Is acrasia possible? Can you do wrong knowingly? Opinion divides. Each, to the other side, is a paradox monger.

At issue is the most felicitous set of concepts and principles to bring to descriptions and evaluations of human action. So to speak, such a set is an outline of a script for reality to play: it provides identities and relations in which individuals and events or whatever may be cast. Deniers typically begin with a set that rules acrasia out of court, recasting alleged examples in a different explanatory mold. Affirmers typically begin with plausible examples and look for a theoretical framework to place them in, taking those that disallow it to be absurd. But any denier, on legitimate dialectical grounds, can point out that such a reductio is a petitio. So it is a resilient issue, still with us after being bounced around so much in history.

The abortion debate rages on. Yet the two most popular positions seem to be clearly mistaken. Conservatives maintain that a human life begins at conception and that therefore abortion must be wrong because it is murder. But not all killings of humans are murders. Most notably, self defense may justify even the killing of an innocent person.

Liberals, on the other hand, are just as mistaken in their argument that since a fetus does not become a person until birth, a woman may do whatever she pleases in and to her own body. First, you cannot do as you please with your own body if it affects other people adversely. Second, if a fetus is not a person, that does not imply that you can do to it anything you wish. Animals, for example, are not persons, yet to kill or torture them for no reason at all is wrong.

In a recent trial in the United States a physician was convicted of manslaughter during the performance of a hysterotomy on a woman pregnant from twenty to twenty eight weeks. Some members of the jury, in their deliberations, were much impressed by seeing a photograph of a fetus of about the same age. The experience apparently provided some jurors with reason to conclude that the fetus which did die during or immediately after the hysterotomy was a human being or a person or, at least, was so like a child that the killing of it was prohibited by the law of homicide. If being a human being is not the same as being a pre-natal progeny of homo sapiens, it is difficult to understand how one could “tell by looking” whether the fetus is a human being. But the sight of a fetus of twenty weeks or longer does, I think, tempt us to think that from a moral standpoint we ought to extend the same treatment to such fetuses, or virtually the same, as we extend to newborn babies and young children. The visual similarities between middle or late stage fetuses and newborn babies is striking.

The doctrine of double effect (hereafter abbreviated to DDE) is a principle of conduct that allows its adherents in certain difficult cases, provided certain conditions are satisfied, to bring about an effect indirectly that they are forbidden to bring about directly. By ‘indirectly', I mean that the effect in question is aimed at neither as an end in itself nor as a means to an end. In terms of Bentham's distinction between ‘oblique’ and ‘direct’ intention, DDE may be characterized as the thesis that, in certain difficult cases, provided certain conditions are satisfied, one may bring about (it is permissible to bring about) by oblique intention, as the merely foreseen consequence of an act, what one may not directly intend, either as end or as means.

The conditions in question are four, and failure to satisfy any one of them ensures the inapplicability of DDE to a particular situation. The first condition is that the act to be done, considered in itself and apart from its consequences, must not be intrinsically wrong.