History in the strict sense is very short in evolutionary terms, and as a consequence all the texts to which we have access are product of organisms little different if at all from ourselves. This consistency over a period of time which seems to us long, since it is a large multiple of an average human life span, has led to or strongly reinforced the belief that some part of ourselves stands above temporal accident and biological form or their interaction. To dualists, this is the soul; those inclined to physicalism call it human nature. However, Heraclitus is right, panta rei, and both are errors.

This misprision could fade if the species persists long enough to hold records covering a period long enough for evolutionary change to occur. Where at present we may empathize with an author without very much difficulty, merely running their ideas in our heads to produce a rough, ready, and effective appreciation of their position, readers in the future may be reviewing the statements of ancestors with markedly different physical structures, brain configurations, and even breeding programs. Even assuming a continuous tradition of scholarship between these two organisms, the difficulties standing in the way of understanding will be enormous, perhaps much resembling those standing between us and the other apes.