Steiner's reading of Western philosophy as four roughly seven-to-eight-century epochs in which the soul's experience of thinking slowly matures.
The Evolution of Thought-Life is the historical thesis Rudolf Steiner sets out in The Riddles of Philosophy, that the thinking of the West has passed through distinct ages. Each age, he argues, is moved by an objective spiritual impulse working beneath outer events, and each carries the human soul one stage further in its experience of pure thought, from Greek antiquity toward the self-conscious soul of the present.
In Steiner's Own Words
The first epoch of the development of philosophical views begins in Greek antiquity. It can be distinctly traced back as far as Pherekydes of Syros and Thales of Miletos and it comes to a close in the age of beginning Christianity. The spiritual aspiration of mankind in this age shows an essentially different character from that of earlier times. It is the age of awakening thought life. Prior to this age, the human soul lived in imaginative (symbolic) thought pictures that expressed its relation to the world and existence. All attempts to find the philosophical thought life developed in pre-Greek times fail upon closer inspection. Genuine philosophy cannot be dated earlier than the Greek civilization.
What it Means Today
The clearest modern continuation of this thesis is the work of Owen Barfield, the British solicitor and philologist who belonged to the Inklings circle alongside C. S. Lewis and J. R. R. Tolkien and who read Steiner closely for more than fifty years. In Saving the Appearances: A Study in Idolatry (Wesleyan University Press, 1957), Barfield argued, on linguistic rather than occult evidence, that human consciousness itself has a history, and that the way the Greeks experienced a word or a thought differed in kind from the way a modern reader does. Tracing the drift of word meanings across centuries, he reached a conclusion close to Steiner's: that thinking has not stood still but evolved, moving from a participatory awareness, in which the knower felt joined to the world, toward the detached, spectator stance of modern science. Barfield called this long arc the evolution of consciousness, and Steiner's four-epoch scheme in GA 18 is one of its earliest detailed maps.
What makes Steiner's account distinct from a standard history of ideas is the claim in his guiding thoughts that the epochs are driven by impulses independent of the individual thinkers in whom they appear, much as a species follows a law of its own. Thalira synthesis: read this way, the history of philosophy becomes a biography of the soul, and reading Plato, Descartes, or Kant is less a survey of opinions than a record of how human thinking learned, stage by stage, to stand on its own ground.
Where to Read More