It would appear that among scientific men discussion of the general principles of natural science has, on the whole, proved more congenial to mathematicians and physicists than to biologists. Just why this should be so might be difficult to explain or justify. But one reason seems to lie in the comparative ambiguity of the concept of causation in biology. In general, the term causation has been used in science to designate the special rôle of active factors, rather than of passive (...) or stable factors, in the determination of single events. By active factors we mean those which involve physical change, typically associated with transfer of energy; these are distinguished from stable factors or invariants which persist unchanged throughout the process under consideration. Thus in the classical isolated system, the total energy represents a stable factor which remains the same through all transformations of the system. The energy changes its form, potential or distribution, but not its total quantity. This rule of conservation defines a static condition persisting as a limiting factor through any case of change. Similarly, the permanent or unchanging factor in a machine consists in the stable properties and structural interconnections of its parts; together those constitute an invariant which fixes definitely the possible range of activity. Activity itself requires flow of energy; strictly speaking, a causal factor is not a static factor but is a change of some kind; releasing events are included under causal events since they introduce factors without which change does not occur. (shrink)

In considering this problem a distinction should first be made between its scientific and it philosophical aspects. The scientific problem is that of defining in exact understandable terms those conditions and factors which make possible the synthesis of the living organism from the simpler elements of the non-living environment, and also its maintenance in the adult state as a fully developed and autonomous organic individual. The problem as thus stated is one to be approached by methods of observation and experiment, (...) leading to verifiable results which are then expressed in systematic and intelligible form. The final statements or representations thus reached, the accepted scientific generalizations, inevitably take on a theoretical form, and as such are necessarily partial and abstract. Many of them, in fact, are to be regarded primarily as simplifications or models devised in the interest of clear representation or understanding. Their relation to concrete reality may range from attempts at exact portraiture to formulæ or diagrams having little more than heuristic significance. Any realistic philosophy of nature must always remember how incomplete and provisional are the theoretical conceptions of any natural science. (shrink)

In my recent paper on Living Systems and Non-living Systems I considered briefly the question of the special rôle assignable to the psychic, as natural factor associated with yet different from the physical, in the activities of living organisms. The general conclusion was reached that this rôle is primarily integrative, in correspondence with the integrative character which is the essential distinguishing feature of the psychic in our experience. As integrative, the psychic factor has a special relation to the synthetic activity (...) so highly developed in living organism, since synthesis is by its nature integration or whole-formation. Originative or novelty-producing activity is the special prerogative of the psychic, rather than simple repetition or routine; the latter, as exemplifying the stable or conservative side of nature, belongs in the field of the physical. According to this conception, the psychic is the source of initiative when action takes on a novel or creative form, as in conscious voluntary activity or in natural creative action in general. For example, in animals vegetative or routine processes may be purely physiological and unconscious, while actions requiring special initiative or innovation demand conscious effort and attention. (shrink)

When we consider closely any highly integrated vital process, like embryonic development, or animal behavior of the end-subserving or purposive type, we are inevitably impressed with the importance of those special controlling factors, collectively termed “regulative,” which appear chiefly responsible for the unified and finalistic character of the whole sequence of events. These factors are persistent in their influence although they may act intermittently. Without their presence the sequence would soon lose coördination and “run wild,” just as an automobile runs (...) off the road unless occasional compensating touches are given to the steering wheel. They are the factors which give unity and direction to the total process. Generalizing, we may say that in any complex unified process, especially a synthetic one—where the progress is from less to greater complexity—integration seems always to imply or presuppose the operation of regulative factors having the character which we call directive. These keep the sequence of events to a definite course which in the living organism usually terminates in some outcome having special biological significance, or survival value. (shrink)

The candid student of scientific method will recognize that biology is not entirely a physical science, while acknowledging that it owes its present state of development largely or mainly to physical conceptions and methods. It is clear that the constant features of vital organization and activity presuppose the physical constancies as basis. Nevertheless the living organism has proved in many ways refractory to a purely physical analysis. This is not merely because the higher organisms have their psychical side and that (...) psychological method differs from physical method; conceivably a properly unified science might apply equally to the physical and the psychical sides of nature. Nor is it entirely because vital behaviour is more individualized and less predictable than physical behaviour. It is rather that certain fundamental features of natural process, largely neglected by physics, are just those which are of chief importance in those flux-like entities which are living organisms. The traditional methods of physics, which analyze nature into combinations of invariant elements and processes, are ill-adapted to deal with the fluid, asymmetrical and largely indeterminate features of process as displayed so conspicuously in living organisms. This, put briefly, is the contention of L. L. Whyte, physicist and author of the recent remarkable book on the relations between physics and biology. In the present paper I propose first to consider especially those sections of the book which bear more particularly on the fundamental problems of biology; this part is paraphrase and commentary rather than summary, although never departing far from the subject of unitary principle as defined by Whyte. Later I shall consider some philosophical implications which seem important. For the details of Whyte's exposition the reader should refer to his book, which is notably clear, concise and critical in style and treatment, as well as comprehensive and fully realistic in its point of view. (shrink)

Biology is in a unique position among the natural sciences. It is not simply complex physics and chemistry, for living organisms have a psychological as well as a physical side. Even as physical systems their character is highly special, largely because their material substance is continually changing; perhaps it was from them that Heraclitus derived his idea that all is flow. The comparison with vortexes and candle flames is an old one. Wilhelm Ostwald included living organisms in his class of (...) “stationary systems”: they represent not a static but a kinetic equilibrium, what we now often call a “steady state”; there is a balance of constitutive and dissipative processes. Materials and energy converge to the living center, undergo there characteristic transformations, among which complex chemical and structural syntheses are conspicuous, and are again distributed at random to the surroundings. The living organism is thus the seat of a special type of physical and chemical activity found nowhere else in nature, and it is significant that this is associated with psychical activity—demonstrably in the higher organisms, by implication in the lower. (shrink)

A theory in natural science is a comprehensive formula or doctrine which describes and correlates in a unified abstract form of statement the general determining factors of some special group of natural facts. It is at once inclusive, realistic and understandable. If a theoretical statement holds good, the existence and characteristics of many individual events can be inferred deductively from it. It thus gives a logical basis for empirical fact. But it is based on experience of nature, and must conform (...) to the facts of nature; these are primary, and a valid theory, no matter how broad it may be, is to be considered as itself a statement of fact, i.e., a true description of some condition which has a real and stable existence in the natural world. In its scientific usage, the term “fact” refers primarily to some datum of experience having the special character of permanence or regular recurrence; this is why scientific facts are verifiable; in this respect they differ from the passing individual events of history. Any scientific theory presupposes the stability and unequivocality of the natural facts. Hence if a theory is sound, it furnishes a reliable basis for prediction, discovery and invention. Scientific or technological creation then becomes possible; modern engineering and medicine could never have become what they are without a background of theoretical physics and biology. Obviously any natural science must always have at its disposal an ample body of observational and experimental data, but in most cases the work of collecting and verifying these is carried out under the guidance of theory. (shrink)

The problem of synthesis in biology may have reference to the evolutionary origin of living organisms in past time, a process not directly observable but conceivably reconstructible in broad outline: thus to the biochemist this evolution may appear as the evolution of the special biological compounds, to the psychologist as the evolution of “mind”—or at least of types of behavior. Or the problem may refer to the synthesis of the individual animal or plant, a process of construction which typically starts (...) from a detached portion of a parent organism, such as an egg or seed; this is the problem of individual development or ontogeny and is not essentially different from the general problem of growth. But it is clear that the processes of phyletic evolution and of ontogeny must be considered together, since evolutionary history is in reality the history of a succession of individual organisms, each developing from its germ, i.e. of ontogenies; and the ontogenetic process, so faithfully repeated in each individual as it comes into existence, is itself a product of evolution, having originated in the remote past. The succession of individuals has undergone progressive diversification, culminating in the present condition. We may describe our problem, then, as the problem of the factors underlying the synthesis of a highly special process, that by which the diffusely distributed nonliving materials and energies of nature are brought together in a special kind of unification and transformed into a living organism. (shrink)

If we may rely for our evidence on simple observation, it would appear that the tendency of random or unguided activity in external nature is opposed to the development of complex organization and favorable to structural simplicity—in the sense of uniformity in the distribution of elements. This anti-organizing trend of purely physical processes is illustrated in ordinary large-scale mixing and stirring operations, as well as in the automatic increase of entropy with time in systems subject to the laws of thermodynamics. (...) It is common experience that complex systems which are the seat of physical activity tend to become simpler when left to themselves, i.e., they lose organization. Recently Eddington has given the whole matter an admirably clear expression: “Entropy may most conveniently be described as the measure of disorganization of a system.... We can see chance creeping in where formerly it was excluded.” Unless counteracted by directive action the casual or random element in nature tends to increase. If things are left to chance, not only does organization of any high degree of complexity fail to develop, but what organization there is tends to lapse or disappear. Hence in those cases, such as living organisms, where the existence and activity of the system depend on a special and complex organization, it appears necessary to assume the continued operation of a stable directive influence or factor which pervades the whole system and excludes or compensates casual factors as far as possible. The presence of this factor is what makes possible the development and maintenance of the organization required for vital activity. (shrink)