Abert Einstein.
What we know is a drop, what we don't know is an ocean.
Sir Isaac Newton.
If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.
John von Neumann.
The more you know, the more you know you don't know.
Aristotle.
Mathematics is the tool specially suited for dealing with abstract concepts of any kind and there is no limit to its power in this field.
Paul Dirac.
The essence of mathematics is not to make simple things complicated, but to make complicated things simple.
S. Gudder