Try to ever correct a professor at a university. They will hate you forever. Who the fuck you think you are, being smarter than them... I guess this means most professors are idiots.
It means that you are very unlikely to be correct and, in the unlikely event that you are correct, you most certainly aren't educated enough on the topic to list why you are correct while he is not. Rather than speaking out in class, if this is the case, then send an email with a well spoken request for a further explanation of that topic with the science papers that you believe contradict him.
In the vast majority of cases, you are most likely the incorrect one while the professor is correct. Professors can be incorrect, but this situation is the outlier to the norm. But I do agree that some professors will resent you for questioning them, however, there is no reason to make that resentment more likely and/or stronger by interupting them in the middle of class.
In the vast majority of cases, you are most likely the incorrect one while the professor is correct. Professors can be incorrect, but this situation is the outlier to the norm. But I do agree that some professors will resent you for questioning them, however, there is no reason to make that resentment more likely and/or stronger by interupting them in the middle of class.