Man is neither angel nor beast.

By a peculiar prerogative, not only each individual is making daily advances in the sciences, and may make advances in morality (which is the science, by way of eminence, of living well and being happy), but all mankind together is making a continual progress in proportion as the universe grows older. So that the whole human race, during the course of so many ages, may be considered as one man who never ceases to live and learn.

Reverend Fathers, my letters did not usually follow each other at such close intervals, nor were they so long.... This one would not be so long had I but the leisure to make it shorter.

We are never in search of things, but always in search of the search.

The present is never the mark of our designs. We use both past and present as our means and instruments, but the future only as our object and aim.

Curiosity is nothing more than vanity. More often than not we only seek knowledge to show it off.

If it is an extraordinary blindness to live without investigating what we are, it is a terrible one to live an evil life, while believing in God