Mathematics is the poetry of logic and the music of reason.
Is human reason, then, without experience, merely by taking thought, able to fathom the properties of real things? In my opinion the answer to this question is, briefly, this: — As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.
First, I must distinguish between that which always is and never becomes and which is apprehended by reason and reflection, and that which always becomes and never is and is conceived by opinion with the help of sense.
Let him alone, he has a way of stopping anywhere and losing himself without any reason. I believe that he will soon appear; do not therefore disturb him.
There are, then, these three means of effecting persuasion. The man who is to be in command of them must, it is clear, be able (1) to reason logically, (2) to understand human character and goodness in their various forms, and (3) to understand the emotions-that is, to name them and describe them, to know their causes and the way in which they are excited.
Reason is a light that God has kindled in the soul.
Lastly, in each of his infinite bodies there would be already present infinite flesh and blood and brain — having a distinct existence, however, from one another, and no less real than the infinite bodies, and each infinite: which is contrary to reason.
A vulgar mechanick can practice what he has been taught or seen done, but if he is in an error he knows not how to find it out and correct it, and if you put him out of his road he is at a stand. Whereas he that is able to reason nimbly and judiciously about figure, force, and motion, is never at rest till he gets over every rub (from a letter dated 25 May, 1694).
The man who looks only outside and quails before the big battalions has no resource with which to combat the evidence of his senses and his reason.
The more critical reason dominates, the more impoverished life becomes. When reason is overvalued, the individual suffers a loss. Relying more on facts and rationality than on imagination and theory detracts from the quality of a person’s intellectual life.