I did not invent these, just collected it

Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.

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"A mathematician is a device for turning coffee into theorems" (P. Erdos)

Addendum: American coffee is good for lemmas.

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An engineer thinks that his equations are an approximation to reality. A physicist thinks reality is an approximation to his equations. A mathematician doesn't care.

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Old mathematicians never die; they just lose some of their functions.

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Mathematicians are like Frenchmen: whatever you say to them, they translate it into their own language, and forthwith it means something entirely different. -- Goethe

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Mathematics is the art of giving the same name to different things. -- J. H. Poincare

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What is a rigorous definition of rigor?

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There is no logical foundation of mathematics, and Gödel has proved it!

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I do not think -- therefore I am not.

Here is the illustration of this principle:

One evening Rene Descartes went to relax at a local tavern. The tender approached and said, "Ah, good evening Monsieur Descartes! Shall I serve you the usual drink?". Descartes replied, "I think not.", and promptly vanished.

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A topologist is a person who doesn't know the difference between a coffee cup and a doughnut.

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A mathematician is a blind man in a dark room looking for a black cat which isn't there. (Charles R Darwin)

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A statistician is someone who is good with numbers but lacks the personality to be an accountant.

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Classification of mathematical problems as linear and nonlinear is like classification of the Universe as bananas and non-bananas.

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A law of conservation of difficulties: there is no easy way to prove a deep result.

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A tragedy of mathematics is a beautiful conjecture ruined by an ugly fact.

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Algebraic symbols are used when you do not know what you are talking about.

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Philosophy is a game with objectives and no rules.

Mathematics is a game with rules and no objectives.

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Math is like love; a simple idea, but it can get complicated.

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"

- David O. McKay