THE TRACK OF EVOLUTION By Professor S. N. PATTEN UNIVERSITY OF PENNSYLVANIA N a recent talk with a friend about the lack of sympathy IN between the workers in physical and social science he asked, "What contribution since that of Malthus has been worthy of consideration?" Malthus, he admitted, helped to arouse the leaders of biologic thought, but who, he asked, had given a definite contribution since that time? The question demands an answer, or at least some discussion of the points involved. It must be admitted that the economists are defective both in their reasoning and in their psychology, but it should also be recognized that there were obstacles to the use of objective measurements in social science which were hard to surmount. Until the pathway is cleared objective measurements, while seeming to add to the clearness of thought, have in reality added to its confusion and furnished more meager results than did a legitimate use of older methods. There have been endeavors to use the method of physical science, but real students have found that beneath the formula taken from mathematics or physics lay hazy ideas and a species of dogmatism that prevented an open-minded consideration of the facts. Every crank, and his name is legion, poses as a scientist and has his formulæ modeled after the latest statement of scientific truth, but this pretense has only been a cloak for ignorance and dogma. If the scientist suspects the economist, the economist in turn suspects the new-comer who trades in the symbols of physical science. Some progress has thus been made even if the results are not so definite as those of physical science. The defects in the social sciences are due to the imperfections in the physical sciences on which they are based. The economist must follow, not precede, the physical scientist? If the economist fails the original fault is not with him, but in the partial development of the sciences on which he depends. Subjective standards have been adhered to because of the lack of objective data. In many fields one has to choose between making physical science and falling back on the loose basis of thought on which the older economic science rested. It is no wonder that under these conditions economics has failed in its main mission and its workers are compelled to endure the sneers of those in more fortunate fields of work. Were I thinking only of making this complaint I would have remained silent. There seems of late some alterations in related sciences raising the hope that a new epoch has come in which the social and physical sciences may cooperate for a common advance. The route to this understanding I shall point out both as to where agreement has been reached and where a gulf still remains. Economic change must be one of a group of changes each of which is an essential step in progressive evolution in order that its conclusions may be put on a par with other contributions. I found that a start could be made in this direction, but no full solution was possible while certain views of physical science persisted. The law of diminishing returns assumes that men have a few stable wants, in the satisfaction of which a keen and destructive struggle arises. The increasing demand for any commodity causes an extension of its production to a point when diminishing returns begin. Men, however, gain relief by changing their wants and thus bringing into use new natural forces. An evolution is thus forced from old objects of consumption to the new, and from objects of which nature is less productive to those of which the yield is more generous. Potatoes and sugar may displace meat and wheat bread. I had little difficulty in proving this point, but the next step was blocked by a supposed physiological principle. It was contended that the cheap food made a low type of man. The rare foods like meat and bread stimulated a higher sort of energy and gave to those who use them a physical and mental superiority that was decisive in every world contest. The Irish potato-eater was doomed to a subordinate position in comparison to the English, who used a more costly food. Economic progress and physical progress were thus put in opposition. This obstacle no longer exists, or at least is in a fair way to be removed. The cheaper foods have of late proved their worth. The vigor coming from the use of meat is in no way superior to that of bread, potatoes, or rice. If but one article or some few articles were used, wheat bread and meat might prove their superiority to the potato or rice; but as the variety of food increases the deficiencies of each sort of cheap food are made up by the excellence of some other food. The cheaper diet as a whole proves its superiority over the old meat and bread diet. The prevailing theory of the past also assumed that to be well-nourished and prosperous led to indulgence, dissipation, and degeneration. The strong, vigorous person was assumed to be he who was somewhat underfed, or at least so poor that overindulgence was impossible. There is a measure of truth in this view, as also there is in the statement that the users of dear food, bread and meat, have been the superior races. By heredity our stomachs are used to coarse food. The primitive man could only occasionally secure the concentrated food the prosperous now use. He faced periods of actual starvation each year, and thus the indulgence of one season had its influence counteracted by the want of another. Our stomach troubles are due to a change to a concentrated diet, a change which was promoted by the belief that the dearer foods gave a superior energy to that derived from cheap foods. The measure of energy is not the quantity of food taken into the stomach, but the quantity of pure blood that results from the digestive process. There are also numerous glands the right action of which is an element in blood values. The best food when eaten too freely may be turned into toxins, and thus be harmful instead of beneficial. This is especially true of meat foods, which are so liable to be transformed into noxious compounds. The word toxin describes the injurious contents of the blood, but we have no term that designates its beneficial contents. We talk in terms of fat, oxygen, protein and carbohydrates, but stop when the peculiar function of each has been described. To supply this gap and to enable me to state my theory in simple terms I shall call all the ingredients of the blood that promote activity "nutrins," and thus make a clear contrast between the nutrins that increase energy and the toxins that depress it. The man improves as the nutrins in the blood increase. High-priced food, indigestion, and toxins represent the elements adverse to the growth of energy, while cheap food, a varied diet, and more nutrins are its upbuilding forces. We can, if we will, study each of these elements by the method of physical science and remedy each defect. Much has been done in all these fields in recent years. The war has forced each nation to solve its food problem, and to make the people's consumption of food harmonize with known facts. "Consciousness," says a recent writer, "is a response to environmental stimuli." The environment excites the nerves, and nerve evokes consciousness. This theory has come down to us from the time of Locke, and is the standard explanation of psychic phenomena. The mind is a blank except as it gets a content through nerve excitation. These nerves are a biological inheritance, a mechanism that has taken ages to develop. By them the external stimuli and the internal response are brought into harmony. Are they the source of this internal response, or do they merely direct a pulse that has an independent origin? Is consciousness a chemical transformation or a biological mechanism? Are its antecedents in the blood or in nerve irritation? The best answer to these questions comes from watching the action of glands and in measuring their influence in creating states of consciousness. The glands accumulate their material and either overflow by the increasing pressure of their content or discharge as the result of nerve stimuli. If it is a self-discharge we dream; if the discharge results from nervous stimuli thought becomes logical and adjustive. The nerves are thus a mechanism not for creating consciousness, but for making thought currents run parallel to external events. They conserve life, but they are not its source. If this explanation is correct the antecedent to consciousness is a gland discharge creating a pulse that becomes thought through the nerve mechanisms turning the pulse into motor power. The content of a gland is like the steam in a boiler, which by itself merely has explosive power, but which by the mechanisms of the engine is transformed into a steady working force. Nerve development, like improvements in the engine, increases adjustment as the engine creates force, but in neither case are they the seat of the ultimate power. No explanation of movement is possible in terms of engines or nerves. This is readily seen in the case of an engine. Is it not equally true of nerves? Bear in mind that this is not an attempt to explain consciousness without nerves, but an endeavor to show that explanations of consciousness merely in terms of nerves is doomed to failure. Such explanations lack the true starting point and hence fail to connect consciousness with its chemical antecedents in the blood. From blood to gland, from gland to pulse, and from pulse to nerve reaction is the series through which our life processes go. The pulse in terms of consciousness is emotion; nerve excitation becomes ideas. When the two blend we have the higher life for which we yearn. Each pulse starts as emotion and is transformed into clear thought as the various nerve reactions determine the channel in which it moves. If this be true, dreams and wishes represent the early stages of thought movement when the emotional pulse is dominant. The clue to their origin lies in emotions that are non-adjustive, and not in the useful reactions which harmonize life with its environment. We must start with the glands and connect them with dreams and wishes. If sex discharges result in sex dreams we have a ready VOL. V.-23. means of connecting gland activity with conscious emotion. Even if it be admitted that some dreams are not sex dreams they undoubtedly are the most elementary of our dreams. Here plainly a discharge antedates consciousness and colors its content. The philosopher Kant claimed that space and time were subjective forms, and thus the ultimates of thought. It would be nearer the truth to say that sex images are thought's ultimates. The pulse starts in a movement towards sex images, and would end there if our inherited nerve mechanisms did not censor the pulse and force it in other directions. Conscious thought has a foundation in sex but a superstructure of sense impressions. The external elements are magnified because of their usefulness, while the internal are distorted or suppressed. It is worth asking how perfect these sex images would be if no sense impressions came from the outside to make them definite and clear. Our dreams are not purely subjective. Suppose a healthy child should grow up with no sensory nerves to bring in external impressions, but with perfect gland activity and a well-developed sympathetic nerve system, what pictures would accompany its sex discharges? How far could it go towards creating definite images? What this child could do would show the pulse forms as contrasted to the content due to sense impressions. We thus come to a problem akin to that of Kant. Thought would be a combination of pulse forms and sense data, but these forms would not be transcendental in origin, but the result of sex evolution. Each clear thought would be partly pulse and partly sense; the vital element would be in the one, the utility in the other. The elements of the dream are beneath our waking thought, but its sense content is so fully overlaid that the dream element is confused with the inflowing sense impressions. Though censored and depleted, the dream form exists and is the vital antecedent in all our thought. The nerves dominate, but they do not originate. This view involves a type of thinking that is old, for it assumes there are native elements in mental activity not derived from the senses. Instead of a blank mind there are inherited mechanisms which determine the types of thinking. But these forms are not transcendental, nor do they need external stimuli to excite their activity. The forms of thought are independent of and antecedent to the concrete additions that come from sensory sources. The new view differs from the old in not starting from abstract concepts like space and time, but from concrete images due to sex and fear. Both sex and fear images are evoked by internal awakenings and not by external data. Here are origins of thought that heredity could create, and if they |