And believe me, if I were again beginning my studies, I should follow the advice of Plato and start with the mathematical sciences, which proceed very cautiously and admit nothing as established until it has been rigorously demonstrated.

Their vain presumption of knowing all can take beginning solely from their never having known anything; for if one has but once experienced the perfect knowledge of one thing, and truly tasted what it is to know, he shall perceive that of infinite other conclusions he understands not so much as one.

Spots are on the surface of the solar body where they are produced and also dissolved, some in shorter and others in longer periods. They are carried around the Sun; an important occurrence in itself.

It has always seemed to me extreme presumptuousness on the part of those who want to make human ability the measure of what nature can and knows how to do, since, when one comes down to it, there is not one effect in nature, no matter how small, that even the most speculative minds can fully understand.

Philosophy itself cannot but benefit from our disputes, for if our conceptions prove true, new achievements will be made; if false, their refutation will further confirm the original doctrines.

I do not know what to say in a case so surprising, so unlooked for and so novel.

It is surely harmful to souls to make it a heresy to believe what is proved.