Arithmetic is where numbers fly like pigeons in and out of your head. – Carl Sandburg, "Arithmetic"

One of the endlessly alluring aspects of mathematics is that its thorniest paradoxes have a way of blooming into beautiful theories. – Philip J. Davis

Nature does not count nor do integers occur in nature. Man made them all, integers and all the rest, Kronecker to the contrary notwithstanding. – Percy William Bridgman, The Way Things Are