussion, so far as it has gone, in the words: “Besides spirits, all that we know or conceive are our own ideas.” He ought not, of course, to make an exception for spirits, since it is just as impossible to know spirit as to know matter. The arguments, in fact, are almost identical in both cases.”

“Berkeley’s argument consists of two parts. On the one hand, he argues that we do not perceive material things, but only colours, sounds, etc., and that these are “mental” or “in the mind.” His reasoning is completely cogent as to the first point, but as to the second it suffers from the absence of any definition of the word “mental.” He relies, in fact, upon the received view that everything must be either material or mental, and that nothing is both.”

“I come now to Berkeley’s empirical arguments. To begin with, it is a sign of weakness to combine empirical and logical arguments, for the latter, if valid, make the former superfluous. [Footnote: E.g., "I was not drunk last night. I had only had two glasses; besides, it is well known that I am a teetotaller."] If I am contending that a square cannot be round, I shall not appeal to the fact that no Square in any known city is round. But as we have rejected the logical arguments, it becomes necessary to consider the empirical arguments on their merits.”

“Berkeley, as we have seen, thinks that there are logical reasons proving that only minds and mental events can exist. This view, on other grounds, is also held by Hegel and his followers. I believe this to be a complete mistake. Such a statement as “there was a time before life existed on this planet,” whether true or false, cannot be condemned on grounds of logic, any more than “there are multiplication sums which no one will have ever worked out.” To be observed, or to be a percept, is merely to have effects of certain kinds, and there is no logical reason why all events should have effects of these kinds.”

“Schematically, the argument is as follows. Berkeley says: “Sensible objects must be sensible. A is a sensible object. Therefore A must be sensible.” But if “must” indicates logical necessity, the argument is only valid if A must be a sensible object. The argument does not prove that, from the properties of A other than its being sensible, it can be deduced that A is sensible. It does not prove, for example, that colours intrinsically indistinguishable from those that we see may not exist unseen. We may believe on physiological grounds that this does not occur, but such grounds are empirical; so far as logic is concerned, there is no reason why there should not be colours where there is no eye or brain.”

“George Berkeley … is important in philosophy through his denial of the existence of matter—a denial which he supported by a number of ingenious arguments. He maintained that material objects only exist through being perceived. To the objection that, in that case, a tree, for instance, would cease to exist if no one was looking at it, he replied that God always perceives everything; if there were no God, what we take to be material objects would have a jerky life, suddenly leaping into being when we look at them; but as it is, owing to God’s perceptions, trees and rocks and stones have an existence as continuous as common sense supposes. This is, in his opinion, a weighty argument for the existence of God.”

“Berkeley discusses the view that we must distinguish the act of perceiving from the object perceived, and that the former is mental while the latter is not. His argument against this view is obscure, and necessarily so, since, for one who believes in mental substance, as Berkeley does, there is no valid means of refuting it. He says: “That any immediate object of the senses should exist in an unthinking substance, or exterior to all minds, is in itself an evident contradiction.” There is here a fallacy, analogous to the following: “It is impossible for a nephew to exist without an uncle; now Mr. A is a nephew; therefore it is logically necessary for Mr. A to have an uncle.” It is, of course, logically necessary given that Mr. A is a nephew, but not from anything to be discovered by analysis of Mr. A. So, if something is an object of the senses, some mind is concerned with it; but it does not follow that the same thing could not have existed without being an object of the senses.”