To: Richard G.
From: Geoffrey Klempner
Subject: Difference between a solipsist and a psychopath
Date: 25 May 2007 13:04

Dear Rich,

Thank you for your email of 19 May, with your second essay for the Moral Philosophy program, in response to the question, ''A psychopath is a solipsist who puts his metaphysical beliefs into practice.' - Is it possible to be consistently a solipsist in theory but ethical in practice? What would that mean?'

This is the best piece of work you have done for me, in terms of the careful and systematic way in which you build up your argument.

However, we don't understand the term 'solipsist' in the same way. This has some importance for the understanding of the question.

A case can be made (although I will consider some doubts in a moment) that your solipsist believes in a version of mind-body dualism, or at least rejects materialism (whatever view one wants to put in its place). Thus, David Chalmers (interviewed in Philosophy Pathways a couple of issues ago) uses the zombie hypothesis as an argument against materialism which goes as follows: I can conceive of the possibility that there could be an entity physically like me in every respect, but which did not have consciousness. Therefore, consciousness cannot be something physical, even if it arises as the result of physical processes.

On this view, while we would normally expect that the same kind of process produces the same result (if my brain produces consciousness in me then it seems reasonable to infer that it produces consciousness in you) this is not guaranteed. I hope hat you are not a zombie and that the other persons I meet are not zombies but I can never be 100 per cent sure. All I know is that I am not a zombie.

Before I consider my doubts about this interpretation, let me first explain how I understand 'solipsism'.

My solipsist is much more extreme. Everything that 'exists' is merely a logical construct based on my experience. 'Table' or 'mountain' are just words which refer to recurring groups of sense impressions. Apart from my experience, there is nothing. In fact (as Kant effectively showed) this kind of solipsism is difficult to state without contradicting oneself, because the only coherent way to describe experience is using concepts which apply to a world of 'objects' in 'space'. However, taking Kant's criticisms on board, one may talk of a 'transcendental solipsism' according to which all that exists is a collection of uninterpreted data together with a 'power of judgement' which collects the data into recognizable packages, tables, mountains, people. On this view, other people are merely characters in the story of my world. The question whether these characters are zombies or non-zombies cannot even arise.

This leads to the question tackled in the program whether this kind of solipsism could form the basis of an ethical theory. But we do not need to consider that now because you have chosen to go in a different direction and I want to go along with you just to see where this might take us.

I said I wasn't sure about the dualist interpretation of your version of solipsism. That is because you also seem to hold that states of consciousness, if they exist at time T, must be experienced by ME at time T. In your terms, 'Life is only caused by my body.' In defence of this view, one might argue that I just don't comprehend (no-one comprehends) how any 'life' can be 'caused' at this moment which is not part of my life. It could be argued that this is the conclusion that the mind-body dualist is driven to, as a result of an inevitable process of scepticism.

In that case, the only way 'life' can be 'caused' by the bodies of other persons is if at some point in time other than the present, I have inhabited or will inhabit those bodies.

Thus, I will be kind to the old tramp, because one day I might be looking out on the world from the tramp's eyes.

In this essay, you take this line further by considering the difference between the thought that I will be the tramp and the thought that I once was that tramp. If I was the tramp in the past, then, rationally, I have no basis for compassion because there are no 'desire satisfactions' to look forward to.

Of course, it is also part of the theory (as I understand it) that it is impossible to tell whether I will be the tramp or whether I was the tramp. In a situation of uncertainty, I must act as if I will be the tramp. So one gets the same ethical result as before, regardless of the question of the difference between 'was' and 'will be'.

A further development is your consideration of the reason why one would care about the 'desire satisfaction' of 'eternal zombies'. Here, I was a bit confused. Your argument seemed to depend on the idea that, even if I don't care about the effects of my actions on eternal zombies, some person might care, and since I might find myself inhabiting the body of that person in the future, I have to take that person's feelings into account too.

This argument, if valid, would also apply to people with very weird beliefs. Last night I saw the film 'Notting Hill' on TV. At a dinner party, a young woman confesses to being a 'fruitarian'. Fruitarians believe that plucking a 'live' tomato from a tomato plant, cooking it and eating it is 'murder'. Only fruit and veg which have 'fallen from the bush' may be eaten. This is probably a scriptwriter's joke, but if there is any possibility that in the future you will own the body of a fruitarian, then you 'ethically' ought not to eat tomatoes plucked form the bush.

You also make an attempt to render convincing the idea that we might somehow have reasons to 'care' about the states of eternal zombies, giving the example of a comedian. However, a joke is a joke, whether you hear a comedian telling it or whether you read it in a book. If a computer could be programmed to make jokes, then our laughter would not be affected by the knowledge of where the joke came from.

Suppose Fred is lonely, and a Genie from the bottle gives him beautiful girlfriend to keep him company. The only drawback is that the Genie tells him that she is an eternal zombie. Should Fred care? He can have great times with his new playmate. A philosopher would object that the act of love predicated, if not on the belief in the reality of the other person, then on the fantasy of being in a relationship with a real person. In that case, enjoying the company of a zombie girlfriend is no different, in principle, from playing with a giant blow-up doll.

All the best,

Geoffrey