The Theory of Heat; Second Scientific Course;
14 lectures, Stuttgart, March 1-14, 1920 (CW 321)

Following his first scientific course the previous year (The Light Course), in these lectures Rudolf Steiner discusses the nature of warmth, its relationship to the four states of matter, to light, to color, and to the subearthly and superearthly realms. He extends the modern ideas of physics through aspects of understanding achieved by spiritual science. With extensive notes and diagrams, this work comprises essential reference material for natural science teachers, as well as interested parents and anyone wanting a deeper understanding of a theory of heat and warmth based on spiriual science.

"The manifold new aspects of the subject presented placed the element of warmth within the great evolution of the cosmos and then traced it even into the phenomena of life, the concrete processes in the transformation of the states of aggregation in matter, and even into mathematical formulae.... Indications thus given were then worked out during the following years in the Research Institute and Laboratory at the Goetheanum and traced into numerous phenomena of the rhythms of the day and the year, phenomena of life, the most subtle influences in processes of crystallization, and they became useful in the later inaugurated agricultural work." --Guenther Wachsmuth, The Life and Work of Rudolf Steiner (p. 378)

This volume is a translation from German of Geisteswissenschaftliche Impulse II zur Entwickelung der Physik II: Zweiter naturwissenschaftlicher Kurs: Die Wärme auf der Grenze positiver und negativer Materialität (GA 321).