I know there are lots of everyday moments of humans being kind to each other, but do you have any good examples on a wider scale to counter that capitalist realist idea?
I usually try and invoke the fact that humanity for hundreds of thousands of years lived in tribes where they had to co-operate or they would die and that "human nature" is just the product of the system under which you live, but are there any better examples you've found to convince your lib acquaintances?
I feel like one of the major hurdles towards getting somebody to become a leftist is the idea that humanity can, if organized democratically and if properly educated and with the right ideas of solidatory instilled, create a better system than the capitalists or technocrats have created. It's easy to look around and superficially see everybody as bumbling idiots or greedy assholes, particularly if you're socially atomized and apathetic, and so conclude that the working class, if left to it's own devices, would infight and crumble.
Or is this just one of those axiomatic things where if somebody you know believes it, it's very difficult to make them not believe it through historical examples unless they do major soul searching after a personal crisis?
I think, in a sense, Darwinism can be applied to social relations, and what we see is that evolutionary pressure has selected for humans to be social and cooperative by nature (it is to the benefit of the proliferation of humanity to be cooperative). The sort of feudal idea of "I could kill my neighbor and take his stuff and be richer" is correct, but there is some force in human society which prevents us from living like this. One could argue it is the state, but the state has not always existed and certainly so in its current form. The state is also a manifestation of social relations (if for instance, humans all decided to kill our neighbor and take his stuff, the state would not exist), so even in this Hobbesian line of thought, there is a tendency towards submission to the greater good.
Of course I am not a Hobbesian and I think what we see is that the division of labor allows for a greater production, therefore a greater surplus, and therefore a greater proliferation of humanity. A division of labor necessitates a degree of social trust though and since the division of labor predates the state apparatus, that trust must be somewhat innate to our genetics. Indeed we see things like the ability to remember human faces or our wide vocal range which must have evolved for a socially cohesive unit. We see these traits in many other creatures with social systems.
All of this is to say, that we did in fact evolve as social creatures and whether that social fabric is maintained through collective violence against those who violate it or that we recognize our common material interest in social cohesion, we are by nature collaborative and respectful of one another rather than constantly seeking to exploit, It is the selective factors of the bourgeois market, a system thrust upon us by the bourgeois class, which promotes greed. There might be an argument that the market is a natural outgrowth of accumulation (a very deterministic approach though not entirely out of line in Marxism), but this has as much merit as the counterargument that the market will be overthrown for planned production based upon cooperative human nature.