That field is also prone to change based on nothing but politics, while a soviet cardiologist, a western liberal cardiologist and a muslim cardiologist might reach the same diagnosis and prescribe you the same or similar hearth medication for your condition, that is not going to be the case with psychs
I guess some of the recent developments in the medical field where vaccines that have more net negatives than positives are recommended across the board makes me a little more skeptical as a whole.
Europeans came over with crates full of beads and could trade whatever they wanted for them. Indians allowed them more land to build ports and towns around the ports in order to trade more and before you know it, those Europeans are now Americans.
Were the early Europeans cruel for manipulating the Indians so easily?
This is a little reductive. It's not like various native americans didn't see the useful opportunities that the europeans provided to them. In central america, tribes saw a chance to overthrow the aztecs, who required a constant stream of human sacrifices from every subjugated tribe.
I remember reading early nieuw amsterdam records (which later became new york). In it they wrote about the abysmal state of the wampum that they had in the settlement. Wampum was the kind of beaded currency that local natives used. And the dutch regarded them as fungible resources, like coins. But the natives judged each piece by how nice it was, how good it looked. And before long, the dutch had only poor quality wampum and started to discover they couldn't just count the number they had.
A lot of such things go wrong between cultures. The Dutch famously bought mana hatta, "reed island" that later became manhattan, for only 60 guilders worth of goods. What the Dutch didn't realise that the local natives expected that this meant they could come over any time to visit and should expect lodging, food and gifts.
Of course then later colonials started mass producing wampum and when this caused inflation and it became untenable to trade whatever for these wampum, native americans abandoned it as a type of currency.
I think the key with something like that is that each side tries to exploit the other... because humans can be pretty devious.