Berkeley on Scepticism

 

At the beginning of the Third Dialogue responding to Hylas’s worries that in Berkeley’s philosophy there is no chance we can know the real nature of things because we can know only appearances and so scepticism seems inevitable, Berkeley says:

 

“….and is it not evident you are led into all these extravagancies by the belief of material substance? These make you dream of those unknown natures in everything. It is this occasions your distinguishing between the reality and sensible appearances of things.”

 

And further he says:

 

“That a thing should be really perceived by my senses and at the same time not really exist, is to me a plain contradiction; since I cannot prescind or abstract, even in thought, the existence of a sensible thing from its being perceived. Wood, stones, fire, water, flesh, iron and the like things I name and discourse of, are things I know. And I should not have known them, but that I perceived them by my senses; and things perceived by the senses are immediately perceived; when therefore they are actually perceived, there can be no doubt of their existence. Away then with all that scepticism, all those ridiculous philosophical doubts……I might as well doubt my own being, as of the being of those things I actually see and feel.”

 

Further again Hylas expresses a doubt, if you ceased to exist then “cannot you conceive it possible that things perceivable by sense may still exist?” and Philonous responds by saying, “when I deny sensible things in existence out of the mind, I do not mean my mind in particular, but all mind.” These other minds he points out have an existence exterior to his mind and so there must be some other mind wherein they exist, which is God’s Mind.

 

From these passages we learn: a) scepticism arises because we assume there is a distinction between appearance and reality, b) this assumption depends on assuming that a material substance exists which is the real nature of things, but c) what our senses tell is the real nature of things, there is nothing more to know since to exist is to be perceived. Note that in these passages Berkeley is going after the stronger conclusion, there is nothing else to know except what the senses reveal. He is implicitly denying here the very possibility of a material substance or a third nature and basing his argument against scepticism on the presumption that they are possible because without getting rid of this possibility he can never eliminate the doubt that there is more to know about than what simply appears to the senses. One can probably come up with weaker readings of these passages, but they won’t do justice to the Berkeley’s confidence that nothing ‘unknown’ remains to be known in order to have knowledge contra scepticism.

 

Descartes uses a 2-way separability test to prove a real distinction exists between mind and matter, invoking a 2-way separability test implies the violation of the transparency principle which says that mind knows everything what transpires within it because its nature or essence is an open book to itself but Descartes is not able to preclude the possibility that unknown to the mind matter may still belong to the mind so that mind could possibly be extended. Clearly Berkeley too subscribes to this principle and more so than Descartes because for him what is sensed or perceived has to be necessarily within the mind, so the relation between mind and Idea is a necessary one, on the strongest reading a necessity due to identity. So if we put up the question – Is it possible that sensible qualities can exist unperceived, we would get the reply “the existence of the sensible thing consists in its being perceived.” Note Berkeley moves from ‘x is perceived’ which is a fact to ‘Necessarily, if any x exists then it is perceived’, which is a stronger conclusion and he can make that transition only by showing that the existence of the object of perception cannot exclude perception at the cost of excluding its own existence. So the existence of the object of perception can necessarily include perception if there is no possible world where it can exist unperceived (and only then can we prove identity of Idea and Mind or consciousness) and so if the possibility of the existence of matter remains open, the possibility of unperceived existence of the object of perception i.e. sensible qualities remains open too because necessity excludes all possibilities; in no possible world could a square be a circle.

 

So as we saw Descartes on the one hand he needs a 2-way separability, to show that sensible qualities inhere in a mind and on the other hand to show that they cannot inhere in an unthinking substance and if he proves that, then he cannot hold onto the transparency of mind which means he cannot exclude the possibility that a sensible quality may exist in matter despite consulting his Ideas. Berkeley is in practically the same predicament, he needs to show that matter is impossible in order to validate his ess est percipi idealism – sensible qualities exist in being perceived and so no possibility of their unperceived existence arises. But how should he go about proving that esse est percipi is a necessary truth? The testimony of consciousness is insufficient to determine what the esse of sensible qualities is and so from ‘x is perceived’ he cannot prove ‘existence of x consists in being perceived’ merely from the testimony of consciousness (i.e. from his version of transparency principle) without excluding certain possibilities or the possibility that a material substance exists. Like Descartes he would ideally want to prove from the testimony of consciousness that the existence of sensible qualities necessarily imply the mind but like Descartes he feels the need to demonstrate the impossibility of any alternative scenarios and hence adduce additional proof of the impossibility of matter. The moral of the story is that the testimony of consciousness is insufficient to establish the ontological status of the objects of consciousness.   

 

This conclusion will be clear in context of Waxman’s interpretation in his book 'Kant and the Empiricists'. Waxman believes that Berkeley subscribes to a psychological idealism which need not assert that a third unknown nature cannot exist, only that it will be inconceivable. Following his exegesis we can say that the reason Berkeley excluded the possibility of the existence of sensible qualities within unthinking substance was because the scope of possibilities was limited by Berkeley in accordance with possibility of perception and so an unthinking substance cannot be conceived or thought but from this we cannot derive the ontological conclusion that such a substance cannot exist, however Waxman believes Berkeley did not want to go that far and hence the idealism Waxman attributed to Berkeley was psychological idealism and not ontological idealism. But in order for psychologism about the concept of existence to go through, there should be no possibility left of an unperceived existence. Berkeley like Locke does not distinguish between Idea and actual thoughts and these actual thoughts essentially constitute the concept of existence because they are responsible for the content the concept has. And so a successful psychological explication of the concept of existence must exhaust all possibilities and the possibility of an unperceived existence must be denied. This leads to ontological idealism rather than a mere psychological one. But if the possibility of unperceived existence is leftover then psychologism about the concept is also proved wrong since the concept has a certain content or certain possibilities that are not exhausted by actual thoughts.

 

Berkeley does clearly want to restrict the limits of thought to the limits of sense and to this end he has to show that the content of thought essentially refers back to sense, this is where his nominalism comes in. The challenge is to distinguish between the psychological conditions of the acquisition of a concept from the sensible origins of the content of the concept itself. It is the latter that Berkeley is after. Waxman correctly believes that at the heart of this issue is the separability principle which he takes to lead to the esse is percipi conclusion. But Waxman construes the use of the principle as a psychological principle and not an ontological principle and the resulting idealism too therefore is a psychological one. I think where he is wrong is in holding that Berkeley is not after the stronger conclusion – an ontological idealism and if the impossibility of matter remains to be proved then even the psychologistic conclusion is under threat. The reason is simple, SP says that we cannot conceive an x without y because they cannot be perceived asunder, sensible objects cannot be conceived without Ideas and Ideas without consciousness. From this the conclusion that would follow is – the psychological conditions for thinking one kind of thought depends on another. Clearly Berkeley cannot use this principle to show that sensible qualities cannot reside within an unthinking substance. His argument is based on showing that the essence of Ideas involves the mind and so if we take away one, we take away another. This is how he means to use the SP, as an ontological principle, not just a psychological principle and the psychologistic conclusion itself depends on this stronger ontological reading that the Idea cannot exist without the Mind, even the possibility does not arise. Berkeley strives for the stronger ontological idealism but he cannot get there because hidden within his paradoxes is an ambivalence in the use of the term ‘matter’, on the one hand it means ‘repository of sensible qualities’ and on the other ‘unthinking substance’. The challenge before him is to show that it is impossible that sensible qualities can exist unperceived. On the one hand he argues that we cannot conceive the existence of sensible qualities in insensible substances, but like Descartes it troubles him why someone cannot say that unknown to him, sensible qualities do exist unperceived in matter. The testimony of consciousness is restricted to the presence of sensible qualities within consciousness, from this he cannot derive conclusions about the possibility of existence of sensible qualities somewhere outside the mind. So now he is in a predicament, the testimony of consciousness fails him, the conceivability test fails him because the existence of matter is not precluded and so finally he comes to demonstrating the impossibility of matter on grounds that its very conception involves a ‘manifest repugnancy’, which repugnancy lies in inherence of sensible qualities in an unthinking substance but not in the unthinking substance itself. Even if it is admitted that we have no Idea of an unthinking substance, we cannot move to the stronger conclusion that such a ‘third nature’ cannot exist and till such a nature is possible, the existence of sensible qualities unperceived is possible because Berkeley has given no grounds what so ever to preclude this possibility.