People often argue that X is hugely important because it affects everything else. Sleep is so important because it affects your whole day. You should value your health more than anything because you need it for everything else. And your freedom too. And friends, and food. AI is the most important thing to work on because you could use it to get anything else. Same with anything that makes money, or gains power. Also sociology, because it’s about understanding people, and everything else we care about depends on people’s behaviour. And maths, science, and engineering are more important than anything because they illuminate the rest of the world, which is the most important thing too. Politics is most important because it determines the policies our country runs under, which affect everything. Law is similar. I assume garbage collectors know they are doing the most important thing because without garbage disposal society would collapse.
It turns out an awful lot of things affect everything, and a lot of them affect a lot of things a lot. That something has a broad influence is certainly a good starting criteria for it being important. It’s just a really low bar. It shouldn’t be the whole reason anyone does science or repairs roads, because it doesn’t distinguish those activities from a huge number of other ones. There is more than one thing that affects everything, because the set of things we might care about are not causally organized like a tree, they are organized like a very loopy web of loops.
Often this ‘affects everything’ criterion is not even used on any relevant margin. It is used in the sense that if you didn’t have sleep or any understanding of humans at all you would be in a much worse situation than if you had these things in abundance. A better question is whether sleeping another half hour or dedicating your own career to sociology is going to make a huge difference to everything. An even better question is whether it’s going to make an even bigger difference to everything than anything else you could do with that half hour or career. This is pretty well known, and applied in many circumstances, but for some reason it doesn’t stop people arguing from the interconnectedness of everything to the maximal importance of whatever they are doing.
Perhaps it is psychologically useful to have an all purpose excuse for anyone doing anything that contributes at all to our hugely interconnected society to feel like they are doing the most important thing ever. But if you really want to do something unusually useful, you’ll need a stronger criterion than ‘it affects everything’.