From the title of Ricoeur [1991].

diachronic mental life should actually be described. However, having made these alterations, we can see several other advantages the I* relation has over Relation R. In general, the I* relation explains better why it is that certain hypothetical cases are importantly different from cases of normal survival. In this section I explain why it is that the I* relation is a less liberal principle than Relation R, and why that illiberality should be welcomed.

Firstly, we should consider fission. Rovane 15 has pointed out how fission undermines some of the most basic features of our lives. Consider intentions. Though it seems possible for someone who knows that they are going to split to formulate intentions for each of the two fission products to fulfil, these intentions could not function like our normal ones. Firstly, our intentions assume that we will not split as they assume only one person will be there to carry them out. In certain cases, such as intending to be the first person to do something, it

requires that only one person be there. Secondly, and more seriously, the way in which we fulfil our intentions in a fission situation would differ quite fundamentally from the way we fulfil normal intentions. For example, normally, if I intend to write a novel, in order to fulfil that intention it is enough that the intention continue and I act upon it. But if I know I am going to split, I may decide to form the quasi-intention that only one of my fission products write that novel and that the other travel the world. In this case, acting upon the continued intention is not enough to fulfil it. This is because both fission products will wake up with exactly the same desires and wishes as the pre-fission person. It will then be necessary for them to work out, or decide, which of them should fulfil which part of the intention. It may be that the decision made was that the person who woke up on the left hand side of the other would write the novel and the person on the other side travel the Earth. Maybe a coin was to be tossed. But whatever the decision, the fission products will not know what was quasi­ intended for them until they either toss the coin or see which side they are on.

But no such procedure is required with normal intentions. The fact that the intention is remembered and continued is enough.

Parfit’s Relation R does not account for this difference, as it doesn’t explain what sort of connection must hold between an intention and a later action. However, the I* relation does. I maintain that the intention must be causally efficacious, in the same way as ordinary intentions are causally efficacious, if two persons are to be fully I* related and thus be part of a fully unified mental life. In the fission case, this condition is not met, as Rovane explains. What this means is that in the case of fission, there is rather less mental continuity than there is in normal cases, because there is rather less functional indexicallty. This is one reason to suppose that fission is not like ordinary survival. Now, the importance of this difference is another matter. Even in ordinary survival, there can less continuity than is normal. An amnesiac, for example, may need to make notes for themselves to carry out their own intentions, for example. This does not mean that the amnesiac cannot enjoy a unified mental life, but it does mean that it is not as unified a mental life as is normally the case. In my opinion, the same is true in fission. We have rather less mental continuity than is normal, but enough for us to say that there is a unified mental life connecting the pre and post fission persons. One reason for holding this is that there would still be a very clear internal narrative for both fission products. But however important we decide the difference is, there is a difference, and my account acknowledges this difference in a way in which Parfit’s does not.

These considerations also bring out the point that all parts of the I* relation can hold to a lesser or greater degree. Neither functional indexicallty nor direct psychological connectedness is an all or nothing relation. Consequently, the degree to which the internal narrative of our lives coheres can vary.

A second reason for favouring an account of the kind I have suggested is that, taking as it does its standards from normal cases of survival, it corresponds

more closely with what we believe about real people. 16 The kinds of relations

required for there to be an unified mental life that links two numerically distinct persons are the same as those required for a unified mental life in a single person. And the borderline cases in such cross-person cases are just like borderline single-person ones. For example, as discussed above, we may doubt that a severe amnesiac has a unified mental life, just as we can doubt if two people who are not completely I* related have a unified mental life. But the tests which we apply to try to answer those questions are the same. Does the amnesiac/later person remember earlier experiences as their own? Are the intentions of the amnesiac/earlier person causally efficacious as regards the actions of the amnesiac/later person? Is there a coherent internal narrative that allows the amnesiac/ later person to make sense of the past? Of course, sometimes these questions will have indeterminate or uncertain answers. But the uncertainty is the same in both cases. The borderline cases in our imagined examples are just like the borderline cases in ordinary, pathological cases.

A third aspect of mental continuity which Parfit’s account neglects is the need for both backward and forward looking connections. 17 Consider q-memory once more. If Jane q-remembers John's experiences. Parfit says Jane is phenomenologically connected to him. Relation R is simply a product of enough of these kinds of connections. I would not deny that under such circumstances Jane is psychologically connected with John, but no number of such similar connections could ever lead to the kind of psychological continuity Relation R should demand. The reason for this is that Jane will only be retrospectively connected with John. Her memories look back at John’s experiences. But John never looks forward to Jane’s future. He doesn’t plan what Jane will do, nor does he anticipate having Jane’s experiences. His plans, beliefs and desires will not effect Jane. This is different to the teletransportation case. Here, there is

16 Wilkes [1993] has made the strongest case for the view that our accounts of persons must correspond to what actually is the case.