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

"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…"

"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."

"In reality, the law always contains less than the fact itself, because it does not reproduce the fact as a whole but …"

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