Are you making a claim that him changing his opinion is a negative (real question, I could not tell if you were making a value judgement from your post). I don

Are you making a claim that him changing his opinion is a negative (real question, I could not tell if you were making a value judgement from your post). I don't know enough about that specific scientist, but in general, I tend to respect scientists more when they are willing to change their opinion (assuming it's in light of new evidence and not just on a whim) and admit they were wrong previously. That isn't a bad thing, IMO, that is a valuable trait to have, which is why I tend to listen to and respect those who have that trait more than those who dogmatically stick to an opinion regardless of new information.