Rene Descartes (1596-1650) is probably the most important influence on the consciousness soul of the present epoch. Descartes invented analytic geometry, which made the development of the differential and integral calculus possible, and argued forcefully for the existence of the thinking ego, a substance distinct from the body and capable of experience independent of it. The "I am" of Descartes underlies most of our attitudes toward space and time, toward our own bodies and toward one another, insofar as these attitudes acquiesce to the truths of scientific method.

Descartes believed that clear and distinct ideas, particularly geometrical ideas, are the basis for certainty about the existence of objects outside ourselves. Only when an idea of a sense object can be framed in terms of its geometry can we begin to feel that we really know something about it. What is primary for our intuitive knowledge of objects is not their sensory qualities, but the geometrical judgments we can make about them, for these alone are clear, exact and indubitable.

Eurythmy is a method by which we can begin to sense per se the geometrical properties of space and time, of other beings and of our own constitution. Eurythmy, of course, is based on choreographed movements of thought in extended spaces, supplemented by color, light and sculpture. Goethean conversation is a complementary method, by which alike we can sense geometrical properties in one another's thinking and judgment. Goethean conversation is based on free movements and moral impulses within intended spaces, supplemented by a choreography of rules or agreements between natural intelligences.

Both eurythmy and Goethean conversation can help anthroposophists appreciate the ontological significance of thinking as it strives to discover and to meet various objects in the cosmos, largely unknown and mysterious, over which the human being of the future seems destined to exercise a certain discarnate mastery and dominion.