what makes us stronger

Canto: So I hear you've been waxing philosophical, Jacinta.
Jacinta: Insofar as I'm able, mate. I've been thinking about the course of history, and how it relates to immune systems and recovery from disease and so forth.
Canto: Sounds like a bit of a vague connection. Fill me in.
Jacinta: Well this morning, while reading the intro to a book on the 'underground railroad' in the slave days before the US civil war, I came upon this sentence:

Instances of interracial cooperation and collaboration represented a countervailing force to the institution of slavery and eventually helped bring about the destruction of the peculiar institution.

Now the odd term 'peculiar institution' made me think of a foreign body, in immunological terms, which causes a lot of activity within a cell or tissue, a marshalling of forces to fight the invader, or the 'peculiarity', in order to re-establish that optimal equilibrium state we describe as 'health'.
Canto: 'Our peculiar institution' was how the south euphemised slavery in the early days - that's to say, something specific to, or peculiar to, us. Using the 's' word was deemed improper, of course.
Jacinta: I was thinking that health is historically what we've been out to achieve, and that, ultimately, those movements, forces, institutions that are not conducive to health are always vanquished, ultimately, though the struggle is hard, and virtually ongoing. Our immune system is never perfect, and there are always dormant forces that could trigger new, threatening outbreaks. They say that history is generally written by the victors, and while that's obviously true, it suggests distortions about our view of the past that I'm not so sure exist, or are much exaggerated. I mean some victories were necessary, and maybe inevitable, though that seems to diminish the sacrifices and the efforts of those who fought for that victory. Nazism could never have won, ultimately, it was too destructive of the body politic, and the same might be said for the peculiar institution - it could never have been allowed to continue, indefinitely. The disappearances of the so-called dirty war in Agrentina had to be addressed for the sake of health. South African apartheid could never ultimately survive, and it had to be redressed. Do you see what I'm getting at?
Canto: Yes I do, and I think you're gesturing towards something in evolution - the organism seeks to reproduce itself, to continue its line, and it has to shake off invaders, foreign bodies, peculiarities [all of which are intent on their own survival], thereby becoming stronger, more 'sophisticated', more complex - the more invaders it has to fight off, the more complex and sophisticated it necessarily becomes.
Jacinta: And recognizing the importance of history, of memory - though that can be distorting, designed as it is partly to comfort, history's the thing - is a vital component of that armory which helps us to survive, and to meet new challenges. It teaches us not only a heap of life lessons for negotiating the future, but also what to value, the resources and characteristics that have made it though the fire.