Under your test, no one could ever be PROVEN of doing anything knowingly without having some sort of device that looked into their mind. And even then I think you would have reservations about its accuracy AT THE TIME of the act. You have to infer intent from surrounding actions that the person takes. From those actions it is pretty clear that Palmeiro knowingly took steroids. Just because a liar says he didn't do something doesn't mean you have to ignore everything else and say that raises doubt. It only raises UNreasonable doubt. BTW, he likely will not be convicted of perjury because they have no evidence that he was doing it BEFORE he testified(he tested positive afterwards), NOT because they have no evidence of intent. Prosecutors across this country get juries to infer intent from far more tenious cases than this. Maybe there's something wrong with your country then. Or your lawyers. Or your juries. Or all three. That wouldn't surprise me. What evidence of intent do they have? From what surrounding actions are you infering intent? And on what evidence are you calling Palmeiro a liar? Or is this more guilty until proven innocent suppositioning? Testing positive for drugs doesn't prove that you knowningly took them, and took them to gain an unfair advantage. The accepted legal standard of proof is REASONABLE doubt, not a "you can't prove Martians didn't build the Pyramids" level of doubt.