Abortion and the moral significance of merely possible persons

"This book has two main goals. The first is to give an account, called Variablism, of the moral significance of merely possible persons -- persons who, relative to a particular circumstance, or possible future or world, could but in fact never do exist. The second is to use Variablism to illuminate abortion. ... Variablism supports the argument that the early abortion is ordinarily permissible when it is what the woman wants. .... In contrast, the late abortion is ordinarily subject to a different analysis. For the loss incurred in that case has full moral significance, according to Variablism, since it is incurred at a world where the person who incurs it does or will exist."--P. [4] of cover.