"Myth is already enlightenment, and enlightenment reverts to mythology."
Adorno, T. W., and Max Horkheimer. [1947] 2002. Dialectic of Enlightenment, translated by E. Jephcott. Stanford: Stanford University Press.
Rational thought in western philosophy is closely related to 'Gnothi seauton'
https://en.wikipedia.org/wiki/Know_thyself
With science, as the foremost form of rationality today, of the opinion, the 'self' residing in the brain. Which may be an albeit practical myth of the brain to explain itself to itself.