The essence of mathematics lies in its freedom. - Cantor

When you can measure what you are talking about and express it in numbers, you are truly You have some understanding of it; but when you cannot measure it or express it in numbers, your understanding is superficial and unsatisfactory. This understanding may be the beginning of cognition, but in terms of thinking, it is difficult to say that it has entered the stage of science. ——Lord Kelvin

Mathematics is the gymnastics of the mind.