Physics is now studying light. The radiant influence of light nourishes life and within human body forms the fabric of consciousness. We are alive and conscious, but our consciousness is immature for we do not yet know the laws that govern our own lives and thoughts. Yet it is certain that light, life, and consciousness are bound together by some undiscovered law. This secret of nature’s alchemy is still hidden from us within our own bodies. By revealing it physics will create a new hope for man. NOTES [1] Whitehead, _Science and the Modern World_. Eddington comes near to the same idea in an essay in _Science, Religion, and Reality_, 1925. See also Weyl, _Was ist Materie?_ 1924, p. 84. It has also been expressed by others quite independently, though I do not know of other published references. [2] E.g. the irreversible motion of an electron in the field of a bar magnet is rendered formally reversible by the assumption that the magnetic field is due to moving electrons. Yet this assumption is highly artificial since it postulates electronic movements that have never been observed. In other cases irreversibility is eliminated by the choice of special co-ordinate systems. Some physicists now hold the view that irreversibility may be inherent in atomic as it is in organic processes. [3] _Internal Constitution of the Stars_, 1926, p. 56. Compare note on p. 44. It may be convenient here to summarize the processes that give at any rate superficial evidence of their irreversibility: processes involving heat changes, or the radiation of light, or mass; the production of energy in a star, the motions of electrons in magnetic fields, certain types of atom-ion collision in mixed gases, processes dependent on retarded potentials, radioactivity, organic growth and evolution, and consciousness itself. Eddington deals only with the case of the emission and absorption of light, but suggests that the direction of time can only be deduced from statistical processes. This is the orthodox view, though it is very doubtful if it is valid now that the quantum processes are receiving formulation. In this connection, see note 4. [4] Einstein. Berlin Akad., _Sitzungsberichte_, 1925, p. 418. But Einstein’s view must be revised in view of recent experimental results (e.g. Harnwell, _Phys. Rev._, vol. 29, 1927, pp. 683 and 831), if these have been correctly interpreted. See Born, _Zeitschr für Physik_, vol. 40, pp. 177-8; and Jordan, _Naturw._ 1927, p. 792.