A civilization can, indeed, advance and decline at the same time. Eric Voegelin, New Science of Politics, 132.
As civilization advances, the sense of wonder declines. Abraham Heschel, God in Search of Man
Modern civilization is gnostic civilization. Gnostic civilization is left-hemispheric civilization.
Gnosis: Knowledge. Specifically, explicit knowledge, the kind of knowledge that lets us understand, use, and control . . . abilities the left hemisphere values (because they underwrite its primary (predatory) function that allows us to survive in the first place).
The Summit of Western Civilization
When, on December 6, 1273, Aquinas tossed aside his Summa and said everything he had written was straw, western civilization entered its long decline.
I'd argue that Aquinas' mind had stretched the left hemisphere until it snapped, leaving Aquinas with the right hemisphere's appreciation of the Tao: the ineffable, the unknowable, the Thing that Cannot be Articulated.
He had, in other words, stretched the left hemisphere to its proper limits. When it went as far as it could and snapped, Aquinas was fine with that. He tossed aside his words (tools of the left hemisphere).
Philosophy entered a long decline from which it didn't start to recover until, I'd say, around 1900, when James, Bergson, Whitehead, and other (effectively) post-modernist thinkers started pushing back against modern (Cartesian-Baconian) philosophy.
Modernity is civilization in advance and decline at the same time: Advancing in material things; declining in the immaterial.
Knowledge rising; awe falling.
