What is it indeed that gives us the feeling of elegance in a solution, in a demonstration?
Henri PoincareFor a long time the objects that mathematicians dealt with were mostly ill-defined; one believed one knew them, but one represented them with the senses and imagination; but one had but a rough picture and not a precise idea on which reasoning could take hold.
Henri Poincare[T]he different branches of Arithmetic - Ambition [G]eometry is not true, it is advantageous.
Henri PoincareDoubting everything and believing everything are two equally convenient solutions that guard us from having to think
Henri Poincare