"Just as we do not perceive that the earth is in motion (to all intents and purposes, it seems to be perfectly still); just as we are unable to apprehend the gradual death of the planet, even though we are convinced of it by scientific arguments; just as we do not perceive the evolution of the species, even though we know that they are changing; just as we perceive matter as still and static, even though its entire molecular structure is in permanent motion; in the same way, we do not perceive the terminality of being in ordinary human behavior, and we see everything as stable and permanent. We see old and deteriorated matter (including aged humans) as always having been that way; we fail to perceive them as becoming, as having deteriorated and become old."