Reasons, identity, and future people › The non-identity problem

Part Four considers choices that affect which future people exist. If a decision changes when someone is conceived, it may result in a different person. In such a case, comparing two policies can mean comparing futures with different people, rather than better and worse lives for a single fixed group.

Parfit's example of a fourteen-year-old concerns a child given a bad start because the mother is so young. If she had waited, she would have had a different child with a better start. The actual child's life is stipulated to be worth living. The example should not be retold as though its defining premise were a known congenital condition; that changes the case.

If we criticize the earlier choice, we cannot straightforwardly explain the criticism by saying that waiting would have made this particular child better off. On the stipulation, that child would not have existed. This exposes a limitation in a simple comparative account of harm. It does not establish that the choice is permissible, or that every broader use of the word harm must fail.

The problem can also arise in choices about resources that alter the course of future lives. One policy may lead to worse living conditions but also to different people being conceived. Saying that those people would have had better lives under the alternative can then be false. We need a justification for preferring the better future that recognizes the change in identity.

The challenge is sharper than a general reminder to care about future generations. We may already agree that future people count. What remains unsettled is how to evaluate a choice that seems objectionable although it is worse for no particular person in the simple comparative sense. Reductionism about identity across one life does not dissolve that comparison between different possible people.