“It is quite possible we may have formed entirely erroneous ideas of what we actually see. The greenish gray patches may not be seas at all, nor the ruddy continents, solid land. Neither may the obscuring patches be clouds of vapor.”
“My ideas about time all developed from the realization that if nothing were to change we could not say that time passes. Change is primary, time, if it exists at all, is something we deduce from it.”