If the course of human history is governed by emergent macroforces far beyond any individual then what does it matter what we do when it comes to politics? If the end of feudalism was determined by productive technologies being no longer dependent on land; if world war was inevitable because of the logic of states and not the personalities of various state leaders; if the emancipation of women and the sexual revolution were caused by the changing nature of work and the contraceptive pill; and so on.
But if human societies are complex enough that they exhibit chaotic behaviour – where one person can be the threshold between two vastly divergent courses – this does not solve the problem. The actions of a single person may affect history but in ways unpredictable by the person performing the intervention. Perhaps a charismatic individual rises to lead a movement but produces a counterreaction that actually sets the movement back.
It’s entirely possible of course, that individuals acting in good faith reliably produce better macro-outcomes than individuals choosing not to act or acting selfishly, but we must be aware that we are biased in assessing this since we want it to be this way. Or at least I want it to be this way. Perhaps for others it is a comfort to think we cannot affect history since then we can be politically inactive whilst sparing our consciences.
Real changes occur though through the combined actions of individuals; individuals who are perhaps not as self-conscious as me, who act from feeling without reflecting too much on whether their actions will ultimately prove decisive. Perhaps, because I need proof before I act that I will be important, I am the truly selfish one.