Abstract

The subject of this dissertation is fetal ontology, not the morality of abortion. I try to show that zygotes are not human beings. ;Unlike many philosophers, I am unwilling to give 'human being' to the biologists. It should not be confused with 'Homo sapiens' or any other taxonomic term of biology. On the other hand, it should not be confused with 'person' either. ;I investigate a number of attempts to fix the point at which we first become human beings. None of them, I try to show, support the conclusion that zygotes are human beings. The strongest argument for the humanity of the zygote, I believe, derives its conclusion from the premisses that we are essentially human beings and that we were once zygotes. While I mention some reasons for thinking that the first of its premisses may not be true, I am mainly occupied in challenging the second. I formulate and defend the idea that we come into existence gradually . At the time "our" zygotes existed, we did not fully exist. So either "our" zygotes did not fully exist then either, or else we were not then plainly identical with them. In the latter case either we were "indeterminately" identical with them or we were not identical with them at all . In any case we were once zygotes at best only to the extent that we then existed--i.e., hardly at all. ;The most likely view concerning our beginnings is that we both come into existence and come to be human beings gradually, during a period which corresponds at least roughly with our gestation