urgency of end in view would be requisite to justify the using of that
means: in other words, no end possible to man can ever justify an evil
means.

_Readings_.--St. Thos., 2a 2a, q.64, art. 6; Cardinal de Lugo, _De
Justitia et Jure_, disp. 10, n. 125.


SECTION II.--_Of Killing done Indirectly in Self-defence_.


1. On the question, whether it is lawful for one man to kill another
in self-defence, St. Thomas writes (2a 2a, q. 64, art. 7):

"There is nothing to hinder one act having two effects, of which one
only is within the intention [and election] of the doer, while the
other is beside his intention [and election, that is, is neither
intended as an end nor elected as a means].... From the act therefore
of one defending himself a twofold effect may follow, one the
preservation of his own life, the other the killing of the aggressor.
Now such an act, in so far as the preservation of the doer's own life
is intended, has no taint of evil about it, seeing that it is natural
to everything to preserve itself in being as much as it can.
Nevertheless, an act coming of a good intention may be rendered
unlawful, if it be not in proportion to the end in view. And
therefore, if any one uses greater violence than is necessary for the
defence of his life, it will be unlawful. But if he repels the
violence in a moderate way, it will be a lawful defence: for according
to the Civil and Canon Laws it is allowable _to repel force by force
with the moderation of a blameless defence_. Nor is it necessary to