There are several kinds of truths, and it is customary to place in the first order mathematical truths, which are, however, only truths of definition. These definitions rest upon simple, but abstract, suppositions, and all truths in this category are only constructed, but abstract, consequences of these definitions ... Physical truths, to the contrary, are in no way arbitrary, and do not depend on us.

It appears that all that can be, is. The Creator's hand does not appear to have been opened in order to give existence to a certain determinate number of species, but it seems that it has thrown out all at once a world of relative and non-relative creatures, an infinity of harmonic and contrary combinations and a perpetuity of destructions and replacements. What idea of power is not given us by this spectacle! What feeling of respect for its Author is not inspired in us by this view of the universe!

Genius is only a greater aptitude for patience.

All the work of the crystallographers serves only to demonstrate that there is only variety everywhere where they suppose uniformity ... that in nature there is nothing absolute, nothing perfectly regular.

For the little that one has reflected on the origin of our knowledge, it is easy to perceive that we can acquire it only by means of comparison. That which is absolutely incomparable is wholly incomprehensible. God is the only example that we could give here. He cannot be comprehended, because he cannot be compared. But all which is susceptible of comparison, everything that we can perceive by different aspects, all that we can consider relatively, can always be judged according to our knowledge.

There are several kinds of truths, and it is customary to place in the first order mathematical truths, which are, however, only truths of definition. These definitions rest upon simple, but abstract, suppositions, and all truths in this category are only constructed, but abstract, consequences of these definitions ... Physical truths, to the contrary, are in no way arbitrary, and do not depend on us.

The style is the man himself.