Whether you think that you can, or that you can’t, you are usually right. (Henry Ford)

Each problem that I solved became a rule which served afterwards to solve other problems. (Rene Descartes, Discours de la Methode)

Not everything that can be counted counts, and not everything that counts can be counted. (Albert Einstein)

It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. (Carl Sagan)