"Riemann has shewn that as there are different kinds of lines and surfaces, so there are different kinds of space of t…"

"I hold in fact (1) That small portions of space are in fact of a nature analogous to little hills on a surface which …"

"No mathematician can give any meaning to the language about matter, force, inertia used in current text-books of mech…"

"We may... be treating merely as physical variations effects which are really due to changes in the curvature of our s…"

"The modern theory of relativity, on its mathematical side, is merely an elaboration of Riemann's analysis."

"It is the reciprocity of these appearances—that each party should think the other has contracted—that is so difficult…"

"...The present revolution of scientific thought follows in natural sequence on the great revolutions at earlier epoch…"

"If you don't take my words too seriously, I would say this: If we assume that all matter would disappear from the wor…"

"Another topic deserving discussion is Einstein’s modification of Newton’s law of gravitation. In spite of all the exc…"

"[T]he program which Immanuel Kant proposed back in the 1760s... was this: our knowledge of the outside world depends …"