S … … +s3+s2+s1+ (s) + s1+s11+ … …
||—————————————————
P … … +p4+p3+p2+p1+(p)+p1+p11+p111+p1111+. … .
Each link of the psychic process has some link of the physical process as its concomitant.
s has p, s1―p1, s2―p2, s1―p1, s11―p11.
The psychic process not having its links causally connected, the causal necessity can only be followed along its concomitant physical or physiological series. Hence we can see why the physiological series is indispensable to the psychic series.
The finiteness of the psychic process makes it impossible to apply to it the principle of necessity. For while a physical process must necessarily have a physical antecedent and physical consequent, a psychic process and each link of it does not necessarily have an antecedent or consequent, it may begin and end at any link.
It is only by means of the physical or physiological series that the principles of continuity and necessary causal connection, the foundation of all objective science, can be worked in psychology. Without the help of the concomitant physiological series the investigator of the psychic process is, scientifically considered, completely helpless, since the psychic process has no objectively necessary causal interconnection.
The "Voluntaristic" school in attempting to make of psychology a science independent of all physiology is fundamentally wrong. Without the physiological series psychology has no cement to fasten its material with, it has no foundation to build on. Psychology can maintain itself in the work of objective natural sciences only on condition of its intimate interdependence with physiology. No psychology without physiology. The psycho-physiological hypothesis is both inductively and deductively the sine qua non of the science of psychology.
XIV Life and the Psychic Process
We have pointed out that the psychic process is essentially finite and final, can we find any other process that should be characterized by the same mark of finiteness and finality? We find an analogous process in life. The life process is one that has the aspect of finiteness. Ontogenetically, the life-process of an organism has its beginning in the fertilization or stimulation to life-activity of the ovum, and has its end in death. Phylogenetically, the life process runs a determinate course. There was a time when geological conditions did not permit the presence of life, and there will come a time when life will be extinct. Ontogenetically, the biological process is analogous to the mental process. The biological process, unlike the physical process, is not endless; it has a definite beginning and end. Taking any stage of the process as the starting point, we find that neither the chain of antecedents, nor that of consequents can be followed endlessly. Being a finite process we find in it the same relation we discovered in the psychic process,―the first term of the series has no antecedent and the last one has no consequent. Furthermore, the biological process, like the psychological one, may be cut short at any stage,―the organism or the protoplasm may die or be killed. It is only mechanically regarded that the biological process can be worked into the definite texture of physical series.
The finiteness of the life process is especially manifested from the point of finality. In examining the character of living beings, in contradistinction to physical things, we find a fundamental difference between the two. The structure and function of living beings can be regarded under the concept of purpose or that of final causation, the purpose being the good, the advantage, the utility of the organism. Inanimate things cannot be regarded under the concept of final causation, but under that of efficient causation. The stone lying yonder has no purpose, it has no special advantage for its material particles from its particular position. The inner relations of its parts and the relations of its surface-angles and prominences are not of any ultimate good to the stone, nor do we ask of what use is this particular vibration to the molecules. We do ask, however, this question of utility in regard to organisms. Of what use is the grazing or drinking to the cow? Of what use is this particular organ and its function to this or that organism? The problem of utility is one that can only be raised in the case of organic life, but not in the case of inorganic things. We can see the reason why it should be so. Life may be regarded as an adaptation of inner and outer relations. Adaptation and fitness are important criteria with biological processes. What is the fitness, or utility of organs and their functions to the particular organism, and how have they come to this given state of fitness? These problems cannot be ignored by biology as a science. The whole of the Darwinian theory aims to give the key to the way the different forms of adaptations have come about. Adaptation and utility, however, mean aims. A biological process is not an endless series of antecedents and consequents, but one that has an end. A life process is a final process taking place in the organism in its internal and essential adjustments.
The finality of the life process is clearly brought out, if looked at from a totally different point of view. The most characteristic feature of a living organism, is its being an organic whole, a unity, an individuality. All the parts of the organism bear relation to and have their significance with regard to the organism as a whole. The fin of the fish, the wing of the bird, and the arm of the man cease to be what they are, if separated from the particular individual to which they respectively belong. The structure and function of the part can be understood only in relation to the needs of the organic whole. The parts of the individual subserve the organic unity. In the course of evolution, both ontogenetic and phylogenetic, parts may arise or drop out for the benefit and advantage of the whole. Mechanically considered, an organism is nothing but a heap of vibrating molecules or atoms; biologically regarded, this heap constitutes a whole, an individual, and each vibration is for the good of this whole, if the individual is to maintain itself in existence.
It may be objected that a machine, though purely mechanical, may be similarly defined. A machine constitutes a whole, a unity, and every part bears a definite relation to the whole, and cannot In fact be understood without the knowledge of the machine as a whole. Who, without knowing a watch as a whole, could have guessed the function of a particular wheel or spring, if shown by itself? Each part within a mechanism has its distinctive character only in relation to the other parts forming an interrelated system. Should this be granted, in what sense, then, it may be asked, does an organism differ from a mechanism? Must not then a biological process be, after all, reduced to mechanical terms; and if this be so, is not rather the opposite statement the correct one, namely, that a biological process does not really differ from a physical process? This, however, is not so. The difference between the two is a fundamental one. The unity of the mechanism does not lie in the machine per se, but in the needs and mind of the mechanician, while the organic unity is postulated as being in the organism itself. The purpose of the machine does not lie in the machine itself, but in needs outside itself; no machine exists, for its own advantage and good, from its very nature a machine is for something else.
An organism, on the contrary, constitutes its own purpose. No organism in nature, not as yet modified by artificial selection, exists entirely for the good of another. The structure and functions of the parts of an organism are for the good and advantage of that particular individual. Unlike a machine, the purpose falls not outside, but inside the organism. An organism forms a closed circle, a microcosm, to which the macrocosm is made subservient. Each organism is a centre from which rays radiate to all the points of the universe; in other words, an organism is an end for which everything else is nothing but a means. Darwin was so much impressed with this teleological aspect of organic life that he frankly admitted that, if only one example in a natural state could be produced, an example of an organism showing structure and function useful not to itself, but to another organism, his whole theory of evolution