If we knew exactly the laws of nature and the situation of the universe at the initial moment, we could predict exactly the situation of the same universe at a succeeding moment.
Thus, they are free to replace some objects by others so long as the relations remain unchanged.
Ideas rose in clouds; I felt them collide until pairs interlocked, so to speak, making a stable combination.
Mathematicians are born, not made.
Mathematicians do not study objects, but relations between objects.
A scientist worthy of his name, about all a mathematician, experiences in his work the same impression as an artist; his pleasure is as great and of the same nature.
