Coming up tails
Heads on a science apart
have always puzzled me. I think now I have found an interpretation that makes sense:
Heads/tails (as in "coin toss") connects two metaphors.
1. "Coming up tails" means "the coin toss always has the same result" which in turn means "fate leaves us no choice" or "we can't escape destiny".
2. "Head/Heads on a science apart" means "this leads towards a science that stands out on its own" or, more figuratively, "this is pretty much an impossibility" (I haven't heard "a science apart" used in that sense in English yet, but its German translation "eine Wissenschaft für sich" is an idiom meaning "a very complicated matter").
Combined, it means "trying to change fate / escape destiny is next to impossible".