It should be abundantly clear that I am willing that evil should be done in order that a greater good may result: viz. my support for the war in Iraq, my suggestion that the Pope encourage believers to shoot abortionists, and my concession that if the eternal damnation of non-Muslims (for instance) was positively proved, a reasonable moral response would be to destroy our species. If these instances of Menachem Begin’s dictum ‘some ends justify some means’ fall short of the hypothetical you are envisaging, I am a little nervous to think of what you might be contemplating...
In a technical sense, it is true that I would reject ‘the end justifies the means’, if ‘justify’ is meant in the ‘justified by faith’ sense of ‘made perfectly okay’. I think participation in a just war is not without sin. I think it is intrinsically bad to shoot abortionists rather than appeal to their reason. I think wiping out our species would be bad. We can quite easily find ourselves in options where all the options available to us are quite, quite, evil, and picking the best of a bad lot does not make us ‘good’.
I am curious about your belief that there is a relative morality ‘for humanity.’ This would seem to fall short of the strong relativist thesis that good and evil are social constructs. If you reject a morality that is intrinsically ‘true’, like mathematics, are you making the assertion that morality is a biological rather than social construct? That we have, as a species, evolved to consider some things good and some things evil, regardless of our cultural background? This is not implausible. However, I regret that if I believed morality was biologically constructed- and this is only me- I would also believe it was absolutely non-binding and irrelevant to me personally. If we had evolved to consider some things good and some things evil- and this consideration does not correspond to any objective reality- I would consider morality just another irritating fact of human biology to be overcome, like our human addiction to sugar, dependence on eating dead animals, or urge to have sex with lots of people.
But, Allahu akbar, I do not believe any such thing! I will close with the words of Chesterton’s Father Brown:
‘Reason and justice grip the remotest and loneliest star. Look at those stars. Don’t they look as if they were single diamonds and sapphires? Well, you can imagine any mad botany or geology you please. Think of forests of adamant with leaves of brilliants. Think the moon is a blue moon, a single elephantine sapphire. But don’t fancy that all that frantic astronomy would make the smallest difference to the reason and justice of conduct. On plains of opal, under cliffs cut of pearl, you would still find a notice-board, “Thou shalt not steal.”’