In the Warmth Course, Rudolf Steiner approaches an understanding of the nature of heat, something that amongst modern physicists is only described in regard to matter as particle motion (i.e. microscopic agitation of molecules) and in regard to energy as the infra-red region of the electromagnetic spectrum. It is conventionally held that the infra-red wavelengths agitate particles into motion and these then also emit infra-red in their excited state, and that whichever aspect you are describing, heat is just another attribute of the physical universe which can be quantified like mass or velocity.

Steiner approaches the matter with the aid of a series of physics experiments – actually carried out during the lectures – in order to examine the behaviour of various substances and devices when subjected to heat as well as to spectral light. Fully cognizant of, and with specific references to, the work and theories of physicists of the day – Helmholtz, Mach, Planck, and others – he examines the behaviour and idiosyncrasies of heat and arrives at views which though not easy to grasp, do make sense; and which serve to explain much about the nature of not only material reality but also the entrance into spiritual reality. Heat is seen to manifest in its effects in spatial reality but in its own being is non-spatial. It stands at the border between the spatial and non-spatial (the realm of the spiritual or consciousness) and partakes of both. In heat, both the material (spatial) and the spiritual (non-spatial) interplay. It is not simply a state where matter and energy meet, but a state where matter and consciousness, albeit of a simple elemental nature, meet.

Science only acknowledges the quantitative universe as a dead, mechanical and purposeless arrangement of matter and energy in the mysterious background of space and time. The consciousness of the scientist (and of all humanity) who observes the universe are not taken into consideration except as an evolutionary by-product of this dead, unconscious universe. How the qualitative element of conscious awareness somehow emerged out of a purely quantitative universe – i.e. containing only mass, velocity, electric charge, gravitational force, etc. – cannot be logically supported, as the assertion of the latter precludes the possibility of the former. Steiner’s view, on the other hand, offers a spectrum which bridges over from the quantitative by degrees to the qualitative. The material states of solid, liquid and gas, and then heat and light, are just the outwardly visible portion of the spectrum. Below the solid there is a sub-physical realm which extends “downward” into the spiritual; while in the other direction, beyond heat (and even within heat), ponderous matter disappears and elements of spirit (consciousness) begin. What is more – and even more astounding – is that the spiritual ends of this seemingly linear spectrum, though outwardly invisible, meet to form a “circular” continuum and the place where they meet is in the human being, who is seen as a segment of this spectrum through the aspects of human thinking, feeling and will. Thus the human being stands within the full spectrum of universal nature in such a way that he confronts outer nature and can also comprehend himself within the totality of world existence.

Studying these lectures and also bringing their content into relationship with other lectures where Steiner describes the seven elemental states should provide a powerful and enlightening stimulus for those who have pondered the mysteries of matter and consciousness within the anthroposophical perspective.