A conditioned reflex is a temporary connection between any agent of the external world and a definite activity of the organism.

Gradualness and discipline. This is the most important thing. From the very beginning of your work, train yourself to the strictest gradualness in accumulating knowledge.

Never think that you already know all. However highly you are appraised, always have the courage to say of yourself: I am ignorant.

I will not sacrifice even the hind leg of a frog to the kind of social experiment that the Communist government is conducting in Russia.

As in all things, we suffer from excess in reading too. Many books are a burden, not an ornament.

-- Seneca

I fear the man of a single book.

-- Thomas Aquinas

Intelligence is not what you know but what you do when you don't know.

-- Jean Piaget

My predecessors ruled but I know nothing about them, and so I do what I do that people may remember me.

-- Mansa Musa

A nation's hundred-year plan rests on education.

-- Itō Hirobumi

Gentlemen, life is short. Never waste your mind on trivial matters. Study much, work much, think much, laugh much.

-- Ōkuma Shigenobu