The General Nature of Physical Reality

In the first place, we must establish the notion of the organism--animal or human--as a purely physical mechanism, having a nature which renders it quite incapable of combining with any psychological entities or processes. Now, the average reader--even if he is a professional psychologist or physicist (unless he is both, and at the same time a philosopher)--may well fail to gather the full import of this statement; so that it becomes necessary to dilate to some extent upon the exact nature of physical being.

When we use the word, physical, we shall refer to something which is made up exclusively of units which the modern theoretical physicist regards as forming the foundation stones of the universe, and which is governed only by the elementary laws which the physicist conceives as applying to such units or their combinations. The layman thinks of the physical world in terms of hard and soft, colors and shades, sounds and smells, etc., but the modern physicist knows that these concepts are really psychological or, at any rate, are only symbols for the things with which his own thought is concerned. His world is made up of elecical particles arranged into geometrical, dynamic patterns, in physical space and time. Of these ultimate particles, there seem to be only two different kinds, namely, the electron and the proton, which appear to exist in about equal numbers in the universe. By virtue of their forces of electrical attraction, electrons and protons combine with one another to form a vast variety of very complex structures, which are capable of being described exclusively in geometrical and electromagnetic terms. These structures can be arranged into a hierarchy which, in increasing order of complexity, may be sketched as follows.

The electrons and protons combine, firstly, to generate a series of atoms which range from very simple to quite complicated forms, and which correspond approximately with the table of chemical elements. Each neutral atom contains an equal number of protons and electrons, but there are, nevertheless, residual electrical forces which make it possible for atoms to adhere to one another and thus to produce still more complex structures, known as molecules. The molecules correspond with compound chemical substances, of which there is a much wider variety than there is of chemical elements. Molecules and atoms are both supposed to be so small as to be entirely invisible, even when using the most high-powered of microscopes. However, molecules can combine with one another by a process which does not differ essentially from the one by which they, themselves, are formed--to yield particles or structures which may be visible even to the naked eye. The smallest of these are known as "colloidal particles," whereas larger ones constitute crystals. A still further aggregation of molecular, colloidal, or crystalline units gives rise to the inorganic and organic bodies with which we are most familiar in everyday life.

The distinction between animate and inanimate bodies, which corresponds to that between the organic and the inorganic, appears to the unscientific mind to involve a fundamental difference of kind. This persuasion is apparently due primarily to the seemingly spontaneous activities which are exhibited by organisms, whereas inorganic objects usually move only under the influence of an external force. It is also supported by the knowledge that in the case of our own organisms, the activity is closely correlated with certain psychological phenomena which seem to be its causes. However, since these psychological phenomena lie outside of the domain of physical investigation they cannot be regarded as furnishing really pertinent evidence, and we are without proof that psychical factors do not also accompany the existence and inactivity of inorganic bodies. Of course, the common sense conviction as to the uniqueness of living beings finds representation in certain quasi-scientific doctrines, which are called "vitalistic"; but by far the great majority of scientific thinkers resolutely reject these notions. They believe that the distinction between the organic and the inorganic is one of structure rather than of fundamental nature. The ultimate stuff and laws of the two classes of bodies are regarded as identical.