Elizabeth Anscombe, answered from the texts and cited to the page.
Moral absolutism, as I defend it, is the position that certain kinds of action are forbidden regardless of consequences — forbidden in advance of any particular case, not merely presumptively forbidden subject to override when the stakes are high enough. The clearest instance is the intentional killing of the innocent. Whenever rulers, soldiers, terrorists, or other violent men deliberately kill innocent victims, what they do is murder — and no advantage to be got by the killing counts as exoneration.1
If someone maintains that such advantage can justify the killing, then what is thereby justified is murder itself; the definition has not been escaped, only the word avoided.2 Now the absolutism requires some care in its application, because not every killing is murder, and not every action that leads to death is forbidden. Intentional killing in warfare, by police fighting violent criminals, or by execution of a lawful sentence — these can be murderous, but they are not necessarily so.3
The description "intentional killing of one human being by another" does not by itself settle the moral quality of the deed; what settles it is whether the killing is private — that is, not an action belonging to the exercise of civil authority — and whether it is intentional.4 Furthermore, murder is not confined to cases where there was a strict intention to kill.
The arsonist who burns down a house not caring whether people are inside is as much a murderer if they die as if he had aimed at their deaths; his action falls within the penumbra surrounding the hard core of the concept.5 There is also the problem of foreseen but unintended deaths. One cannot say that no action may be done which foreseeably leads to someone's death — at that rate, the very begetting of a child would be murder, since the child will surely die; and you cannot build roads or have ships at sea without deaths being predictable.6
So the absolutism is not the crude thesis that any causal connection to a death makes an agent a murderer. The distinction between what is intended — as end or as means — and what is merely foreseen as a side-effect is morally load-bearing, and the absolute prohibition attaches to the former. What makes the position absolutist rather than merely presumptive is precisely that the prohibition on intentional killing of the innocent admits no exceptions negotiated case by case.
The good end sanctifies only such means as are either good in themselves or fall under a neutral action-description; it does not sanctify means that are intrinsically evil.7 Anyone who thinks, in advance of any particular case, that it is open to question whether procuring the judicial execution of the innocent should be excluded from consideration shows a corrupt mind.
I do not say this as abuse; I say it as a diagnosis of what the willingness to negotiate the prohibition actually reveals about the structure of the agent's moral thought.
advantage to be got by deliberately killing someone is not counted as exonerating. If someone maintains that it can justify, then what is thereby justified will be murder itself.Human Life, Action and Ethics, pp. 248–249
Unsurprisingly, then, we cannot offer a sharp and simple definition of murder. But there is a central part of its extension which can be reasonably well-defined, namely the intentional killing of the innocent.Human Life, Action and Ethics, pp. 248–249
Intentional killing in warfare, or by police in fighting violent criminals, or by execution of a death sentence — all these can be murderous, but they are not necessarily so.Human Life, Action and Ethics, pp. 204–205
a particular human action of killing someone is not established with a definite character of moral evil once it is clear that it was intentional and also was private — i.e. was not an action belonging to the exercise of civil authority.Human Life, Action and Ethics, pp. 204–205
The arsonist who burns down a house, not caring that there are people there, is as much a murderer if they are burned to death by his action, as if he had aimed to kill them. This action falls squarely within a penumbra surrounding the hard-core part of the concept of murder.Human Life, Action and Ethics, pp. 207–208
you can't build roads and fast vehicles, you can't have various sports and races, you can't have ships voyaging over the seas, without its being predictable that there will be deaths resulting.Human Life, Action and Ethics, pp. 208–209
The good end only sanctifies such means as either are good considered in themselves, or would naturally fall merely under a neutral action-description.Human Life, Action and Ethics, pp. 207–208