We are a tad beyond handwaving, but with all the information overload it's hard to recognize scientific breakthroughs anymore.

Anyway thermodynamics did it.

https://arxiv.org/abs/1203.3271

Most people won't like this answer, because it's too impersonal. Thus the search for a more inspiring origin story continues. There is no drama in thermodynamics, no love, no revenge, although there are explosions.