OT: Superman and Stemcells

[Evil Dave]

Zen said:

Because "proof" is under the sway of "perception" and "understanding" which continually evolve. If you want to apply the "At this time, we believe:" to every fact that is presented by scientific conclusion, then it would be accurate. Science continually disproves other previsouly scientific facts, or finds and creates theories to plug the holes in otherwise grandly adopted factual systems.

It's hairier than that, but I don't wanna dig into Popper and Kuhn to remember how to argue the utter hairiness.

The short form goes kinda like this: some things which were previously the results of long chains of hypotheses are now considered facts. Mars isn't just a bright point in the sky that moves differently than the "fixed stars". We're positive it's a rocky world much more like the Earth than the Sun. Atoms are in the same Category, since you can (more or less) observe them directly with x-ray diffraction and electron microscopes. OTOH, the stuff that makes up atoms (or supposedly makes them up) isn't (yet) a real "fact".

Yeah, there's a lot of handwaving in that. Like I said, arguing it correctly is hard.