The impact is hundreds of trillions of lives

The spatiotemporal details of any extinction process would be of great ethical significance. The tens of millions of deaths in the Second World War and how they were distributed among the warring parties would be far less significant, I'd say, than whether half a billion humans managed to live onwards for a century when an unstoppable slide towards extinction had begun, and whether the process started with the swift extinction of those nations which had done least to cause the fatal nuclear exchange, greenhouse calamity or whatever. All the same, I suggest the following. Whether the extinction process took only a fraction of a second, spreading outward at almost the speed of light from a single centre (once again read onwards), or was instead a matter of many decades and much geographical complexity, would be far less important than the fact that humans would be dying out before beginning serious efforts to spread across their galaxy.

This is because such efforts would probably succeed; because the number of human lives which would then be lived would probably be in the hundreds of trillions, assuming that our much modified descendants could be counted as 'humans'; and because most of the lives would probably be more worth living than ones in our technologically primitive era. The weightiest of all ethical imperatives could be Spread Through The Galaxy! The extinction of the human race before galactic colonization could begin would be immensely tragic because of the vastly many worthwhile lives that would then have no possibility of being lived.

Many a professional philosopher has suggested, in contrast, that the loss of a future containing countless richly satisfactory human lives would be hardly any loss at all. Its drawback would be simply that folk would have hoped in vain that the future would contain such lives. Its ugliness, that's to say, would lie in its non-fulfilment of things wished by the dead, as when computer error sends Aunt Jane's fortune to the orphanage, not the Home for Abandoned Cats she recommended to her executors. Just what, the philosophers inquire, could anyone have lost through not being born, for just who wouldn't have been born? People possess identities only after coming into the world, they protest, and only people with identities can lose anything.

Note, though, that the very same philosophers declare (a) that it would be wicked for people to give birth if they could be confident that those born (whoever they were, so let's here forget the little matter of their identities!) would have lives that were very miserable, and (b) that generating such lives would be more evil, the greater the number of those lives. But, I ask, isn't there too weird an asymmetry here? Little or no duty, say our philosophers, to generate humans likely to have lives richly worth living even if you could generate trillions of them by snapping your fingers, because they wouldn't have identities until generated, and yet there's a firm obligation not to generate humans likely to be miserable, and above all not to generate many of them. Well, to accept that sort of thing you must perhaps be a professional philosopher.

It seems to me, anyhow, that the duty to attempt galactic colonization is immensely strong-assuming, that's to say, that there'd not be trillions of extraterrestrials in danger of extermination or enslavement. Might humankind plausibly become extinct before the process could get started? Galactic colonization will probably begin within a couple of centuries if we don't annihilate ourselves during that period. What chance, then, does the human race stand of surviving for another two hundred years?