All things noble are as difficult as they are rare.

Plato "Phaedrus"

The least initial deviation from the truth is multiplied later a thousand fold.

Aristotle, On the Heavens, Bk I, Chp 5

"Thus, the task is, not so much to see what no one has yet seen, but to think what nobody has yet thought, about that which everybody sees"

Schrödinger

Happy the men who has been able to know the causes of things.

Virgil, Eclogues, I

I shut my eyes in order to see.

Paul Gauguin

"A man who knows a subject thoroughly, a man so soaked in it that he eats it, sleeps it and dreams it-this man can always teach it with success, no matter how little he knows of technical pedagogy."

H. L. Mencken

"The epigenetic building of a structure is not a creation; it is a revelation"

Chance and Necessity, Jacques Monod

Everything factual is in a sense theory... There is no sense in looking for something behind phenomena: they are theory.

Goethe

"Don't play as if it were a habit. Maybe you've played well, but you can still play badly - it's much easier. Don't ever think you've succeeded. Always try to do better - otherwise drop dead."

Arturo Toscanini

"Dear friend. All theory is gray. And green the golden tree of life."

Goethe

"Then, from these forces, by other propositions, which are also mathematical, we deduce the motions of the planets, the comets, the moon, and the sea. I wish we could derive the rest of the phenomena of nature by the same kind of reasoning from mechanical principles; for I am induced by many reasons to suspect that they may all depend upon forces."

Isaac Newton (1686)

"There can be no true physical science which looks to mathematics for the provision of a conceptual model. Such a procedure is to repeat the errors of the logicians of the Middle Ages."

Alfred North Whitehead

"People have now-a-days got a strange opinion that everything should be taught by lectures. Now, I cannot see that lectures can do so much good as reading the books from which the lectures are taken."

Dr. Johnson (1766)

What can I know?
What ought I to do?
What may I hope?

Kant, The Critique of Pure Reason.

"A professor is one who talks in someone else's sleep."

W. H. Auden

How I need a drink, alcoholic in nature, after the heavy lectures involving quantum mechanics.

(Pi mnemonic)