What is Longtermism and why does it matter?

There's a counter-argument to be heard that grand "Longtermism" is actually part of the problem.

Maybe modern society does understand all too well that decisions affect the entire future of humanity, and is both completely happy about our course, and completely wrong about it.

The concept of "the future" brings it's own problems. More of what is needed is "presence", the ability to act well and make moral decisions right here, right now, in this moment. Because almost every future we can imagine is not the one that's going to happen. This leads to a kind parochialism and omnipotent thinking.

Often the "right thing", in a Kantian sense, is immediate and instinctive, but then comes the rationalisation, backtracking, bargaining, procrastination and exceptionalism that is supported by an over-complex ideology about "the future".