He was wrong because there are so many systems of thought; because he wasn't accounting for or aware of the existance of subconscious thought; because thoughts

He was wrong because there are so many systems of thought; because he wasn't accounting for or aware of the existance of subconscious thought; because thoughts are context dependant; and of course because all formal systems of this sort tend to suffer incompleteness. However, I have only the greatest respect, as asking a question that leads to so many deep and interesting answers is far more difficult and important then having a "correct hypothesis".