My principle has ever been to attempt to overcome myself rather than fortune and to change my desires rather than the natural order. - René Descartes

On the other hand, I compared the disquisitions of the ancient moralists to very towering and magnificent palaces with no better foundation than sand and mud:

Several years have now passed since I fi rst realized how numerous were the false opinions that in my youth I had taken to be true, and thus how doubtful were all those that I had subsequently built upon them. And thus I realized that
once in my life I had to raze everything to the ground and begin again from the
original foundations, if I wanted to establish anything firm and lasting in the sciences.

I had become aware, as early as my college days, that no opinion, however absurd and incredible can be imagined, that has not been held by one of the philosophers.