The first two are subjective decisions, and only the evidence of your own life can inform on those.
The 3rd was a political decision, one in which many people still debate on, again, either subjective or arbitrary.
The fourth, on languages, is absolutely a scientific question, indeed there's a scientific field based around it, trying to figure out how, when and what the first languages and proto-languages were.
The fifth is again, arbitrary and subjective.
Only one is open to true scientific inquiry, however, science can possibly inform you on the others, at least to a limited extent. Knowing human behavior would help you pop the question without, hopefully, facing rejection. It can help inform you of your current place in the universe, so you would know where to go from there, metaphorically. The bombing is the most difficult, understanding the human costs, and possible benefits of the decision can make it more palpable, or not, depending on your view. Math can help break down the stats on who might be the best QB, though by what standard they are judged would be arbitrary.