These illustrations suggest four general maxims[...]. The first is: remember that your motives are not always as altruistic as they seem to yourself. The second is: don't over-estimate your own merits. The third is: don't expect others to take as much interest in you as you do yourself. And the fourth is: don't imagine that most people give enough thought to you to have any special desire to persecute you.
Bertrand RussellSome care is needed in using Descartes' argument. "I think, therefore I am" says rather more than is strictly certain. It might seem as though we are quite sure of being the same person to-day as we were yesterday, and this is no doubt true in some sense. But the real Self is as hard to arrive at as the real table, and does not seem to have that absolute, convincing certainty that belongs to particular experiences.
Bertrand Russell