Mutual Quotes - page 17
It sounds rather strange to talk of an infinite universe still expanding. If we were certain that the curvature was negative, we might still, as in the case of positive curvature, replace the phrase "the universe expands" by the equivalent one "the curvature of the universe decreases." But if the curvature is zero, and remains zero throughout, what sort of meaning are we to attach to the "expansion"? The real meaning is, of course, that the mutual distances between the galactic systems, measured in so-called natural measure, increase proportionally to a certain quantity R appearing in the equations, and varying with the time. The interpretation of R as the "radius of curvature" of the universe, though still possible if the universe has a curvature, evidently does not go down to the fundamental meaning of it.
Willem de Sitter
There are many and various particulars, which, by a kind of natural instinct, every one judges to be right, and expects to meet with, from those with, whom he converses. Such as mutual benevolence and respect; a desire of pleasing and obliging each other; and the like. Nothing therefore ought to be said or done, which may by any means discover, that those, whose company we are in, are not much beloved, or, at least, much esteemed by us.
Giovanni della Casa