"The student of mathematics often finds it hard to throw off the uncomfortable feeling that his science, in the person…"

"The mental operation by which one achieves new concepts and which one denotes generally by the inadequate name of ind…"

"Nature consists of the elements given by the senses. Primitive man first takes out of them certain complexes of these…"

"Thought-economy is most highly developed in mathematics, that science which has reached the highest formal developmen…"

"I know of nothing more terrible than the poor creatures who have learned too much. Instead of the sound powerful judg…"

"Personally, people know themselves very poorly."

"There is no problem in all mathematics that cannot be solved by direct counting. But with the present implements of m…"

"I see the expression of... economy clearly in the gradual reduction of the statical laws of machines to a single one,…"

"Not bodies produce sensations, but element-complexes (sensation-complexes) constitute the bodies. When the physicist …"

"The aim of research is the discovery of the equations which subsist between the elements of phenomena."