Never waste jealousy on a real man: it is the imaginary man that supplants us all in the long run.

You may well ask me why...I took the time to write [books]. I can only reply that I do not know. There was no why about it. I had to: that was all.

The moment we want to believe something, we suddenly see all the arguments for it, and become blind to the arguments against it.

As long as I have a want, I have a reason for living. Satisfaction is death.

[...] any fool can make a discovery. Every baby has to discover more in the first years of its life than Roger Bacon ever discovered in his laboratory.

Never repeat old grievances.

Money enables us to get what we want instead of what other people think we want.