Everything is self-evident.

And thereby make ourselves, as it were, the lords and masters of nature.

Human wisdom remains always one and the same although applied to the most diverse objects and it is no more changed by their diversity than the sunshine is changed by the variety of objects which it illuminates.

If we possessed a thorough knowledge of all the parts of the seed of any animal (e.g. man), we could from that alone, be reasons entirely mathematical and certain, deduce the whole conformation and figure of each of its members, and, conversely if we knew several peculiarities of this conformation, we would from those deduce the nature of its seed.

Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.

Conquer yourself rather than the world.

We do not describe the world we see, we see the world we can describe.