the ability to separate the domain of causal explanations from the domain of human action justifies car manufacturers conduct collision experiments.  researching why drivers get into collisions is a totally different kind of research (one that is closer to the interests of designers).   

Separating the domain of physics from the domains of human action does not justify (or validate) anything. It may explain the physics of the accident but not its human cause (or even its predictability).

Jonas’s interpretation of Popper seems more useful to me: “Karl Popper clarified matters with his law of falsification, which is more in line with Hume's teachings that any new experience could disprove a law that had been previously thought to be certain.”

Re Kari-Hans and Jonas: I take the view that all conscious thought is intentional and has causes.

Chuck