In my opinion the individual argument renders the monistic conception of mind and matter unassailable. The food that we may eat and the water we may drink are dead, and as such they display absolutely no evidence of nervous or mental processes. When they enter our bodies, they with other foods replenish the various tissues, and among these the parts of the brain. In a material sense they become actual living protoplasm, replacing the worn-out substances destroyed during our previous thinking; and their properties are combined to make brain and thought, to play for a time their part in life, and to pass back into the world of dead, unthinking things. Every one of us knows that hunger reduces our ability to think clearly and fully, and every one knows also that mental vigor is renewed when fresh supplies of nourishment reach the brain. What can be the source of mentality, if it is not something brought in from the outer world along with the chemical substances which taken singly are devoid of mind? Scientific monism frankly replies that it is unable to find another origin. We are thus brought to recognize, not only the continuity taught by organic evolution, but also the uniformity of the materials constituting the entire sensible world, inasmuch as the ultimate unit of all nervous phenomena is the reflex act of a protoplasmic mass, which itself is a synthesis of properties inhering in the chemical elements making up living matter. Among inorganic things the mind-stuff units are combined in relatively simple ways, and the "stuff" does not give any outward evidences of "mind" as such. Living things are almost infinitely complex as regards their chemical organization, and even in the very lowest of them we can discern a cell-reflex element which, combined with others like it, forms the unit of the compounds we call instinct, intelligence, and reason. Hence through an analysis of mental evolution we are enabled to form the larger conception of a continuous universe whose ultimate elements are the same everywhere. VII SOCIAL EVOLUTION AS A BIOLOGICAL PROCESS