by Jeroen Bouterse
I’m not sold on longtermism myself, but its proponents sure have my sympathy for the eagerness with which its opponents mine their arguments for repugnant conclusions. The basic idea, that we ought to do more for the benefit of future lives than we are doing now, is often seen as either ridiculous or dangerous.
Usually, this takes the form of thought-experiments in which longtermists are supposed to accept major harm to humanity now in the hope of some huge potential benefit later. Physicist and YouTuber Sabine Hossenfelder, after boasting that she couldn’t be bothered to read William MacAskill’s book What We Owe the Future (“because if the future thinks I owe it, I’ll wait until it sends an invoice”), goes on to interpret a paper by MacAskill and his colleague Hilary Greaves in this way: “a few million deaths are acceptable, so long as we don’t go extinct.”[1] Phil Torres takes aim at an updated version of the same paper, in which Greaves and MacAskill argue that possible futures with huge numbers of people, even if they are unlikely, represent an expected value that outweighs that of the near future. He reads it as implying that MacAskill and Greaves might well press a button that lets 1 million people die now, to increase the chance that 100 trillion people will be born later.
That does sound inhumane, though luckily it seems unlikely that these two Oxford professors would get their hands on such a button, and that they would have a sufficiently strong credence in its reliability. Even aside from that, however, I have learned to stop worrying about what longtermists would do when presented with mega-trolley problems: every time some hostile rendition of a longtermist argument has shocked me into checking out the source, the original text turned out to be orders of magnitude less scary than I was led to believe. If you want to make the case that MacAskill and Greaves would support mass slaughter now for a tiny chance to benefit the future, you have to be willing to stretch specific parts of their argument and ignore the part where they, for instance, explicitly factor in a no-harm criterion (p. 5; p. 30). The idea that longtermist thinkers are making the world safe for cold-hearted utilitarianism, in which faraway ends justify any means, only gets off the ground if you are willing to believe that they are dishonest about where their arguments are taking them. Read more »