5. A man is killed _indirectly_, or _incidentally_, when he perishes in consequence of certain means employed towards a certain end, without his death being willed by the employer of those means, or in any way serving that agent to the furtherance of the end that he has in view. If a visitor to a quarry were standing on a piece of rock, which a quarryman had occasion to blast, and the man fired the train regardless of the visitor, the latter would be _incidentally_ killed. Now incidental killing, even of the innocent, is not under all circumstances unlawful. Where the end in view is in the highest degree important, the means may be taken thereto, provided always that such an issue as the shedding of innocent blood be not itself the means discerned and elected as furthering the end: for no end however urgent can justify the employment of any evil means. (_Ethics_, c. iii., s. ii., nn. 3, 13, pp. 32, 36.) Suppose in the instance just given the quarryman saw that, unless that piece of rock where the visitor stood were blown up instantly, a catastrophe would happen elsewhere, which would be the death of many men, and there were no time to warn the visitor to clear off, who could blame him if he applied the explosive? The means of averting the catastrophe would be, not that visitor's death, but the blowing up of the rock. The presence or absence of the visitor, his death or escape, is all one to the end intended: it has no bearing thereon at all. 6. We must then distinguish between _means_ and _circumstances_. The means help to the end, the circumstances of the means do not. When the end is of extreme urgency, circumstances may be disregarded: the means become morally divested of them. So I have seen an island in a river, a nucleus of rock with an environment of alluvial soil. While the stream was flowing placidly in its usual course, the island remained intact, both rock and earth. But when the water came rushing in a flood, which was as though the island itself had gone speeding up the river, the loose matter at its sides was carried away, and only the central rock remained. The ordinary flow of the river past the island, or the gentle motion of the island up-stream, keeping all its bulk, represents a man acting for an end to which reason attaches no great importance. He must then take a diligent review of all the circumstances that have any close connection with his action, to see if there is any that it would be wrong for him to will directly. And if there is, he must abstain from willing it even indirectly: that is, he must abstain from doing the action, which cannot be done without that objectionable circumstance attending it. On the other hand, the floating island being towed rapidly up-stream, with its loose sides falling away, portrays the condition of one acting for a purpose of imperative urgency: he considers the means to that end, and if they are good, he concentrates his will upon them and uses them,