For instance: age of sexual consent, age for legally drinking alcohol, age for driving, age for voting, age for participating in pornography
Depending on the place, each of those requires a different minimum age. Why is that? Are some activities “more adult” than others? Using USA as an example: legal drinking age is 21, legal driving age is 16, age of consent varies between 16-18.
Not asking about different countries/states having different ages, but any single place having different ages for different adult activities
The idea that virtually nothing in life is actually derived from first principles, and is instead derived from sometimes very random history, would probably deserve to go near the top of any FAQ for life. Might be one of the most common misconceptions in the entire world, the idea that somehow, some way, someone had to have created things the way they are intentionally, for specific reasons.
Instead of things just working out this way because of a handful of barely-related decisions made by basically random people here and there through history, and everyone else just going along with it because they mainly just care about their own lives, who they’re dating/marrying, what job they have and what’s for dinner tonight, far more than they care about the voting age.
Our world is far more haphazard than planned, overall.
Yep. But also, fake first-principles explanations are commonly offered when people ask “Why is the rule thus-and-so?”
“Why can’t I vote yet? (or: marry, buy a gun, etc.)?”
“You’re not old enough.”
“Why not?”
“Because 18-year-olds are just more mature than 15-year-olds.”
“Why? Who says?”
“Um. The Constitution!”
“But it used to say something different.”
“Yep. We know better now.”
“Says who?”
“Democracy!”
The 15-year-old correctly assesses that these are not real explanations, but rather rationalizations of a rule that was decided not from first principles, but rather through people in history arguing over it, sometimes protesting or even fighting, and changing the rules.