He explains this deterioration as primarily caused by a degeneration of the race, due to laxity and errors in the State regulation of marriages, and the consequent birth of biologically inferior individuals.
The theories of Plato are only the most illustrious example of the tendency characteristic of Greek philosophical thinkers to idealise the immutable as possessing a higher value than that which varies.

This affected all their social speculations.

They believed in the ideal of an absolute order in society, from which, when it is once established, any deviation must be for the worse.

Aristotle, considering the subject from a practical point of view, laid down that changes in an established social order are undesirable, and should be as few and slight as possible.

[Footnote: Politics, ii.