Introduction: Subject and Method of Theoretical Biology

Biology is the science of life, or more correctly, of living beings. It is the science of the laws of motionThe Russian "движение" (dvizhenie) means both "motion" and "movement" in the broadest philosophical sense, encompassing all forms of change and development in matter. (in the broadest sense of the word) of organized living matter. Given the immense diversity of forms and functions of living organized matter that we find in living beings, it becomes understandable that it was necessary, first of all, to describe and bring order to this diversity of forms and functions, as well as to establish certain regularities"Закономерность" (zakonomernost') is a key term in Russian scientific philosophy, meaning law-like regularity or pattern, stronger than mere regularity but not quite a strict law. within it. Initially, attention was directed mainly to those manifestations of life that could be observed and described under natural conditions (such as reproduction, growth, metamorphosis, way of life). Based on similarities in the structure and functions of certain organs, for example the reproductive organs, and in the mode of reproduction, living beings were grouped together, and thus, with further deepening of knowledge about the structure of organisms, the concept arose and species were differentiated. However, this grouping and differentiation of various organisms by their structure and way of life received scientific, theoretical foundation only in the theory of evolution founded and developed by Darwin, according to which all the diverse forms, the various species, arose from one another. Only the recognition that all existing different species possess varying degrees of "blood relationship" to each other made possible the construction of a genealogical tree of species, on the basis of which it became possible both to explain already discovered regularities and to find new ones. The theory of evolution had equally decisive significance for deepening knowledge regarding the regularities of various forms of the aforementioned life phenomena, such as reproduction, metamorphosis, and others, as well as for the doctrine of the emergence and preservation of new forms that developed during this time, i.e., for the doctrine of inheritance of traits closely connected with evolution, which received its scientific foundation in Mendel's laws of heredity. Thus, as the main branches of biology, there developed morphology as the science of forms and structure of living beings, embryology as the science of individual development and formation of forms and organs in individuals, the doctrine of heredity and the origin of species, or the doctrine of the history of origin of living beings. As for such life manifestations and functions as reproduction, fertilization, way of life (mode of nutrition, general conditions of existence, etc.), biology even today is understood as the study of these life functions that can be observed and described under natural conditions. The various, extremely diverse forms of these life manifestations received their theoretical natural-historical explanation on the basis of evolutionary theory in connection with the explanation of the diversity of structure and with the descriptive history of development of various living beings.

Thus, evolutionary theory is that theory to which the material accumulated by descriptive biology led regarding the diversity of forms and life manifestations of organisms observable under natural conditions, and which became the guiding principle of these investigations.

Gradually, however, it became increasingly clear that the description of structure, development, and life manifestations ultimately reveals only the regularities of manifestation of living matter, only the result of its laws of motion, and not these laws themselves; from this it follows that evolutionary theory is a theory of the manifestation of living matter in the course of history, that it takes into account only part of life phenomena and does not represent a theory of the law of motion of living matter that leads to these phenomena. Evolutionary theory is thus the theoretical completion, the greatest scientific achievement of the first descriptive period of biology. When we designate evolutionary theory as the theoretical completion of the first, descriptive period of biology, this is in no way contradicted by the fact that rich experimental material (especially from animal and plant breeders) also served to substantiate this theory. For the content and significance of a theory, what is decisive is not the methods of substantiation, but the phenomena subject to explanation.

Correspondingly, those directions and branches of biology developed more and more that studied the laws of motion of living organized matter, which find their expression in various observable life manifestations and forms. This led to the development of physiology, developmental mechanics"Механика развития" (mekhanika razvitiya) was the Russian term for what is now called developmental biology or experimental embryology, following Wilhelm Roux's "Entwicklungsmechanik"., genetics, i.e., experimental sciences, due to the striving to analyze those individual acting forces or movements and changes within the organism that lead to the given life manifestations. Thus, physiology studies the functions and mechanism of individual organs composing the organism as a whole, their metabolism of substances and energy, the laws according to which they react to external influences, i.e., their irritability; developmental mechanics investigates those factors or conditions that determine the formation of forms and functions during embryonic development, whereby, also using experimental methods, it systematically influences the course of this development and changes or excludes certain conditions. Thus, modern genetics strives, through systematic crossings and simultaneous cytological investigation of chromosomes, to derive the observed laws of heredity from those laws according to which reactions and changes of the hereditary mass located in the germ cells occur. In parallel with the development of these sciences and with deeper penetration into individual processes and their mechanism, i.e., with the clarification of the regularities and forces acting in them, more and more attention was paid to the physical and chemical phenomena participating in these processes, to the study of these phenomena, whereby attempts were even made to reduce individual life processes in the organism exclusively to them.

Here we must point out the following. The essential distinction of sciences like physiology, developmental mechanics, genetics, and in general those we unite under the name of experimental biology, lies not at all in their experimental character (as is often portrayed) in contrast to earlier branches of biology, such as comparative morphology and descriptive biology. The essential distinction of these newly developed divisions of biology lies in the new and deepened formulation of questions and in those new tasks that these sciences set for themselves. In this, the experimental method is a natural, but by no means the only and decisive means for solving these tasks. The essential distinction and novelty of the tasks set by these sciences consisted precisely in the striving to find the laws of motion of living matter and with their help to explain the regularities of various forms of their manifestations under various conditions. These sciences set themselves the task of studying those laws of motion of living matter that are inherent to it and necessarily manifest themselves in all life phenomena. Just as the resolution of the first task—finding regularities in the forms of manifestation of living matter—inevitably had to begin with the description of individual forms and life phenomena, their classification and systematization, so naturally the resolution of the second task had to begin with the description and finding of individual laws of motion of living matter underlying various individual manifestations of life and processes of form formation.

Thus developed various special divisions of physiology as the doctrine of metabolism of substances and energy, which split into individual branches corresponding to various energy-supplying processes, such as the doctrine of respiration, of fermentation, of nitrogen, fat, intermediate metabolism, of syntheses in the organism; further, the doctrine of reactions of the organism and its irritability, which split into doctrines of muscle contraction, of conduction of stimulation together with chemical and physical phenomena accompanying these processes; the doctrine of reflexes, etc. We observe similar things in embryology, where developmental mechanics (or, as it is now often called, developmental physiology) founded by W. Roux subjected to analysis individual, especially the earliest stages of development, investigating the different fate of individual cells and the factors determining this fate, including chemical and physical phenomena. We see the same thing in genetics, which in its modern form has transformed mainly into experimental investigation of chromosome structure, its changes, etc., in order to thus derive the external manifestation of traits and the regularities of their inheritance from the laws of motion and acting forces inherent in the carriers of these hereditary traits.

Thus, Darwin's theory gave a general principle for explaining the diversity of forms and functions of organisms as they appeared on the earth's crust, a theory encompassing the regularities of forms of living beings, their origin and their law of motion for all living organisms; now the question arises whether such a theory is possible for all living organized matter regardless of the historical conditions of its development. In other words, is it possible to find such general laws of motion of living matter that are valid in all its forms of manifestation, however diverse these forms may be, i.e., do there underlie all the various laws of motion that have already been found or will still be discovered by individual biological disciplines in the field of genetics, physiology, developmental mechanics, etc.—do there underlie them such general laws of motion of living matter, of which these individual laws of the named special divisions of biology represent various manifestations, just as the special, individual laws of descriptive sciences—morphology and descriptive biology—represent various manifestations of the general regularities of evolution? But this question is equivalent to the question of whether living matter has its own special laws of motion. And since we have defined biology as the science of the laws of motion of organized living matter, this question is analogous to the question of whether there exists a science of life, biology, or whether it is merely a division of applied physics and chemistry. For if we attribute to living, organized matter its own laws of motion, inherent precisely to living matter and only to it, being its attribute, the form of its existence, then these laws must manifest themselves in every form of manifestation of living matter. Then all special laws of motion that have been and will be discovered by individual branches of biology, such as the regularities of physiology, developmental mechanics, genetics, etc., must prove to be special cases, special manifestations of general laws of motion inherent in living matter, even if these manifestations occur under historically conditioned and substantially altered conditions, and therefore in a substantially altered form. There are only two possibilities to avoid the inevitability of this conclusion.

1. We can assert that living matter has no laws of motion of its own, that the laws of motion of living matter are essentially the same as those of non-living matter. Then, being consistent, we have no right to speak of living matter at all. But then biology is nothing other than applied physics and chemistry, i.e., the application of the laws of physics and chemistry to those complex systems that living beings represent.

2. Or we assert that living beings have their own regularities, their own laws of motion, but that these laws are conditioned not by the state, organization, structure of the matter of living beings, i.e., are not a form of manifestation and existence, an attribute of living matter, but are the result (and this conclusion is then inevitable) of supramaterial, divine forces that do not change the laws of physics and chemistry but constantly direct them.

The first of these viewpoints is defended by the direction known in biology as mechanismBauer uses "механицизм" (mekhanitsizm) for mechanism and "витализм" (vitalizm) for vitalism, representing the two major opposing philosophical approaches in early 20th century biology., the second by vitalism. Both directions stop before reaching the decisive point and try to cover this stop with false philosophy. But scientific research does not stand still and, despite the restraining influence of these two directions, penetrates ever deeper into the special and general regularities of motion of living matter. There exists, of course, only one correct way to prove the inadmissibility of both indicated viewpoints that deny the existence of general laws of motion inherent in all living matter and only in it, as forms of existence of this organized, living matter: this way consists in finding and investigating the general laws of living matter, in revealing how they manifest themselves in various forms in different forms of living beings, and on the other hand—in showing that in all various particular regularities the same general regularities of living matter manifest themselves, that in the diverse regularities of life phenomena changing in the course of development of living beings on earth, the same laws of motion inherent in living matter and only in it find their expression.

Thus, we come to the conclusion that if we attribute to living organized matter special laws of motion inherent only to it, i.e., if we speak of a special science—biology—and at the same time want to remain on the ground of materialism, then we must not only give an affirmative answer to our question of whether it is possible to find such general laws that underlie all laws of motion in individual, special areas of biology, or whose particular concrete manifestation these special regularities of physiology, developmental mechanics, genetics, etc. serve, but we must also say that finding these laws, making these generalizations and applying their results as a guiding theory in research is the urgent immediate task of theoretical biology.

Based on all the above, we can form the following schematic representation of the development of biology, its special, experimental-descriptive, and general-theoretical parts:

Of course, each point of this scheme needs clarification.

First, we equate the special with the descriptive-experimental, on the one hand, and the theoretical with the general, on the other. It seems to us that this equation is justified and basically correct. For the theoretical treatment of any phenomenon consists precisely in abstracting the general, the regular from the great diversity of special, concrete phenomena and investigating this particular abstract regularity, analyzing and revealing its various possible forms. We assume certain conditions and determine how the process must proceed under given conditions, in what form the regularity will manifest itself under given concrete conditions. Then we compare the result obtained in this way with the data of experience, investigating how these phenomena proceed in nature where the conditions we have assumed are realized, or we ourselves create these conditions in an experiment and investigate whether the process really proceeds as we have derived it from the general law we have abstracted under the conditions we have assumed. If the general law thus abstracted is really justified, i.e., if the conclusions drawn from it under the assumption of various conditions are confirmed in experience or experiment, if our law really is a general regularity, then with its help and on the basis of analysis of the concrete conditions given in experience, we can predict the course of processes or, by means of corresponding changes in conditions, direct them in the desired direction, i.e., then this abstract general law will become the property of theoretical science. In this sense we speak of theoretical science as opposed to experimental or descriptive science. We speak of theoretical science when we proceed from the totality of purely abstract, general laws of a given field of phenomena obtained on the basis of all the experience of a given science and represent the phenomena observed in experience as special cases of these laws under certain conditions. We speak of descriptive or experimental science, on the contrary, when, proceeding from observations and individual experimental results, we collect factual material for theoretical science, or, generalizing it, arrive at general regularities.

The great merit of Galileo consists in the fact that he introduced systematic experiment and thereby discovered a new kind of induction, which, leading with the inevitability of logical necessity to causal knowledge, at the same time proved to be creatively fruitful in the highest degree for the advancement of science.

At first glance it may seem that the difference here reduces only to the method of presentation. But this notion is completely wrong, since, first, experimental, descriptive science differs from theoretical not only in how it presents facts and general regularities: besides, the laws of experimental, descriptive science are derived in theoretical science in a completely different way, so that the difference between both sciences lies not only in the method of presentation, but also in the method of investigation, and second, the laws obtained by theoretical science are not equivalent in their content to the laws obtained by experimental-descriptive science through generalizations.

Regarding the first difference, descriptive-experimental science obtains laws through generalization of observations and experimental data, but a law derived in this way is by no means yet a theory of a given group of phenomena and therefore by no means constitutes the content of theoretical science. This law only then becomes the content of theoretical science when it can be derived from certain general laws and theoretical representations as a special case for those conditions under which the law was found. Then and only then do we speak of a theory of given phenomena. Thus, experimental science obtains its laws from experience through generalization, while theoretical science obtains the same laws on the basis of general abstract propositions and assumptions, whereby certain concretizing conditions are accepted. Of course, these abstract laws and assumptions are also abstracted from experience and assumed on its basis, but they go beyond the boundaries of immediate experience.

Let us clarify this difference with several examples.

As the first, let us take the law of falling bodies from mechanics. In textbooks of experimental physics, this law is presented as the result of generalization of systematically conducted observations and experiments and measurements of the path traveled by falling bodies in various time intervals. Indeed, Galileo obtained this law precisely in this way, and since Galileo's time the path of systematic causal-analytical experiment has been considered the model of experimental research in biology as well. W. Roux thought of this model when founding developmental mechanics. Hartmann also points to it in his "General Biology" as the path that will lead biology forward:

The law obtained by this path states, as is well known, that every freely falling body (if air resistance can be neglected) falls with constant acceleration and that the distance traveled equals half the product of this acceleration and the square of time, i.e.,

s = ½gt²

where s is the distance traveled, g is the acceleration, and t is the time.

But this same law in theoretical mechanics is obtained by a different path: not on the basis of generalization of observations, but as a special case of much more general propositions. These general propositions are Newton's laws of motion and his law of gravitational attraction of masses. As is known, the latter states that the force with which two masses attract each other is proportional to these masses and inversely proportional to the square of the distance, i.e.,

K = f · (m₁ · m₂)/r²

where K is the force of attraction, m₁ and m₂ are both masses, r is their distance from each other, f is the proportionality factor or the force itself in the case of unit masses at unit distance.

Newton's second law of motion states that force equals the product of mass and acceleration of a moving body, i.e.,

K = m · d²s/dt²

From these general laws in theoretical mechanics, Galileo's law of falling is derived as a special case. Namely, if we denote the mass of the falling body by m, the mass of the earth by M, then we obtain

f · (M · m)/r² = m · d²s/dt²

or

f · M/r² = d²s/dt²

and since compared to the radius of the earth we can neglect the change in distance, i.e., r can be considered constant, we have:

d²s/dt² = Const. = g

i.e., during falling the acceleration is constant, and the path traveled in time t we obtain from this formula by double integration with respect to dt, which directly leads us to the law of falling

s = ½gt²

To what extent we can already speak here of a theory of the law of falling and from where, by what path these general laws of motion were obtained, we will discuss later when we examine several examples from various fields. In any case, we see that the law obtained by the second path gives more in its content than the law obtained through generalization of analytical experiments and observations. Thus, for example, it shows that this is an approximate law, that it is valid only insofar as the length of the path traveled during falling can be neglected compared to the radius of the earth. None of this can be derived from the law obtained through generalization of experimental data.

Let us take as a second example the well-known Boyle-Mariotte law. It states that at constant temperature the pressure of a gas is proportional to its density or inversely proportional to the volume of a unit mass, i.e.:

pV = Const.

if p is the pressure and V is the volume of a unit mass. This law is also presented in experimental physics as a generalization of systematically conducted analytical experiments and observations on various gases at various pressures, etc., and indeed it was obtained in this way.

In theoretical physics, however, this law is derived as a special case from certain general representations and laws of motion of gas molecules. It is assumed that gas consists of individual molecules moving with different velocities, whereby it is assumed that the velocities are distributed along three coordinates according to Gauss's error curve, and that the mean square of velocities is proportional to temperature and, consequently, constant at constant temperature. In addition, it is assumed that the general laws of motion are valid for molecules as well. Given the assumption of these general representations and laws, the Boyle-Mariotte law can be derived as a special case.

Indeed, let us denote the weight of individual molecules of a given gas as m, the number of molecules moving with velocity between v and v + dv in a unit mass as N, then the number of molecules passing through a unit surface in unit time with this velocity will be equal to Nv, and the quantity of their motion—mNv²; if we take the mean square of the velocity of the corresponding normal component, then the pressure on the wall will equal one third of this quantity, i.e.,

p = ⅓mNv̄²

if p is the pressure and v̄² is the mean square of velocity. But since mN is nothing other than the weight of a unit mass, i.e., density ρ, we have

p = ⅓ρv̄²

or

pV = ⅓v̄²

and this is the Boyle-Mariotte law

pV = Const.

if we recall the general assumption that the mean square of molecular velocities depends on temperature and consequently is constant at constant temperature.

In this case we have again derived a law generalized from experimental data as a special case of more general laws and propositions. Again we see that in the second case the same law states more in its content: it contains statements also about molecules and their motion, about which the law obtained by the causal-analytical path through generalization says nothing, and which are not given directly in experience. Again the question arises, from where do we take these general representations and propositions, which, on the one hand, are abstract and general, and on the other—have richer content. From these general, abstract representations and propositions one can, as is known, derive not only the Boyle-Mariotte law, but, by accepting corresponding conditions, also the remaining gas laws obtained through generalization from experience. Therefore we speak of the kinetic theory of gases as part of theoretical physics. These general representations and laws of the kinetic theory of gases contain the particular laws of motion of all gaseous matter, under whatever conditions they may manifest themselves, as long as the parts composing this matter, i.e., the molecules themselves, do not undergo changes—in other words, as long as chemical changes do not arise in it. This also leads us to the answer to the question of where and how these general abstract propositions and representations are obtained, such as Newton's laws of motion in mechanics, Newton's general law of gravitational attraction of masses, the propositions and representations of the kinetic theory of gases. They are not the result of further generalization of any empirical law, for example the law of falling, or the Boyle-Mariotte law, but the result of bringing together various empirical laws and individual experimental data, the condensation of all these experimental data and empirical laws into certain general propositions and representations, which themselves already go beyond the limits of direct experience and are necessarily abstract, since they abstract the general, essential, namely the general laws of motion inherent in a given material state. Only on the condition that we can abstract these general laws of motion inherent in a given material state and represent various individual empirical laws as manifestations of these general laws of motion under certain conditions—only then do we speak of a theoretical or general science of a given field. The collection and presentation of individual laws of a given field obtained through generalization is the task of descriptive and experimental science.

What has been said is correct not only for mechanics and other fields of physics. We find the same thing in chemistry, where on the basis of the same criterion we distinguish general or theoretical and special, organic and inorganic chemistry. General or theoretical chemistry deals only with those processes and laws that are common to all chemical processes and valid for all of them, under whatever special conditions these processes may proceed. It presents those laws of motion that are accompanied by changes in the structure of molecules, whatever special structure these molecules may possess. It formulates these laws as special cases under given conditions of some more general representations and propositions about the structure of molecules and their motion, it derives them from these propositions. Thus, Faraday's laws of electrolysis, found through generalization of the results of causal-analytical experiments, are derived in theoretical chemistry from general representations and propositions about the structure of molecules and their electrolytic dissociation. Thus, in theoretical chemistry, those regularities according to which various reactions occur with respect to establishing equilibrium, speed, and progression over time are derived from general representations about motion and structure, and the laws of chemical dynamics obtained in this way constitute the subject of theoretical chemistry. The presentation of various laws of electrolysis, chemical statics and dynamics on the basis of generalization of corresponding observations and experiments would not yet be theoretical chemistry. Only when we can present these laws on the basis of representations and general propositions obtained through abstraction, i.e., condensation of various empirical propositions about the motion of chemical compounds, when we can derive them as special cases, only then and only to that extent do we speak of theoretical or general chemistry. The examples given above sufficiently clarify this.

Here, consequently, our equation of the general with the theoretical, on the one hand, the particular with the descriptive-experimental, on the other, is correct.

How do things stand with biology? At first glance it seems that between physics and chemistry, on the one hand, and biology, on the other, there exists an essential difference. Physics deals with the laws of motion of non-living matter, insofar as changes in chemical structure do not occur in it and regardless of what form these bodies exist in, whether the given movements actually occur in nature and what regularities regarding existence, distribution and changes over time the diverse concrete physical forms of motion are subject to. Chemistry also deals with the laws of chemical structure and its changes regardless of where and in what quantity these various chemical bodies occur in nature and what regularities regarding existence, distribution and change over time the diverse concrete chemical bodies in nature are subject to. Thus, for example, the physics of gases does not deal with the regularities of pressure changes, formation, etc., of gas accumulations existing in nature and their changes over time. Applied physics of gases partially deals with this for practical reasons: meteorology, studying the regularities of winds, etc. Hydrodynamics does not deal with the regularities to which liquids occurring in nature with their movements, emergence and changes over time are subject; for example, it does not deal with the regularities of movement of rivers found on earth and their changes over time. The same applies to electrodynamics, etc. Chemistry also does not deal with the regularities to which the existence, quantity, formation, distribution and changes over time of various chemical compounds in nature are subject. A division of applied chemistry in geology partially deals with this.

Biology, on the contrary, deals with living beings existing in nature, with natural bodies as they are given in nature, and its first task was, as we see, to investigate precisely the existence of the form of these living beings, as well as the regularities of their formation, distribution on earth and their changes over time.

However, this difference is only a difference in the historical development of the direction of research in these sciences and is not conditioned by the very essence of the subject.

We think that the difference in the development of the direction of research was conditioned by the different significance that inorganic and organic, living nature and their laws of motion have for humanity, for satisfying its practical needs.

Inorganic nature and its laws of motion have always had the significance for humans that under given conditions of existence they could use and direct them, could with their help make their first working tools, and later build their machines. The first, primitive working tools were simple machines, like the lever, etc. Mechanics developed from the practical need to improve these machines: dynamics developed from the same needs, to build better tools or to better use them with the help of the laws of ballistics. Hydrodynamics arose from the practical need to build hydraulic pumps and machines based on the laws of liquids, but not from the need to use natural water forces as such, since for better use of the latter, corresponding machines with corresponding knowledge of the laws of hydrodynamics and mechanics are necessary. Aerodynamics developed especially in connection with aeronautics. Thermodynamics also developed in connection with the development of the steam engine, and not in connection with the question of where and in what form useful energy transformations occur in nature for us, etc. The same applies to a large extent to chemistry, which arose from the practical need to create compounds and substances useful to humans from natural products, so as not to depend on products existing in nature, occurring only in limited quantities. The predecessor of modern scientific chemistry was alchemy, which gathered many valuable chemical observations and knowledge in the striving to create precious gold from worthless substances.

But organized living matter, living beings have always played a different role for humanity. Plants and animals have always been conditions of existence of paramount importance for humans; they were their food, and moreover in the form in which they occur in nature; humans could use them only insofar as they knew their distribution, conditions of existence in nature, reproduction and way of life. The first methods by which humans obtained food were fishing, hunting and gathering certain fruits found in nature. Even today there can be no talk of manufacturing food products independently of living beings, plants and animals found in nature. This conditioned the fact that humans were primarily interested in knowing the various living beings found in nature, their distribution and reproduction, their way of life and those regularities to which the conditions of their appearance in nature are subject. Because of this, the natural-historical moment first and most strongly developed in biology, while the experimental direction, investigating the general laws of motion of living matter regardless of the accidental conditions of its appearance, arose only later. In inorganic sciences we observe the opposite picture. It would be wrong, however, to think that this difference is conditioned by the object itself subject to investigation, by the difference in state and laws of motion between living and non-living matter. Non-living nature has its history just as living nature doesHere Bauer makes an important philosophical point about the historicity of both living and non-living nature, anticipating later developments in evolutionary cosmology and geology., and the ultimate goal of all science consists in investigating the regularities of this history of nature and on their basis predicting phenomena and controlling them.

But in order to find the regularities of the history of living or non-living nature, it is by no means sufficient to know the conditions of existence, distribution and change over time of the given diverse forms of phenomena and motion. Only in that case can we speak of historical regularity, if from the laws of motion inherent in given matter we can derive the necessity, the regularity of these changes over time, the emergence and disappearance of some forms of motion and the appearance of others—if on the basis of these general internal laws of motion characteristic of given matter and inherent only to it, we can show that these regularities and their changes over time are realized with internal necessity through the particular and accidental. There exists only one field of knowledge, one science, where this task is solved, where on the basis of general internal laws of motion obtained through far-reaching abstraction, i.e., condensation of the most diverse empirical propositions, the necessity of historical regularity in the above-indicated sense is shown. This is the Marxist doctrine of society. The general laws of motion of human society found by Marx gave a method for investigating any form of society, and precisely therefore on their basis, through analysis of any social structure, one can predict with the inevitability of a law of nature the changes (and their direction) of this structure, as well as systematically influence the course of these changes.

Comparing everything said, we see that the difference between inorganic sciences and biology is conditioned only by the historical development of these sciences, and not by fundamental differences in the goal they set for themselves, or differences in the method by which this goal is achieved or can be achieved.

Thus, our conclusions regarding theoretical sciences are fully applicable to biology as well. Moreover, we see in inorganic sciences too that the historical regularities of non-living matter, the inevitability of emergence, aging, death and changes of celestial bodies, as well as the direction of these changes, insofar as they have been successfully investigated so far, could be investigated precisely only on the basis and with the help of general representations and laws of motion obtained by theoretical physics and chemistry. Without the general laws of motion of mechanics, gravitational force, gas laws, thermodynamics, laws of radioactivity, etc., natural sciences would not have arrived at modern representations about the origin and history of celestial bodies. The same applies to the history of our earth, its layers, etc.

We now come to the second point of our scheme that needs explanation—this is the question of the content and significance of evolutionary theory and its relation to the general theory of living matter within the framework of theoretical or general biology. As for the content of evolutionary theory, it is undoubtedly correct to present it as an achievement of theoretical biology in the sense indicated above. Evolutionary theory is not merely a generalization of direct empirical data or an empirical law. It is a condensation of a large number of various empirical data and regularities of comparative morphology, descriptive biology, etc., and goes beyond the limits of direct experience; it states a general regularity obtained through abstraction and on the basis of certain general representations about living beings—a regularity stating that living beings on earth, animals and plants, arose from one another during the history of the earth, that they possess a common genealogical tree, i.e., are in more or less close "blood" relationship to each other. All individual empirical data obtained by comparative morphology, zoogeography, paleontology, etc., can be presented as certain special cases of this general principle, or this general regularity. Even more: evolutionary theory also possesses a historical-temporal moment, insofar as it contains within itself the necessity of the appearance of new forms and the death of others. But it does not state any historical regularity. From evolutionary theory in its modern form and with its modern substantiation, nothing can be derived regarding which forms of living beings could or should have appeared under certain conditions and in a certain historical period, what regularities are necessarily realized in the course of the history of living beings through the particular and accidental. Nothing can be said about in what and in what direction later forms of life should have differed from earlier ones. The principles of evolution and evolutionary theory in their modern form contain the proposition that various forms of living beings, that living matter has its history, but about the laws of this history they say nothing and allow no statements. That evolutionary theory, as Darwin substantiated and developed it, did not go beyond these limits is, of course, not accidental. This is connected with the fact that it is the theoretical achievement precisely of the first, descriptive phase of biology. According to the then degree of development of science, it could not go further. It reflected the shortcomings of its epoch. True historical regularities in the sense set forth above can be recognized only on the basis of general laws of motion inherent in living matter. Only knowing these general laws of motion can we show how they change their form when conditions change and in what direction such a change is possible and must occur. But on what general laws characteristic of living beings could Darwin rely? On those that could be obtained through generalization from the empirical data of the first, descriptive phase of biology, i.e., on the laws of reproduction, variability and heredity. In substantiating his doctrine, Darwin fully used them. But he could rely only on these general laws of manifestations of living matter, and not on the internal laws of motion of this matter itself. A general theory of living matter did not yet exist then. There were also no special laws of motion of individual phenomena. There was no theory of heredity in the sense of modern genetics, attempting to derive the phenomena of heredity from the laws of motion inherent in hereditary substance. A similar theory of variability, reproduction, etc. is absent to this day. Therefore it is understandable that in modern biology there are attempts on the part of genetics to deepen evolutionary theory, to reduce it to the theory of heredity. That these attempts remain unsatisfactory is explained precisely by the fact that genetics itself can operate only with those special laws of motion of living matter on which the laws of heredity are based, and not with those general laws of living matter that are obtained through condensation, i.e., abstraction, not only from the phenomena of heredity, but also from the phenomena of growth, reproduction, adaptation, development, etc., i.e., from the empirical data of physiology, developmental mechanics, etc. as well. Only on the basis and with the help of such general laws of living matter can successful further deepening of evolutionary theory be achieved, only on the basis and with the help of such laws, i.e., a general theory of living matter, can evolutionary theory be developed and deepened into a true historical theory that encompasses historical regularities and their necessity and allows statements regarding them.

In its modern form, evolutionary theory not only allows no statements regarding historical regularities, i.e., regularities concerning different species of animals and plants compared to their past; it even principally denies any regularity in the sense of a regularity realized over time with necessity through the particular and accidental, i.e., in the sense of directionality over time. Thus, we have in modern evolutionary theory a somewhat paradoxical position, namely a theory that postulates and substantiates the history of living beings, but principally denies the existence of regularities of this history. In it the moment of the accidental dominates, covering the moment of the historically necessary, regular.

This paradoxical phenomenon has two causes: first, any science must categorically reject any theory that assumes that historical regularities, in the sense of directionality, orthogenesis"Ортогенез" (ortogenez) refers to the theory that evolution proceeds in a predetermined direction, which Bauer rejects as vitalistic., are caused by immanent, non-material, directing forces, or attempts to explain these regularities in this way, i.e., in a vitalistic direction. Therefore, all explanations and theories proceeding from such assumptions and leading or even only capable of leading to them should be rejected in principle as unscientific. In the struggle against these tendencies, scientific biology developed, which, adhering to the postulate of the history of living beings, increasingly proved the presence of the element of the accidental in this history.

Second, the moment of the historically necessary, regular, realized through the particular and accidental, could not and cannot be recognized, grasped and materialistically explained if it does not rely on the general laws of motion inherent in living matter. These two causes combine in modern biology in such a way that due to the absence of a materialistic explanation for historical regularities, i.e., for those that are necessarily realized over time in a certain direction, biologists principally deny these regularities and their existence, presenting them as contradicting the materialistic-dialectical, scientific way of thinking and worldview.

But that such a viewpoint is incorrect is shown to us by the fact that at a certain degree of development of productive forces, the direction of development of the social structure is necessarily predetermined and "the wheel of history cannot be turned back." It is sufficient, for example, to know Lenin's argumentation against the NarodniksThe Narodniks were Russian populists who believed Russia could bypass capitalism. Bauer uses Lenin's critique of them as an example of proper dialectical-materialist understanding of historical necessity. based on the general laws of motion of society to see that the assumption of historical regularity in the sense of one that is necessarily realized in a certain direction in no way contradicts dialectical materialism, but, on the contrary, represents an essential element of the latter. On the other hand, on the example of both Marxism and some of the above-mentioned areas of inorganic natural sciences, we see that materialistically, i.e., scientifically, to comprehend and explain these historical regularities is possible only on the basis and with the help of the general laws of motion of given matter.

With this we have answered the question about the relationships between the theory of evolution and the general theory of living matter within the framework of theoretical biology according to our scheme given above. The theory of evolution needs deepening in order to become a true historical theory of living matter. This further development can be achieved only on the basis of the general laws of motion of living matter. Therefore, the immediate task of theoretical biology is the development of the general laws of motion of living matter, i.e., the theory of the latter. The task facing theoretical biology, which it is approaching to solve, consists, therefore, in presenting and deriving the empirical laws and data of descriptive and experimental biology with its divisions as particular moments of development of more general laws and representations about living matter that go beyond the limits of direct experience. These general laws must be laws of motion inherent in living matter, i.e., characteristic only of it. But they must represent the laws of motion inherent in it everywhere and always, the form of its existence, in whatever special forms they may manifest themselves. Therefore they must be valid for all living matter and only for it. They must allow us to derive from the analysis of concrete conditions the appearance of special forms of motion and the direction of their change. This is a long path. The first and greatest step in this direction was taken by the evolutionary theory founded by Darwin. Further significant preliminary work was accomplished by the developing special, experimental sciences that approached the investigation of those laws of motion of living matter from which individual regularities of manifestations of this matter can be derived, primarily the doctrine of heredity, or genetics, which strives to present its regularities as special cases of more general representations. The next step must be taken in the direction of a general theory of living matter, in order to approach with its help the solution of the tasks indicated above. To clarify how far this is already possible now, to show that this path is open to us, and to take a further step in this direction—this is the goal of the present book.