The more necessary a thing is for living beings, the more easily it is found and the cheaper it is; the less necessary it is, the rarer and dearer it is.
Do not consider it proof just because it is written in books, for a liar who will deceive with his tongue will not hesitate to do the same with his pen.
Consequently he who wishes to attain to human perfection, must therefore first study Logic, next the various branches of Mathematics in their proper order, then Physics, and lastly Metaphysics.
There is no difference between the worry of a human mother and an animal mother for their offspring. A mother’s love does not derive from the intellect but from the emotions, in animals just as in humans.
The same is the case with those opinions of man to which he has been accustomed from his youth; he likes them, defends them, and shuns the opposite views.
