Mathematics is the key and door to the sciences.
I have never met a man so ignorant that I couldn't learn something from him.
My dear Kepler, what would you say of the learned here, who, replete with the pertinacity of the asp, have steadfastly refused to cast a glance through the telescope? What shall we make of this? Shall we laugh, or shall we cry?
We must say that there are as many squares as there are numbers.
Knowing thyself, that is the greatest wisdom.
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.