people were advocating meat eating because it contributed to the development of the brain, and i argued that a similar argument could be used to advocate war, to show how meaningless the first argument was.
I think you're on to something, though in the exact opposite way that you're intending.
Conflict, of which war is one form, has been a major cultural selector for innovation. Conflict is, itself, a sub-category of hardship, which all manners of things operating on evolutionary algorithms benefit from, as being forced into solving problems leads to overall improvement. Therefore, it can be said that conflict and hardship should be encouraged until such a time as it becomes superfluous, for there is no greater motivator than difficult times, at least for those capable of great works.
Of course, not all the cultural developments fostered by hardship are beneficial; as the driving motivator is simply to end or otherwise answer whatever unpleasant circumstance one is faced with, we end up with weak, side-stepping developments meant to address the problems in a way that would remove them, but wouldn't drive us to further, greater heights, and in fact actively discourage such by removing the impetus to progress. These are, obviously, not technological, but social developments, that for instance suggest to solve the unpleasantness of war with "everyone should like, be nice to everyone and shit, maaaan," instead of with "build a better weapon to slaughter your enemies, or otherwise progress to out-compete them."
Some of it could be said to be treating causes, rather than symptoms, but when treating symptoms, there's always room for improvement; you never
truly answer the problem, you just become progressively better at doing various things tangentially related to it. If the goal is to become better, the absolute worst thing to do is address the cause, as it removes the reason to become better in the first place. Therefore, decisive social solutions to hardships and conflicts are harmful to society, as progress thrives best when there is a visible problem to attack. They also tend to spawn annoying things like "but, like, if
people shouldn't suffer, than like,
cows shouldn't either, cause like, suffering is bad or something, and they're like, things and shit, maaaaaaaaaaan."
There: a rational argument on conflict, hardship, and suffering, and the social benefits thereof. Naturally, eating meat doesn't
still provide the same benefits (selectors for increased intelligence) it did, and you're misinterpreting why that was brought up in the first place, but
conflict still does, though it's hopefully nearing the end of its usefulness (though perhaps the idea of a state where technological progress is given proper support just because it's fucking awesome is just a pipe dream, considering how quick the masses are to forget about anything that's not shiny and answering a pressing need (or compellingly fabricates a pressing need, a la the iPad, also known as the most pointless fucking thing ever marketed to unprecedented success; even snake oil was booze laced with opium...
)). I'll leave it to the reader to decide how much of this is facetious.