At the end of the last volume of his three-volume On What Matters, Derek Parfit says that he had written so little about what matters. It is not true. Maybe the trilogy says hardly what matters but it says a lot about what matters. Parfit added that he hoped to say more about what matters in a fourth volume (p. 436), but, alas, it will not happen, for he died yet before the third volume had been published.
An author has often another view on his work than his readers and I think that this is here also the case. In order to show that the trilogy discusses really what matters – and not only about what matters –, I cannot give an extensive analysis, but here are some examples (I quote from Volume Three):
“When we ask”, so Parfit, “whether some act’s effect would make [an] act right or wrong, many of us [believe] that we can ignore very small benefits or harms.” For instance: “[W]e ought to save one person from a year of pain rather than saving each of many people from only one minute of similar pain”, so many believe. Parfit doesn’t agree: “Suppose that another million people would, without our help, have two years of pain. When applied to this case, [the thesis] is clearly false. If we million people saved each of these other people from one minute of pain, we together would save these people from two years of pain” (p. 422)
Although it is true, nevertheless we could prefer to spread the pain among one million people, since we find one year of pain for one person terrible, and one minute of pain for each of one million people tolerable. Parfit admits that this case is quite unlikely to occur, but that as such the argumentation is not unreal:
“We can often act in ways that would be better for us, or for a few other people, but would also be worse for many other people. The bad effects on each of these other people may be slight, so that we assume that they don’t matter, but when very many of us do what has such slight effects on very many people, the harm we do may be much greater than the benefit we give ourselves. For a clear though trivial example, if we drive ourselves to work rather than taking a bus, we may shorten our time spent traveling by thirty minutes, but by increasing congestion we may lengthen a thousand other people’s journeys by one minute, so that these people together lose a thousand minutes a day. Similar claims apply when there is overfishing or overgrazing. If many fishermen use larger nets, each may cause himself to catch a few more fish, but each may also cause others to catch many fewer fish.” (p. 423). So individually few win much but altogether many lose through this selfish behaviour. In other words, also an action with individually unnoticeable effects for others may be wrong, despite what many people think. “[Such an] act is wrong ... because this act imposes on others a significant amount of pain, even though the amount imposed on each of these other people would be very small.” (pp.431-2)
Indeed, each of us enjoys the gadgets and conveniences of modern life and if I buy a barbecue or drive to the supermarket, because I am too lazy to take my bike, the contribution of this single purchase or this idle act to the air pollution is imperceptible. But I am not alone on this world. “When each of us contributes to global warming, none of our acts will be significantly worse for anyone, but we together make things go much worse for many people. ... [I]t would be clearly better if many fewer people acted in these ways. Many fewer people would then be killed or harmed” (p. 432)
Who says that On What Matters does not says what matters?
ReferenceParfit, Derek, On What Matters. Volume Three. Oxford, etc.: Oxford University Press, 2017.