How did George Berkeley justify his disbelief in matter?

Question

I recently read Berkeley's work entitled "Three Dialogues between Hylas and Philonous" in which he gives an account very similar to that of Kant.

"Appearances, so far as they are thought as objects according to the unity of the categories, are called phenomena.... the word appearance must be recognized as already indicating a relation to something, the immediate representation of which is, indeed, sensible, but which, even apart from the constitution of our sensibility (upon which the form of our intuition is grounded), must be something in itself, that is, an object independent of sensibility. There thus results the concept of a noumenon."

-Immanuel Kant, Critique of Pure Reason

"I say in the first place, that I do not deny the existence of material substance, merely because I have no notion of it, but because the notion of it is inconsistent, or in other words, because it is repugnent that there should be a notion of it. Many things, for aught I know, may exist, whereof neither I nor any other man hath or can have any idea or notion whatsoever. But then those things must be possible, that is, nothing inconsistent must be included in their definition. I say secondly, that although we believe things to exist which we do not perceive; yet we may not believe that any particular thing exists, without some reason for such belief: but I have no reason for believing the existence of matter."

-George Berkeley, Three Dialogues between Hylas and Philonous

He continues from this point, but I find little evidence besides his own justifications, which seem to be severely lacking. " Many things, for aught I know, may exist, whereof neither I nor any other man hath or can have any idea or notion whatsoever." would seem like a statement relating to the Kantian idea of noumena (and so I shall reference it as such). If he believes in noumena why does he find reason to justify a lack of faith in the nature of something to which he has no access or knowledge (to which he also admits, as Kant also has). Does he have other sources to better explain/justify his beliefs?

Answer 1

Berkeley gives two arguments in the quoted passage, and the first one does resonate with Kant's later arguments. But Berkeley's came before Kant's.

First, he says that the notion of matter is "inconsistent". This is roughly because it is usually defined in terms of attributes (extension, color, sound, etc.), which only make sense as perceived (by their semantic origin), and yet at the same time it is postulated as existing independently of any perception. This is not "disbelieving" in matter, which would be accepting the idea but claiming that it is false, it is rather like Russell's "set of all sets not containing themselves". It seems like we defined something, but in fact we just made a label for a description to demonstrate that the description is gibberish.

Kant later developed and extended this argument to contend that categories of experience can not be applied beyond all possible experience, and produce antinomies (arguments with contradictory conclusions) when this is attempted. This indeed leads to the idea of "thing in itself" (often conflated with the noumenon), ideal projection "demanded by reason", but to which no category applies. In other words, of it we can only say that we can say nothing, even calling it "thing" is already a transgression.

The second argument is from the principle of sufficient reason, e.g. in Spinoza's formulation "For each thing there must be assigned a cause, or reason, both for its existence and for its nonexistence." In principle, it shouldn't be needed after the first, there can hardly be a reason for belief in gibberish, let alone a sufficient one. But Berkeley perhaps wishes now to address the more practically minded. One can even interpret it as an application of Occam's razor. After all, Berkeley himself built a whole philosophy of esse est percipi (to be is to be perceived) without ever needing whatever "matter" is supposed to designate, thank you very much. But he is not opposed to inferring existence of unperceived things in principle, as long as their notion is "possible". For example, his alter ego in Dialogues, Philonus, proclaims that "from a cause, effect, operation, sign, or other circumstance, there may reasonably be inferred the existence of a thing not immediately perceived, and that it were absurd for any man to argue against the existence of that thing, from his having no direct and positive notion of it", and argues for the existence of other spirits, see Does the Denial of the External World Lead to Solipsism?

Husserl gives a variant of Berkeley's first argument in Ideas I §55 and accepts it, but insists that it does not lead to his idealism:

"An absolute reality is just as valid as a round square. Reality and world are names here precisely for certain valid unities of sense... If anyone reading our statements objects that they mean changing all the world into a subjective illusion and committing oneself to a "Berkeleyan idealism," we can only answer that he has not seized upon the sense of those statements. They take nothing away from the fully valid being of the world as the all of realities, just as nothing is taken away from the fully valid geometrical being of the square by denying that the square is round".