Also, although it doesn't show up too much in the predictions you chose, people in 1901 had much lower levels of rationality than people from the 20th century. For instance, I'd expect someone from 1901 to think gay marriage is absurd, because beliefs about that have a heavy religious component and religion ruled people's lives in 1901 in a way that it does not now.
First even 1901 atheists would consider gay marriage absurd. Also, in order to establish that this constitutes a lower level of rationality, you need to do more then show that their beliefs differ from ours, after all they looking at us would conclude that we are being irrational for not considering it absurd. What argument would you present to them for why they are wrong?
First even 1901 atheists would consider gay marriage absurd.
Do you have any evidence for this?
Suppose I told you that I knew for a fact that the following statements were true:
You’d think I was crazy, right?
Now suppose it were the year 1901, and you had to choose between believing those statements I have just offered, and believing statements like the following:
Based on a comment of Robin Hanson’s: “I wonder if one could describe in enough detail a fictional story of an alternative reality, a reality that our ancestors could not distinguish from the truth, in order to make it very clear how surprising the truth turned out to be.”1
1Source: http://lesswrong.com/lw/j0/making_history_available/ewg.