Estudio de los sensores y equipo utilizado

31 “W e are naturally inclined to believe that that our identity is always determ in ate... this natural belief cannot be true.” ibid, p217

connected with mental states, the result would be that A and B had swapped psychologies. The effect of this swapping would be the same as that of a brain swap, without the messy surgery. A supporter of the psychological view of personal identity would use this to support the claim that A was now B and vice- versa. This is because, if we were to imagine ourselves as either A or B before the operation, and we were asked to choose which person would be given a lot of money as opposed to being tortured after the operation, we would choose the person who would wake up with our psychologies. To show that this is right, we can imagine that the person who wakes up in B’s body would think to themselves “I am A”, and would be relieved if he remembered requesting riches for B’s body and sorry if he had chosen torture.

But what now if we imagine something slightly different. We are to imagine that we require very painful surgery that cannot be performed under anaesthetic. But what the doctors suggest is that, before our operation, our brain states are read into a computer and the brain states of another person are read into the brain. Then, after the operation, our original brain states will be read back into our brains. Johnston says that:

A might reasonably retort that he is being asked to undergo a double assault. First, his brain is to be fiddled with in a fairly drastic way so as to produce radical psychological discontinuity, and then he is to be caused to feel severe pain. And this reaction is in accord with the intuition most of us would have about the case.32

But, of course, this situation should provoke the same intuition as the original case. For in both of them, according to the psychological criteria theorist, there is no psychological continuity between the original person and the person who, in the same body, is to suffer severe pain. But in fact, the second story wrings out the intuition that our bodily continuity does matter.

What Johnston claims this shows is that, if it is so easy to show how

ostensibly the same case can wring out totally different intuitions, then how can intuitions be of any use here? As he puts is:

How can intuitions be reliable if we can be got to react so differently to the very same case?33

The cases are not literally “the very same", but in both cases brain states are copied and wiped from the brain of the human being before that human being is tortured. At this point we should disentangle two different points in Johnston’s critique. Firstly, there is the local objection that in these cases of exchanges of psychology, intuitions are of little use because, depending on how we tell the story, we can wring out conflicting intuitions. Secondly, this specific case should cast doubt on the general validity of trusting our intuitions. To corrupt Descartes: Johnston has found that intuitions deceive, and it is prudent never to trust completely those who have deceived us even once. It may well appear that Johnston only needs to establish his first, specific point to make his objection stick. But this is not the case. The fact that intuitions can conflict in a puzzle case leaves us with three possibilities. Firstly, it could be that the puzzle case itself is unsuitable and should be set aside. But unless we reject the use of thought experiments in general, it cannot be right to declare any particular thought experiment unsuitable just because our initial intuitions about it conflict. Given that Johnston does not critique thought experiments in general and given our considerations in section 1 of this chapter, we can set this possibility aside. That leaves two possible courses of action. Either we find some way of deciding which of our intuitive reactions is correct by probing them further, or we attempt to solve the problem without the use of our intuitions at all.

It is clear from Parfit’s comments about the very counter intuitiveness of his position that he would go for the first of these courses of action. That intuitions conflict is not the end of the story as there is more to the method of cases than brute intuitions. Nobody who uses the method of cases would want to claim that

intuitions were infallible. In a case where intuitions were in conflict, the task would then be to see which of the intuitions has to be eliminated. There are various ways of doing this. If it is the case that the view supported by either of the intuitions is incoherent or contradictory in some way, then that would provide an excellent reason for claiming that one story succeeds in eliciting a misconceived intuition. We could also place the particular thought experiment within the context of other thought experiments and arguments. If it is the case that other thought experiments support one intuition rather than the other, then this would suggest which of the intuitions is more suspect. We could then try to see if either of the intuitions rests on a mistaken belief or a trick of the mind in much the same way as Hume tried to explain how we get the idea of causation.

How could we explain away the intuition that we would have something to fear if our brains were wiped and then that body were to be tortured? Imagine that instead of brain-wiping, the operation will be performed with a general anaesthetic, but at a time before anaesthetic was generally known about. If we explained what was going to happen to A, he may well have a lot of apprehension about what will happen to him. The state of being anaesthetised is simply so alien to him that he cannot imagine being operated on and not being conscious of it. It is hard for us to imagine, being so used to the concept of anaesthesia, just how possible it would be for someone unfamiliar with it to have the terrible intuition that they will not be able to operated on without feeling pain. They too may feel as if they were gong to be subjected to a “double assault”34 of anaesthesia and being cut open. It is open for the supporter of the psychological criteria of personal identity to explain our intuitions about the second case in a similar way, and to argue that, if we were familiar with brain- wiping technology, we would not react to an impending operation undertaken in this way as a “double-assault”. Familiarity would make it as innocuous as an operation under anaesthetic.

Another way of explaining away the intuition would be to appeal to Nozick’s idea of the closest continuerss . Nozick has put forward a theory of personal identity that claims that I am identical with whatever future person is the closest continuer of me who is not a closer continuer of someone else. The inadequacies of this as an account of personal identity have been pointed out many times.36 But the view does suggest a psychological point that we will tend to view such a closest continuer as myself unless we have good reasons not to. Hence in the absence of any fully-formed beliefs about personal identity that conflict with the intuition, we will view the mind-wiped future person as ourselves. A Parfitian view may well provide the fully-formed beliefs that will explain why we actually have nothing to fear from such a process.

I need to stress that these explanations of how we come to have a wrong intuition play no part in deciding which of the intuitions is correct. We do this by examining them for consistency, both internal and in relation with other cases we consider and other intuitions we have. Only then do we do the necessary work of explaining how it is that our intuitions came up with conflicting views. This is how the reductionist should deal with cases where intuitions conflict. What Johnston needs to show is that this strategy is defective. If he doesn't, then the fact that intuitions conflict in itself cannot be an objection to the reductionist programme.

But Johnston does not deal with this head on. Instead, he offers an alternative strategy which he claims is better because it depends on intuitions less. His method has two stages, the first of which concentrates on ordinary reidentification, by which he means the way in which we identify people in actual everyday life. He then adds:

Of course it may be that a number of competing theories survive this first stage. The surviving competitors may then be evaluated in terms of their compatibility with our reactions to those puzzle cases which

35 Nozick [1981], Chapter One.