I guess that he was a very thorough man, through his pain and suffering and close encounter with death at a relatively early age and suffering so much physical ailments actually provided the reason for him to undergo his intense process of questioning but not only that, re-evaluating his entire life, what life really was, who (what) he - and not only he but everyone - is. He clearly saw how he was creating all the misery and even unhealthiness within in his experience of life to that point. Not to say he lived for ever or anything and the rationalwiki seems to point to the cause of his death as being proof that what he is saying is garbage more or less. But most humans do completely miss the link between their own thoughts and their resultant reality and the importance of this cannot be underestimated.