Dalembert scientific biography

Thus metaphysics and mathematics are, among all the sciences that belong to reason, those in which imagination has the greatest role. I beg pardon of those delicate spirits who are detractors of mathematics for saying this ....

D'alembert principle

The imagination in a mathematician who creates makes no less difference than in a poet who invents.... Of all the great men of antiquity, Archimedes may be the one who most deserves to be placed beside Homer.

Algebra is generous: she often gives more than is asked for.

Allez en avant, et la foi vous viendra
Push on and faith will catch up with you.
[advice to those who questioned the calculus]

One magnitude is said to be the limit of another magnitude when the second may approach the first within any given magnitude, however small, though the second may never exceed the magnitude it approaches.

Geometry, which should only obey Physics, when united with it sometimes commands it.

If it happens that the question which we wish to