There has been a bit of a debate between myself and Lord Keynes over at his blog. Most of the relevant debate can be found in the following blog and in the comments of this blog. In response to my comments Lord Keynes has done another post that is quite long. Frankly, I don’t think that many of the complaints he raises against Berkeley’s arguments are nearly as problematic as the dogmatism and mysticism at the heart of his own doctrine. For that reason I will only deal with the kernel of the issue here.
The most important point that Lord Keynes raises is the following,
Epistemologically speaking, the idealist – unless he can provide a valid and sound deductive argument or arguments – must use inductive arguments on the basis of indirect evidence to prove his hypothesis of a god or “super-mind.”
But that means, epistemologically speaking, that the idealist and the realist are also on the same ground, since the indirect realist’s belief in an external world is also an inductive inference on the basis of indirect evidence.
So again in this respect the idealist position is not epistemologically superior to the realist one, but on a par.
I have tried to deal with this a number of times in the comments but I suppose I can repeat myself if I have not bee sufficiently clear.
The question here boils down to this: which is a more robust argument for the constancy of ideas, matter or a ‘super-mind’? Berkeley contends that the word ‘matter’ is a word without content. If I try to describe what matter is I will never be able to do so. For example, I may say that matter is hard; but then Berkeley would say “no, the hardness is a perception, it is an idea”. Or I may say that matter is extended; to which Berkeley would reply “no, extendedness is only an idea”.
Eventually when you boil it right down the only thing we can say about matter is something like “matter is the cause that underlies the constancy of our perceptions”. But this is a tautology. If matter is being used to explain the constancy of our perceptions and is at the same time defined in such a way as to be the cause that underlies the constancy of our perceptions then it is clearly a tautology. The word ‘matter’ thus means nothing. It is an empty, self-referential term. A signifier with no signified.
Now, the ‘super-mind’ argument is different. I can reason by analogy using the super-mind argument. I can examine what constitutes the entire world that I know — that is, the world of ideas and minds — and I can divide the ideas into two groups: (1) ideas over which I have control (imaginations etc.) and (2) ideas over which I have no control (perceptions). If I allow that these, together with my mind, are the two base constituents of the world I experience I can then use my logical capacity to try to explain the ideas that fall into category (2) with reference to those that fall into category (1).
So, I can say that since all that I experience are ideas and minds then all that must exist are ideas and minds — this is an empiricist position. Now, I can posit that since there are ideas that my mind does not have control over — that is, ideas that fall into category (2) — then some other mind must have control over them. Thus we posit a super-mind that brings these ideas into being.
The differences between the materialist and the idealist position is that the materialist position relies on a tautology (the empty term ‘matter’) to explain the constancy of our ideas. This empty word has no content. Matter is never experienced and so it can never be explained. Thus materialism is anti-empiricist — it requires dogmatic or mystical foundations. But the idealist position is purely empirical. It uses the information we gain through induction and combines it with logical reasoning to explain the constitution of the world. There are no mysterious or dogmatic terms in idealism. The super-mind is formed through a combination of induction and logical reasoning.
This is why idealism is a superior philosophy. That is, unless one’s temperament is inclined toward dogmatic or mystical doctrines in which case materialism is obviously more preferable.
I do not see any of the problems Lord Keynes raises about Berkeley’s philosophy particularly compelling — for example, he asks why not many super-minds rather than one? I would answer: sure, if you believe in parallel universes! — but even if they are the central question remains: is empiricism preferable to mysticism? If so, then Berkeley’s philosophy is preferable to materialism. But if you wish to keep certain ‘mysteries’ of the metaphysical structure of the world intact — perhaps to give a sense of awe to what you see as a scientific Doctrine of Truth — then what makes your philosophy any better than a religion?
After all, the mystery of matter is no different to a mystery of faith — because what is at issue here is faith; faith in matter. For, as the Wiki article on Mysteries of Faith says,
In theology, an article of faith or doctrine which defies man’s ability to grasp it fully, something that transcends reason, is called “a mystery of the faith”.
Read in that light materialism is a theological doctrine that reflects on a mystery called ‘matter’.
Fixing the Economists 
Sorry, this is a silly comment, but because I’m Greek it somehow leaps to the eye: the Greek for the “Mystery of faith” is completely wrong, the two last words are in the wrong gender (faith is female in Greek). Also, unlike Latin, Greek (both ancient and modern) has an article. So, it should look like this: Τό μυστήριον της πίστεως (I hope this shows up in Greek letters as intended).
Haha! Sorry. I just pulled the image from Google. I don’t speak Greek. Hopefully I don’t have too many Greek readers!
Philosophical layman here. If I may misquote you:
If the super-mind is being used to explain the constancy of our perceptions and is at the same time defined in such a way as to be the cause that underlies the constancy of our perceptions then it is clearly a tautology. The word ‘super-mind’ thus means nothing.
The super-mind is never experienced and so it can never be explained.
To my mind (pardon the pun), only a position that does not posit the existence of a super structure beyond the individual mind is consistent in the sense above. But then the ‘explanation’ of constancy goes down the drain.
It is the experience of constancy that triggers the leap of faith to an external truth that lies beyond anyone’s individual mind. It is then a matter of semantics whether this ‘truth’ is called matter or super-mind. Both are are dualist positions.
Wiki writes:
Idealism thus rejects physicalist and dualist theories that fail to ascribe priority to the mind.
Priority of the mind, not super-mind vs. matter, is the operative term that both sides should be agreeing on in this case, no?
There is a big difference.
“Matter” is a term that is empty. It has no meaning.
“Super-mind” is a term that has meaning. It is based on logic and induction.
The outside truth is a vessel whose content remains mystical by definition. We can fill it in our minds with ideas or concepts derived from our own experience,which includes the term super-mind or concepts of physics or maths or remain agnostic about its contents, but none of these supposed fillings can ever be known to be the outside truth itself. The fact that the term ‘mind’ has a meaning to us because that’s all we have to work with and supercedes all products of our minds, including say physics, does not make it the true content of the mystical vessel. It is the humility of knowing that one can never know with certainty that should be the common ground here.
That’s a mystical position. I don’t like mysticism. I make my judgement based on induction and logic and that leads me to say that a super-mind is a more coherent explanation. Is it definitely true? No. But it is the most likely to be true given the evidence.
But then how on earth did Berkeley came to his conclusions about idealism? Obviously by not interacting with the world like we everyday people do…He supposes that we live in the world just like he does–by armchair theorising. But surely the everyday person doesn’t do that. Thus his arguments are only satisfying for people who do a similar kind of armchair theorising that he did. His reasoning is a kind of Scholastic philosophy which unfortunately still exists in economics departments worldwide.
Mysticism is a non-empirical matter, so frankly I don’t mind calling “materialism” a kind of mysticism. But then we wouldn’t need such philosophical arguments, then. That sort-of defeats the purpose of making them. It’s like trying to convince a true believer in Christianity that their beliefs are wrong. For me, once someone says “It’s mystical”, then we’re no longer having a philosophical discussion…but playing by a different kind of language game, a la Wittgenstein.
Incoherent.
(Sticks tongue out)