Carl Gustav Jacob Jacobi quotes

Carl Gustav Jacob Jacobi was a German mathematician acclaimed for his contributions to elliptic functions and differential equations. His work significantly advanced the field of mathematics in the 19th century. He is remembered as one of the most influential mathematicians of his era. Here are 3 of his quotes:

Wherever Mathematics is mixed up with anything, which is outside its field, you will find attempts to demonstrate these merely conventional propositions a priori, and it will be your task to find out the false deduction in each case. (Carl Gustav Jacob Jacobi)
Any progress in the theory of partial differential equations must also bring about a progress in Mechanics. View quote
Carl Gustav Jacob Jacobi
It is true that M. Fourier had the opinion that the principal end of mathematics was the public utility and the explanation of natural phenomena; but such a philosopher as he is should have known that the unique end of science is the honor of the human mind, and that from this point of view a question of number is as important as a question of the system of the world. View quote
Carl Gustav Jacob Jacobi