> As I said elsewhere, your thought process is all over the place.
No, my thought process has been in exactly the same place the entire time.
> If you meant that firstborn children don't have _older_ siblings then you chose a poor way of communicating that.
My HN comments are not perfect prose, nor are they intended to be. Nonetheless, you can and in fact should assume that I'm not insane. What I meant was that firstborn have no siblings when they're born, and older siblings are the only relevant siblings as far as "watching over" is concerned.
> But to rebut your statement, as someone else pointed out, firstborn children would often have cousins and neighborhood kids watch them.
I've already addressed this in another comment: https://news.ycombinator.com/item?id=39553084
To me it gives the impression of a semi-mythical tale. Other than for occasional, specific babysitting gigs (usually paid), I've personally never "watched over" other children, whether a younger sibling, a neighborhood kid, or a cousin (all of whom lived at least hundreds of miles away). It's not something that happened in general. Kids are generally busy being kids themselves, doing their own things, and playing with their own friends. Perhaps in the distant past there was little in life except one's own extended family, but that past is long gone.