disregarding, or even deploring, but nowise willing or being responsible for, the evil concomitants which go with those means, but do not make for his end. Thus it is, that a circumstance which in ordinary cases goes to make the adoption of certain means reasonable or unreasonable, comes, in a case of great urgency, to weigh for nothing in the balance of reason, owing to the extreme and crying reasonableness of the end in view. Nor is this the end justifying the means, for that unhappy circumstance is never a means to the end. (_Ethics_, c. iii., s. ii., n. 8, p. 34.) 7. To illustrate by a diagram: [Illustration: C ( ) U | | A-----------------------------------E( )V ] A, the _agent_, a bead on a wire, can move only on the line AE, that alone being the line of means to the end. EV, _reasonableness of end in view_, attracting A. UC, the amount of moral evil which the _untoward circumstance_ would involve, if it were willed directly. This UC repels A, tending to jam it on the line AE, which is absolutely rigid. AE, remoteness, difficulty, and uncertainty of the end in view. AU, remoteness of untoward circumstance from means chosen, which A is just in the act of taking. Then, for lawful action, the reasonableness required in the end in view is represented by the variation-- [Illustration: UC . AE EV *varies* ------- AU ] We observe that when AU is zero, while UC . AE remains a finite quantity (representing an appreciable evil), then EV becomes infinite: that is to say, when the distance, difference, or distinction between the evil circumstance and the means comes down to nothing at all, and the evil thing actually is the very means taken, then an infinite 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 2æ, 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 2æ, q. 64, art. 7):