History could have turned out differently, but wouldn't it require other factors to also change?
For instance, isn't European colonialism responsible for both the larger number of diseases the explorers had been carrying, but also the higher herd immunity? And that the native's relative isolation led them to be more exposed when confronted with foreign cultures?
I guess what I'm asking is, isn't this a little bit of a chicken/egg situation?
If the natives had been more aggressive in expansion, they may have had a higher exposure rate to other cultures and diseases and thereby a higher immunity to it as well as leading to more genetic diversity, and possibly having reached Europe first?
I guess the way I read your comment was implying that history could have easily been different (which you may or may not actually be stating), but the number of factors (genetic/cultural temperament, geology, etc) all have to line up over such a long period so as to basically be a fundamentally different world history than what has transpired, both before and after the actual colonisation period.
I overall agree with your point, that it was a large factor in the colonisation of the Americas, but even that aspect was far more determined or influenced by a huge range of factors that co-mingle into the history we know (and largely left to random natural processes and historical fiat).
I'm probably being overly pedantic (it is Saturday night on HN after all ;)), but I guess your statement read similarly to other "history-could-be-different" thought experiments, but seem fundamentally different (I'm contrasting that to the most common experiments, situations like the TV show High Castle and what if Germany won the war, or what if JFK hadn't been assasinated, etc).
Again, I'm not necessarily disagreeing, just following a mental thread of what would be needed in order for that change to be possible.
Having written and read all that, at the very least, I was assuming something that's probably different than what you're actually saying.
Your comment does make me wonder about some of the other accounts of European history where the Romans had a harder time invading (parts of Brittania, for example) where the cultures were written off as barbarian and completely deranged or had large myths associated with them, if disease played some part in the comparable success/failure of colonisation for those areas and the coloring of Western history in general.