To: Francis W.
From: Geoffrey Klempner
Subject: Berkeley: to exist is to perceive or to be perceived
Date: 31 May 2007 09:56

Dear Francis,

Thank you for your email of 24 May, with your fourth essay for the Possible World Machine, in response to the question, ''To exist is either to perceive or to be perceived.' -- How would you explain Bishop Berkeley’s idealism to someone who knew nothing about philosophy?'

I enjoyed your little dialogue, which does a good job of revealing the problems and contradictions in the way we think and talk about our sense experiences, in a way which makes Berkeley's theory seem not such a bad explanation after all.

First of all, we need to be clear about what is Berkeley's theory. As your story illustrates, there are two versions. On the first version, everything we say about 'things' in the 'world' can in principle be expressed as hypothetical statements about actual and possible experiences. To say that the cup of coffee is on my desk while I am downstairs is to say that there are true statements of the form, 'IF I were to look in through the door THEN I would see it' - and so on for every other statement. At some points, Berkeley gives the impression that this is his complete theory.

But Berkeley also has what seems to be a 'fallback' position that when no-one is perceiving the cup of coffee it is perceived by God. In that case, we don't need the reduction to hypothetical statements about experiences. Why bring in God? Peter's explanation at the end that Berkeley's idea was 'greatly influenced by his religious convictions' gives the motivation but not the underlying argument, which, a supporter of Berkeley would say, is independent of the motivation.

The underlying argument is that a hypothetical statement cannot be 'barely true'. This is a basic observation about the way we understand hypothetical statements. If I say, 'If you try to stand on that chair it will break,' the implication is that there is something about the actual structure of the chair -- the thinness of the wood, or the fact that some of the screws are missing -- in virtue of which the hypothetical statement is true.

Suppose I said, 'If I tap the table three times, it will be sunny tomorrow.' And I don't tap the table. The next day it is raining. You ask me, 'Why did you believe that if you tapped the table it would be sunny?' I say, 'The thought just came into my head.' 'OK,' you say, 'Let's forget WHY you believed it. What could make it TRUE NOW that if you had tapped the table it would have been sunny?' And I say, 'If it is true, nothing makes it true. It is just a true hypothetical fact.' -- Don't you think that there is something very fishy about that idea?

There are at least three aspects to the way we normally think about experiences which cause problems. Sometimes we make errors in the identification of objects (Peter for Tim), which shows that experiences cannot be relied on. Then there is the troubling fact that things are not always what they seem, for example the straight stick which looks bent in water. Another fact which I thought you were going to mention when you talked of the warm coffee is how different people perceive the same object as having different qualities (what is warm for David might be hot for Peter), and indeed the very same object can seem to 'change temperature' (suppose David tastes the coffee, then has a big bite of ice cream, then tastes the coffee which now seems 'hot').

Yet, along with these commonly accepted facts about experience, we also have the common sense belief that objects 'themselves' do not change. The 'real temperature' of the coffee is what it is irrespective of the impression that it makes on us. The question is, how are you going to make someone begin to doubt that common sense view?

Berkeley would say the idea that there is some difference between experiences and 'objects themselves' or 'matter' is a myth. No-one has ever seen, touched or tasted an 'object itself'. All we ever experience are experiences. So why this persistent belief that 'material objects' are 'out there'?

You give the example of eating a sandwich. What is my interest in this sandwich? I know that if I eat it, my hunger will be satisfied. To me, all the sandwich IS is a particular kind of experience (smelling, tasting, chewing, swallowing) which I believe will be followed by other experiences (my hunger being satisfied, feeling more energy to work). The suggestion is that Berkeley would generalize from this example by pointing out that if all of my experiences, now and forever more would be just as they are even if 'material objects' or 'objects themselves' were taken away, then the idea of an 'object itself' is completely empty pointless, 'a wheel that turns, although nothing else turns with it,' as Wittgenstein would say.

But what about causes? You raise this question too. Investigating causes is something that we do. The coffee is not warm enough. David investigates the cause and discovers that the lazy waiter allowed it to stand in the serving hatch for several minutes before bringing it over to your table. Or the coffee tastes bad, and David discovers that he mistakenly put in salt instead of sugar.

But that leaves the question of the ultimate cause. Why is there experience at all? Could it be that experience is all there is, with nothing 'out there', nothing 'causing' it? I have already given a possible reason why we resist that idea -- because that would require 'translating' statements about objects into hypothetical statements about experiences, and hypothetical statements cannot be 'barely true'.

All the best,

Geoffrey