As every divided kingdom falls, so every mind divided between many studies confounds and saps itself.

Just as eating contrary to the inclination is injurious to the health, so study without desire sports the memory, and it retains nothing that it takes in.

Learning never exhausts the mind

A good painter is to paint two main things, men and the working of man's mind.

Learning never exhausts the mind.

Just as iron rusts from disuse, even so does inaction spoil the intellect.