It Is With Logic That One Proves;

Later Generations Will Regard Mengenlehre (set Theory) As A Disease From Which One Has Recovered.

Mathematics Is The Art Of Giving The Same Name To Different Things. [as Opposed To The Quotation: Poetry Is The Art Of Giving Different Names To The Same Thing].

But All Of My Efforts Served Only To Make Me Better Acquainted With The Difficulty, Which In Itself Was Something.

Mathematics Has A Threefold Purpose. It Must Provide An Instrument For The Study Of Nature. But This Is Not All: It Has A Philosophical Purpose, And, I Daresay, An Aesthetic Purpose.

A Reality Completely Independent Of The Spirit That Conceives It, Sees It, Or Feels It, Is An Impossibility. A World So External As That, Even If It Existed, Would Be Forever Inaccessible To Us.