The experts of that day had naught but their religious convictions to teach them of the heavenly bodies, until Galileo came along, anyway. Nowadays, we can study such things with advanced instruments and teams of esteemed researchers. There is evidence, a substantial amount, for the proposition that certain structures of the psychopathic brain differ from the norm. I've studied it myself. Until you can construct an alternative hypothesis and provide a substantial amount of evidence for said hypothesis and formally refute the aforementioned theory or find a viable theory, devised and published by esteemed researchers, I have no reason to believe your assumptions. Bridgie, I completely agree. It's an explanation of certain characteristics of psychopathy, but not an excuse for immoral behavior, as psychopaths know what we're doing and we can control our actions. Only when the person in question does not understand the consequence of their actions and/or cannot control their actions are they truly absolved of responsibility.