Biology, Physico-chemistry and History
Abstract
By abstaining from seeking to define the concept of life, modern biology, as a science autonomous (but not separate) from physico-chemical sciences, is ruining itself, by rendering impossible the construction of a specific objet. This article restates this question, by studying how neo-darwinism palliates the deficiency of the physico-chemical explanation of the living being with an historical explanation, under cover of the theory of information; and how it fails to articulate these two explanations, owing to a misappreciation of the concept of time.
The biochemistry and the notion of life [1]
In his first Leçons sur les phénomènes de la vie communs aux animaux et aux végétaux, Claude Bernard explicitely writes that there is no necessity for us to pay attention to the notion of life, because biology has to be an experimental science and, therefore, there is no reason for it to give any definition of life; that would be an a priori definition and “the method of defining and inferring everything from a definition may be suitable for the spiritual sciences, but it is contrary to the spirit of the experimental sciences”. Accordingly, “it’s easy enough to agree on the word life to use it” and “it is illusory and chimerical, contrary to the very spirit of science, to seek an absolute definition of it” [2].
Apparently, biology has held fast to that opinion, since it persists in being ignorant of the notion of life and in being satisfied with the analysis of the objects which common sense qualifies as living; analysis which enables one to show some physico-chemical characters common to these objects. This exclusively analytical and experimental method has greatly strengthened the efficiency and the scientificity of the biologist’s work. Nevertheless, it brings a “physicalisation” to such an extent that it seems sometimes that, in order to make biology scientific, it is necessary to deny any specificity to its objects.
Nowadays, biochemistry (particularly in the form of molecular biology) is doubtlessly the ultimate stage of this analytical and experimental method; all the other biological sciences are more and more reduced to it. It shows the perfect identity of the nature of the matter, and of the laws which govern it, in living beings and in lifeless objects. Merely, in the living being, this matter has some molecules (and some inherent reactions) that, though following the same physico-chemical laws as the other molecules, are not usually to be found in lifeless objects nowadays (it is especially the case of the macromolecules, like nucleic acids and proteins).
Hence, biochemistry is only to be distinguished from chemistry which studies the matter of lifeless objects because a quite appreciable number of such signal chemical differences between the compositions of living being and lifeless objects are to be found, within the same physico-chemical framework. It follows that we may consider biochemistry to be epistemologically chemistry because it does not differ fundamentally from the sciences which are regrouped under this name, but only by the chemical characters of its objects (as organic chemistry differs from inorganic chemistry).
The unity of the material composition of living beings is such that we can admit that the small biochemical variations between species, between the individuals of a same species, or in the same individual at different moments of its life, are not sufficient to corrupt the unity of the living phenomenon. That explains some confusion between the study of the life and the study of the matter of living beings; from which a temptation to reduce biology (etymology: the science of life) to biochemistry (etymology: the science of the matter of the living beings) by denying any specificity to the living. In other words, it is tempting to differenciate living beings from lifeless objects by using the same criterion as that which distinguishes biochemistry from the rest of chemistry.
These chemical characters, which are peculiar to living beings, are bound tightly enough one to another; they form a quite credible picture of a “living-being-in-general”, that would be compounded with all the chemical characters peculiar to living beings (nucleic acids and proteins, associated enzymatic processes,…) Nevertheless, restricting the specificity of living beings to such chemical characters would be denying it, because it is reducing it to a difference that is qualitatively analogical to that which distinguishes two lifeless objects one from the other. There would be only a gathering of objects which would differ one from another in physico-chemical characters. There would be no reason to divide this gathering in two classes, living and lifeless – all the more as the chemical criteria, according to which this division would be made, are not entirely defined, and the reason of their choice remains unknown, since it is only founded on the common sense that indicates as living some objects which, by the analysis, show some common chemical characters. The notions of living and lifeless would not be grounded; they would be words to remove from our vocabulary.
These chemical characters peculiar to living beings, however right they may be, are only useful indications, but they are not sufficient to define the living in relation to the lifeless. By themselves, they do not enable us to encompass the specificity of living being (if it exists); they are not the origin of the choice of the object of biology, they are only attempts to justify by chemistry the choice made by common sense.
Biochemistry shows that is no ghost ordering the machine, and that the specificity of the living being cannot consist in such a ghost. It shows the universality of the laws which rule matter, and that the specificity of the living being does not consist in peculiar chemical laws. But by speaking so, one cannot, as a result of this single remark, talk of the specificity of living being, Therefore, biochemistry cannot present this specificity as a gathering of chemical characters (because such characters differenciate a living being from a lifeless object in a way qualitatively similar to the differenciation of two lifeless objects); but it can deny it only under the form of a ghost or of peculiar chemical laws; otherwise it leaves its field of competence.
That is not fussy epistemology, but a problem which stays in the heart of biology, even though it is not often explicitly stated. A symptom of this is to be seen in the recourse to emergence which is often called to reconcile the evident originality of the living being and its strict observance of the laws which govern the lifeless. Thus, life is presented as a new quality which appears when the physico-chemical organization reaches a certain degree of complexity, without any precision on the way by which this emergence is made, without telling why this emergence is necessary (were not the difficulty to deny the specificity of the living being), without telling how this undefined emerging life is new, being compared with only physico-chemical notions. In these conditions, we have to ask whether this emergence is not only a means of getting rid of the notion of life, with which we do not know how to make a scientific concept: since the articulation of the chemical and the biological levels is supposed to have been made by a qualitative jump (that belongs to magic rather than to a dialectic of nature), it is naturally placed outside of science. After showing that there is no ghost in the machine, biologists suppose one to emerge; as if the ghosts which emerge from a chemical organisation, were more consistent with epistemological materialism than the ones which are supposed to order matter. The question is rarely posed of knowing whether there is still a machine, when the ghost is driven away, and whether the supposed emergence of one does not aim only to keep the machine; so strong is the mechanistic opinion in biology.
Another attitude, quite as symptomatic of the difficulty of conciliating the originality of the living being and its respect for physico-chemical laws, consists in distinguishing diverse levels of pertinence. Nevertheless, the fact that biochemistry has not to consider the notion of life in its work (molecular level), but that this notion of life can display meaning at another level (the cellular level, for example), only displaces the question; how can we articulate biochemistry to this other level, so that from insignificant the notion of life becomes significant? As a matter of fact, this distinction of several levels of pertinence is more diplomatic than scientific or epistemological, since it gives no answer to the question of the specificity of the living being.
Consequently, the problem of this specificity is not yet settled. It is only hidden; either this specificity is illicitly denied (or, what would be the same, is assimilated to chemical characters), or several levels of pertinence are admitted. The question remains opened: is there a specificity of the living being, that is neither a chemical character, nor a supernatural force? The solution would probably consist in a peculiar organization: but which organization would be sufficiently defined to differ from that of the lifeless objects, and sufficiently general to suit all living beings?
[It would be possible here to take up Lamarck’s first materialist definition of a living being: “a body that forms its own substance from that which it draws from the external environment” (see Philosophie zoologique, 1809, vol. I, p. 92-93 ; Hydrogéologie, 1802, p. 112 ; Mémoires de Physique et d’Histoire naturelle, 1797, p. 248) ; Editor’s comment.]
If we exclude the case in which an emergence is admitted, biochemistry seems to answer this question by denying any specificity to the living being (or by reducing it to chemical characters), when it does not simply neglect it. Such a denial belongs to a view in which no distinction is admitted between living and lifeless to preserve an united and coherent universe. Then, a progressive graduation is admitted between lifeless and living, as well for the present forms (the virus, supposed at the limit between lifeless and living) as for the appearance of life on the earth (this appearance is understood as a prebiotic phase without marked discontinuity). This negation of the specificity of the living being, which declares itself materialist, simply confounds epistemological materialism and the sciences of matter. The natural sciences, including biology, have to be materialist; everybody (or almost everybody) will agree with this; but have they to be only sciences of matter?
Nowadays, it seems that biology does not aim to study life (or to study the peculiar qualities of living beings compared to lifeless objects) as much as its pure and simple negation, the levelling and unification of the universe by means of physics and chemistry. As if, in a unifying purpose, denying the discontinuities is better than understanding them. Don’t misunderstand; we do not fail to recognize the interest of biochemistry; what we criticize is this peculiar perversion of biology which consists of giving it as an aim, the negation of its object, and, consequently of itself as an autonomous science. This is a suicidal reductionism, which the results of biochemistry does not impose as much the “spontaneous philosophy” of numerous biologists. It is not here a question of contesting the principles of biochemistry, whose successes are undeniable, but of knowing where to place its limits.
The biochemical explanation
Biochemistry explains the living being by the chemical reactions and interactions of its constituents one with another, and with some elements of its environment; this is its principle. Its ideal would be to give by this means a complete description of the living being (at least, of the cell) in chemical terms. As a matter of fact, such descriptions are only given for some structures and some metabolic processes, which are isolated one from another for the ease of analysis. Therefore, biochemistry has a correct epistemological position in so far as it is an experimental science. Its descriptions of the vital structures and processes are beyond all question at the chemical level.
To step from its current reality to its ideal, biochemistry would have to integrate its local descriptions one with another in a coherent whole. Since the described structures and processes are in close reciprocal relation, the complete description of the living being requires the integration of those, and not only their side-by-side position. The epistemological difficulties begin here; difficulties which are badly reported by the sempiternal formula: “the whole is more than the sum of the parts”.
Two obstacles are met when we attempt to integrate local biochemical descriptions in a whole, which would be a description of the total living being (structure and behaviour). The first one is methodological, the second is ontological (for want of a more accurate term).
The first obstacle proceeds simply from the lack of adequate methods. Integration of the local structures and processes into a whole is understood, in biochemistry, as the result of the interactions of numerous regulations; but, the complexity of these interactions prevents the structure and the behaviour of the total being from being calculated (perhaps that must be understood by the notion of emergence from complexity: the structure and the behaviour of the whole appear as new properties, because they cannot be predicted from the structures and behaviours of the constituents, for lack of an adequate method — in this case, this emergence would be only the mask of our ignorance). Confidence in the progress of mathematical or informatical methodology still remains; but, then, the ontological obstacle arises, which shows that the impossibility of the integration does not proceed only of the failing of current theory (to think that, and to expect future methods is tempting, because, thus, the current principles are not contested), but takes root in the being itself, that is to be explained.
This ontological obstacle is the following. Biochemistry explains the living being by chemical reactions and interactions of its constituents one with another, and with some elements of its environment; but it is well known that, if the dispersed elements of a living being (even though it is as simple as a bacterium) are blended in its natural environment (a culture medium, for a bacterium), we do not obtain an organized and functional living being by reactions and interactions of these elements. Such a self-assemblage would be equivalent to a spontaneous generation, known to be impossible for the present being in the present circumstances. Only viruses and some organelles (such as ribosomes) can be produced by means of a special method, from their constituents in an adequate medium comparable to their natural sphere, the intracellular medium, where they keep their structure because this structure is thermodynamically stable in this medium [3]. Since, nevertheless, the present beings exist in their present environments, where they are not thermodynamically stable structures, the possibility of a special method or of an artificial medium, where the constituents organize themselves, cannot be evoked.
Then, we must conclude that, contrary to what happens for these organelles and viruses, neither the structure of the present living being, nor its occurrence in its present environment, are explained only by a process of self-assemblage by the reactions and interactions of its constituents one with another and with some elements of its environment. If the impossibility of calculating the structure of the ribosome from its constituents derives only from the lack of an adequate method, it would not be the same for the total living being.
We can raise as an objection, that the cases of the ribosome (or of the virus) and of the total living being are not comparable, the first being a static structure at stability, while the second is a system far of the thermodynamic stability. The problems of their formation (and of their preservation) are quite different, and this difference must be considered in the physico-chemical explanation of the living being. Nevertheless, this consideration does not resolve the incongruous physico-chemical aspect of the present living being in its present environment, and the ontological obstacle remains under the methodological difficulties.
When the living being is changed into a closed system, by the suppression of the exchanges with its environment, it dies and its structure disorganizes itself spontaneously into its separated constituents. The living being can exist only in an uninterrupted flow of matter and energy; its structure is maintained (and developed, and reproducing itself) only at this cost. The second principle of thermodynamics is well respected because of such a flow and the opening of the being to its environment; but, neither this flow, nor this opening can be invoked for the explanation of the present living being in its present environment.
All this, because the being is not “secondary” to this flow, in contrast to other structures (called “dissipative”) which appear spontaneously in flows (as the Bénard’s structures which form theirselves in a liquid in a gradient of temperature). The living structure is not subsequent to the flow (or the gradient): the first creates the second as much as the second produces the first. For the dissipative structures, there is a flow (or a gradient) created by the experimenter, and this flow produces the structures (in return, the produced structure can facilitate the flow, as the convection currents do in the Bénard’s structures). For the present living being in the present circumstances, such a flow (or gradient), in which the living structure would spontaneously appear, does not pre-exist. This structure is produced by its “mother-structure”, and it maintains and develops itself by creating its own flow (there is an active aspect, that is not found in the case of the structures like the Bénard’s cells which are essentialy passive, though they are dynamic). In the case of the Bénard’s structures, the flow creates the structure and explains it; but this flow of warmth is created and maintained by an external factor (the experimenter) who creates and maintains a gradient of temperature, which the flow (and the structure which favours it by the convection currents) tends to annul. In the case of the living being, the flow (nutrition, respiration, excretion) is maintained by the structure itself (which does not participate in the annulment of any gradient, but which tends to reinforce it). Only the first living structure could appear in a pre-existing flow (created by the natural circumstances), but it could subsist only because it undertook this flow (which created it), it maintained it and transmitted it from generation to generation, when the natural circumstances, in which it appeared, have disappeared a long time since.
Therefore, we cannot imagine creating artificially a flow (or a gradient), in which the living structure would appear spontaneously, any more than we can imagine creating an artificial medium in which the dispersed constituents of the being would self-assemble in a structured and functional whole. These energetical factors, flow and opening to the environment, conciliate the existence of the living structure with the second principle of thermodynamics; but they can explain neither the occurrence, nor the structure of the present being in the present circumstances. We can suppose that, as the simple self-assemblage explains the structure of the ribosome, such dissipative structurations explain probably some local structures. But, we cannot induce from this that the total structure could be explained by this means; the flow, in which the living structure exists, is not its cause stricto sensu, as it is produced by the structure and does not exist without it (though it is the flow which allows the existence of the structure) [4].
What is then the explanatory value of biochemistry, since obviously its principles, if they allow local descriptions, do not lead by themselves to a total description, nor to an explanation of the causes of the present living being in its present environment? Does this mean that the being does not respect physico-chemical laws (which are respected by its constituents), and that we must invoke a vital force put over these laws, or a more or less supernatural emergence? Certainly not; the being respects well physico-chemical laws, and does not need any vital force for its explanation. To believe that the fact, that the physico-chemical laws can explain neither the present occurrence, nor the present structure of the being, is derogatory to epistemological materialism, belongs to the already evoked confusion between this materialism and the sciences of matter. To understand it, we must interest ourselves in the relations between structure, occurrence and history in the case of the lifeless object and of the living being.
Previously, we summarize the situation, stating precisely what we have called the ontological obstacle. We have seen above that the principles of self-assemblage or of dissipative structure can be applied to local structures, but not to the total structure. The problem is set at two interdependant levels. First, each local structure, when it is considered as isolated from the others, is explicable (if not explained) by classical physico-chemical laws, while the total structure is not (neither as a structure at thermodynamic stability, nor as a dissipative structure). On the other hand, each relation between the being and its environment, when it is considered as isolated from the other relations, is explicable (if not explained) by classical physico-chemical laws, while the occurrence of the being in its environment (that is to say, its total relation with it) is not (neither as a spontaneous self-assemblage in this environment, nor as a dissipative structure). The first aspect of the problem is the one which is traditionally “solved” by the formula “the whole is more than the sum of the parts”. The second aspect is more paradoxical, since it is equivalent to a system which is not connected to its environment according to classical physico-chemical laws (its occurrence appears as an incongruity in it), while it is opened on this environment and has numerous physico-chemical relations with it (different exchanges of matter and of energy, according to these laws). It is the case of an autonomous system [5].
All this happens as if the total structure becomes its own environment (still remaining opened on which is not itself – cf Bernard’s notion of “milieu intérieur” or internal environment) and creates the conditions of existence of its local structures (a “milieu intérieur”, which allows the ribosome to self assemble; a general flow which allows the existence of local flows, in which some local structures can appear). Local structures are then explained by the total structure, but they do not explain the total structure by their integration.
We meet here the problem of natural organization and finality, as it is studied by Kant in the second part of his Kritik der Urteilskraft [6]. On the one hand, an apparent derogation of the being to the laws which rule its environment, and which can explain neither its structure nor its occurrence in this environment. On the other hand, an organization such as each of the parts seems made by and for the other parts – each of which seems made in the same way –, so that the whole appears as its own cause and its own aim. This peculiar causality, this circularity of determinism, characterizes numerous theories of self-organization of the living being (note nevertheless that, for Kant, such an organization belongs to the reflektierende Urteilskraft [7, 8, 9, 10, 11].
Structure, occurrence and history
The words of structure and history are used in their usual meaning. We understand in the occurrence of the living being its existence, not absolutely considered, but related to its environment: the fact that such a being is present in such an environment.
The problem which this occurrence sets to biochemistry is: how is it possible to explain the presence of such a being in such an environment with physico-chemical principles, when these do not allow by themselves the constitution of the being in the environment?
The objection can be raised that the problem is not peculiar to biochemistry, since physics and chemistry do not explain either the occurrence of a lifeless object only by their laws. For example, the explanation of the occurrence of such and such rock in such and such place requires the account of historical factors, which complete the analysis of the rock by physics and chemistry. It is obvious that such historical factors must be considered in order to explain the occurrence of the living being: but this historical explanation is quite different and more important than the one which is used for the lifeless object.
In the case of the lifeless object, the historical explanation is furnished only by the action, during a certain lapse of time, of physico-chemical laws (which govern the structure of the object and its relations with its environment). Then, the present structure of the object is understood by means of the relations of Its components one with another (and their evolution in course of time) and by its relations with the environment (and their evolution in course of time – especially the evolution of this environment). The present and historical explanations of the structure of the object, and of its occurrence in its environment, are completely bound and interdependent, because the object and its environment form one unit, as much for their present structure as for their evolution. Consequently, the explanation of the present structure of the object (which is bound to that of the environment) is also the explanation of its occurrence in its environment.
The occurrence of the lifeless object (though, like the rock of our example, it cannot be constituted by a self-assemblage or by a flow) does not require any particular explanation, because, on the one hand, the structure of this object is directly bound to that of its environment according to the physico-chemical laws; on the other hand, because the history of its structure and of its occurrence is the direct action of these physico-chemical laws during a certain lapse of time. The structure and/or the evolution of the lifeless object are thermodynamically the most probable in its environment. The historical explanation and the physico-chemical explanation (the explanation by the causes and the explanation by the laws) are quasi-identical.
It does not happen thus within the living being, because, on the one hand, its structure is not directly bound to the structure of its environment according to the physico-chemical laws (hence its incongruous character in its environment), and, on the other hand, because the history of its structure and of its occurrence is not only the action of these laws.
For a clear understanding, it is necessary to look back to the origin of the life. At the time of its formation, the first living entity was such that its structure, its relations with the environment and its occurrence were explicable solely by physico-chemical laws. As a lifeless object, it formed one unit with the environment, where it appeared spontaneously. Indeed, we must say that it became living only when its evolution (at first, individual evolution; afterwards, when it acquires the property of reproduction, the evolution of its descendants) separated it from what became its environment; separation that gives it its aspect of physico-chemical incongruity in this environment, incongruity increasing with the time.
This separation is not the isolation of the entity from its environment (to which it is widely open), but a process that disconnects its individual and specific evolution from that of the environment. For, it is not as much the being itself as its evolution which is autonomous from that of the environment.
Then, the historical explanation of the structure and the occurrence of the pre-sent living being in its present environment takes a quite different form and importance from that of the lifeless object. The action of physico-chemical laws during a certain lapse of time is no more sufficient.
Here, the two aspects of the problem must be well distinguished. On the one hand, the individual and specific evolution of the living being is separated from that of the environment. On the other hand, the living being is not physico-chemically isolated from its environment (openness of the being), but it is not directly related to it according to physico-chemical laws, by the fact they evolve separately (hence, the apparent impossibility of the existence of this being in this environment according to these laws, when the prebiotic phase is finished).
For instance, if we imagine a rock heated to 37°C, and placed in a colder atmosphere, the laws of thermal equilibrium require that the temperature of this rock decreases, until it reaches the ambient air temperature (which, in return, riles up a little). If the existence of a 37°C warm rock in a colder atmosphere seems an incongruity (facing these laws of the thermal equilibrium), which must be explained by a peculiar history (volcanism, exposure to the sun’s warmth,…) in which the physico-chemical laws act, nevertheless the rock is completely bound to its environment by the laws of the thermal equilibrium which govern its cooling.
Now, let us see the case of a seal in Greenland. Considered instantaneously, its 37°C temperature in a cold atmosphere is an incongruity pertaining to the same category that the previously evoked rock. Nevertheless, whereas this rock’s temperature decreases, that of the seal stays constant. Then, the incongruity is of another nature, and it appears only in time.
Now, let us go back in time and pass beyond the point of our first observation: in the case of the rock, the explanation of the 37°C temperature is related to its history, where the physico-chemical laws act directly, a history which is comparable with that of the fall of temperature in the colder air. In the case of the seal, if we wish to explain its 37°C temperature by its anterior history, this history may result only in an incongruity similar to the constancy of its temperature, and not a simple result of physico-chemical laws.
Such an incongruity in the evolution of the temperature does not mean an isolation of the seal, nor a violation of physico-chemical laws. It is well explained by the metabolism of the animal. The seal loses warmth, as the rock does, hut its temperature is maintained constant by a complex physiological apparatus, which compensates this loss (the oxidation of nutrients, productive of warmth), and the thermodynamic balance-sheet of which is perfectly according to the second law. Nevertheless, if the flow of warmth respects the laws of the thermal equilibrium (difference of temperature between the seal and the ambient air), the flow of nutrients and oxygen is not spontaneous, and it is explained only by the pre-existent structure of the seal. In other words, the maintenance of the seal’s structure is explained by a metabolic mechanism, which functions according to the physico-chemical laws, but the structure and the occurrence of this mechanism (the temperature of which is a characteristic which is not only maintained by this mechanism, but also enables this to function) are neither explained by the interactions of its constituents in the actual environment, nor by a history which would be the direct result of physico-chemical laws.
This history can be decomposed into an individual one and a specific one. We know that, in the neo-darwinian conception, the specific history superposes upon the simple action of physico-chemical laws a device, which comprises reproduction, the possibility of mutations in this in other respects unvarying reproduction, arid lastly a selection of some mutant forms according to a criterion, which is the aptitude for life (though such a criterion is insufficient to explain the orientated aspect of global evolution, and though it is necessary to add to it competition between the mutant forms to explain this aspect; the selection of the apter ones for life, and not only of the apt ones) Then, what is superposed upon the simple action of physico-chemical laws is a device, which selects and amplifies some physico-chemical “micro-events” (mutations) at the expense of others. These selection and amplification respect these laws (though the notion of aptitude for life is beyond the physico-chemical level), but they give these “micro-events” an importance which they would never have without that.
In the same neo-darwinian conception, individual history guides the action of physico-chemical laws, by means of a genetic program established by the evolution of species. The reading of this program, its expression, amount to a selection and an amplification, by enzymatic catalysis, of some reactions at the expense of others which are possible with the same substrata, and thus, to give these reactions an importance which they would never have had without that, in simple competition for substrata (as in classic chemistry). This selection and this amplification are, in a manner, the reproduction of the selection and the amplification which “work” in the evolution of species; reproduction which is made possible by their registration in the genetic program.
In both cases nothing is comparable with the evolution of the rock of our example, though the same physico-chemical principles are respected. In addition to pure physico-chemical analysis, biochemistry associates a very particular historical explanation, which is not simply the action of physico-chemical laws during time. Before we study this problem, we will add some remarks to what we said in connection with the character of opened system of the living being and its evolution separated from that of its environment.
The living entity, environment and time
The openness of a living being makes its definition as a physico-chemical entity difficult, by the observer. Obviously, he can refer to the circumscription of the being by a membrane; but, as that membrane is permeable, the delimited entity is not perfectly defined from the physico-chemical point of view (contrary to what happens for the rock the limit of which is the difference of solid/gas phase: if this limit is traversed by exchanges of warmth, it is not traversed by matter; then, the permanence of matter makes it possible to define this rock as a closed system – the choice of the difference of solid/gas phase, to distinguish the rock from its environment, is left to the discretion of the observer, since the rock and its environment make one unity as far as the physico-chemical laws are concerned). If we now refer to the evolution of the rock and of the living being, we become aware of that the distinction rock/environment is quite artificial, because they evolve as one unity, while the being, which, considered out of the time, is completely bound to its environment, to which it is widely open (more than the rock), evolves separately and so distinguishes itself from it (independently of the observer).
If this capacity of constituting itself as an entity distinct from what becomes thus its environment (independently of the observer) is the specificity of the living being, this appears only in time. It is sometimes reproached to the conceptions, according to which the living being is defining itself as a distinct entity, to be static, opposite to the conception of the life as movement and evolution. We see here what must be thought of this criticism: it is in the movement of the temporal evolution (individual and specific) that the living being defines itself. We can quote the expression of H. Bergson, according to whom the form of the living being is “le contour d’un movement”, the outline of a motion [12]. Considered out of time, this being cannot be physico-chemical defined, because it is completely open to its environment and because the observer has no objective character at his disposal on which he could fix a limit. The separation between the being and the environment appears only in temporal evolution; then, the form of the first appears on the background of the latter. And this individualization is not absolute, but relative to an environment; that is to say that the character of entity of the being is not as dependent .on the coherence of the parts (then, the entity would be absolute), as on the movement of separation from the environment (there is an entity only in the relation with what it is not).
This double characteristic of the living entity (it is defined only in time; it is an entity only in the relation with what it is not, and not absolutely, by the simple cohesion of its parts), is often neglected or tackled only with difficulty, not only by biochemistry but also by the diverse theories of self-organization. Nevertheless, it is very important. We remark that, if we wish to have recourse to the notion of emergence, we ought to do it within this framework (and not within that of the appearance of new properties from a certain degree – not specified – of complexity). This emergence would be that of a biological individual, with an identity, from the dialogue of two material masses (the being and its environment) perpetually changing. That individual would extract its identity from the overtaking and the synthesis of the two terms in dialogue. Such an emergence, if we have recourse to it, would be much less magic and much nearer to a dialectic of nature that the one usually evoked.
Can the openness of a being, and the fact that it is individuated only in the movement of its temporal evolution, explain the ontological obstacle to the integration of local physico-chemical descriptions? It appears that, considered out of time (or instantaneously), the being is not a coherent physico-chemical whole: on the one hand, because it is open (and, then, it is not physico-chemically defined as an entity); on the other hand, the fact that it individuates itself only in time and only in the relation with its environment (from which it differenciates itself by the disjunction of its evolution), this fact allows one to think that the physico-chemical relations of the parts one with the others (relations which are exactly of the same nature as the ones which exist between the constituents of the being and those of its environment) are less important for their totalization in an entity distinct from its environment, than the mutual gathering of these parts by the movement of evolution. That is to say that, as the separation of the being from its environment is not truly physico-chemical (the being is physico-chemically bound to its environment by numerous exchanges), also the reunion of the constitutive parts of the being to make a whole is not truly physico-chemical. The movement of temporal evolution, by separating the being from its environment (not physico-chemically, but by making its evolution autonomous from it), groups its constitutive parts in a whole defined by this disjoined evolution. The unceasing movement of individual evolution maintains the parts together, at the same time that it separates their whole from the environment. Then, the not truly physico-chemical character of the gathering of the parts of the being is directly bound to the not truly physico-chemical character of its separation from its environment.
It is obvious that the disjunction of the evolution of the being and of the environment is founded on a peculiar physico-chemical organization (near Kant’s previously evoked notion of natural organization). It is not less true that the being is not a physico-chemically integrated system (nor even integrable); it is a “physico-chemical integration in act”, a never finished integration [13].
The reference to time enables, on the other hand, one to understand better what it means, that the being is physico-chemically bound to its environment, though it is not bound to it according to the physico-chemical laws. The physico-chemical relation is inherent in its openness (and each of the physico-chemical exchanges between the being and its environment respects physico-chemical laws). The “no-relation according to physico-chemical laws” of the global structure with the environment results from its evolution, which is disjoined from that of the environment (but, this disjunction is possible only because the being is an open system and because it can extract from the environment the energy which is necessary for it to maintain and to emphasize its autonomy). To make the being and the environment rejoin one with the other, we must survey the evolutions of the two until the origin of life, when the first living entity appears spontaneously in its environment according to physico-chemical laws. Hence, the great importance of the historical explanation of the structure and of the occurrence of the living being. The recourse to a vital force (or an emergence) to explain its physico-chemical incongruity seems broadly to be owed to the oversight of this historical dimension: the incongruity is only the consequence of the separated evolutions of the being and the environment, evolutions which make the first more and more autonomous from the latter.
Neo-Darwinism and history
We saw above that the structure and the occurrence of a present living being in its present environment cannot be explained only by physico-chemical laws. A historical explanation must be adjoined, which, in contrast to a lifeless object, is not only the simple action of these laws during a certain lapse of time, because the (individual and specific) evolution of the being is disjoined from that of the environment. We saw also, very briefly, how the neo-darwinian conception accounts for this situation by completing the physico-chemical analysis with a double system, which articulates a genetic program and a “mutation-selection” process. Now, we are going to study this neo-darwinian historical explanation.
Neo-darwinian biology is traditionally split in two groups of sciences: the biology of evolution (study of the establishment of the genome) and the biology of development (study of the expression of this genome), which are more or less articulated by genetics (which is itself split into a molecular genetics and a genetics of populations). This divided biology must give two explanations — physico-chemical and historical — for each of the facts which it studies: each of them (isolated from the others) is physico-chemically described, but its occurrence is explained (with that of the being) by the evolution of species. This double explanation seems then complete.
Nevertheless, the difference of epistemological status of the two explanations must be underlined. The one belongs to the physico-chemical sciences, and can aspire to the same scientificity as these. The other belongs to history and to its accidents; then, it cannot aspire to be a science by the same right (without the necessity to invoke Popper’s criterion of falsifiability here). Obviously, this lack of scientificity is not synonymous with untrue, and the explanation given by the biology of evolution is perhaps quite exact (it is evident that the reality of the evolution of species is undeniable, though the explanation given by neo-darwinism has not an absolute scientificity). That is a fairly prevalent opinion, according to which the assured epistemological status of biochemistry results from its analytical and experimental method based on classical physico-chemical laws, whereas a certain haze is admitted for the scientificity of the theory of evolution, for which improvement is sought (see the attempts of M. Kimura, S.J. Gould,…).
Against this view, the objection can be raised that, as we saw above, biochemistry ‑ if it gives local descriptions, the interest of which is acknowledged ‑ has an explanatory value only within the history described by the theory of evolution (and the theory of the genetic program). Then, there is not a physico-chemical explanation of living beings with a certain epistemological status, and a historical explanation with an uncertain epistemological status. But, there is an explanation of living beings, which associates a series of local physico-chemical descriptions and a historical explanation. The two parts of the theory are dependent on each other; and the epistemological status of the whole theory is the status of the feeblest link. This does not mean that the explanation by this whole theory is untrue, but that the epistemological status of biochemistry is not as sure as it seems at first. This apparent assurance is mainly based on the dissociation of biochemistry from the biology of evolution, and on the transfer of everything that would contest the epistemological status of biochemistry, to the biology of evolution (the status of which is sacrificed). The success of this neo-darwinian theory of evolution would result less from its explanation of evolution (see the “improvements” which are unceasingly proposed) than from its capacity to absorb everything that disturbs biochemistry and that would be able to contest its epistemological status.
Such a proposition is in opposition to the common opinion, according to which the certain epistemological status of biochemistry would result only from its analytical and experimental method based on classic physics and chemistry. Also, we would like to point out that we do not contest what is so based in biochemistry: namely the description of local structures and processes. These analyses are beyond all question, as much from the scientific point of view as from the epistemological one, when we consider it at the physico-chemical level, where its implementation is quite correct as an experimental science. What we would wish to debate is how this scientificity is obtained, what is the epistemological cost that is paid to enable such local physico-chemical descriptions to be given, and to present them as explanatory.
For this, we must disentangle how neo-darwinian theory articulates these physico-chemical descriptions one with another, and with the historical explanation of evolution.
Though it never poses the problem explicitly, the neo-darwinian theory explains the integration of the local physico-chemical descriptions by connecting all of them, more or less directly, with a genome supposed to work as a program. In the face of the difficulty of making such an integration, which would explain the being according to exclusively physico-chemical laws (which is the acknowledged aim of biochemistry), it articulates these descriptions with a genome, which is a sort of materialized past, a past to which a physico-chemical form is given, so that it may intervene in the physico-chemical explanation.
This materialized past, this physico-chemical memory, is then the means of making the historical explanation (understood as the establishment of this genome during the evolution of species) enter the physico-chemical explanation; or, more exactly, the means of giving the historical explanation a physico-chemical aspect, which enables one to connect the local physico-chemical descriptions with each another, and to make an amalgam, the epistemological status of which is assimilated with that of physics and chemistry and of the experimental sciences (though indeed this historico-physico-chemical explanation cannot proof it by it, but only the local descriptions).
The theory of the genetic program substitutes to an historical explanation an explanation in terms of the theory of information: if the structure and the occurrence of the present being in its present environment cannot be explained only by means of physico-chemical laws, it is because the being is supposed to possess an informative principle (a sort or formative force) superposed over these laws, the action of which is orientated. To remain within the framework of epistemological materialism, this informative principle is assimilated with a local structure, which has peculiar properties (which are called sometimes the autocatalytic and heterocatalytic functions of the gene). It is not less true that, since recourse to the notion of genetic information results from the impossibility of explaining the present being in its present environment according to physico-chemical laws only, the materialization of the informative principle is not sufficient to give the theory of genetic program an epistemological status comparable to that of the physico-chemical sciences. We cannot have recourse to the notion of genetic information to supplement the insufficiency of the physico-chemical principles in the explanation, and, at the same time, claim the epistemological status of the physico-chemical sciences for the resulting explanation. Biochemistry does not give a physico-chemical explanation of the living being, just because it grants a material character to what it presents as an informative principle. If the observer can think of the genome as bearing genetic information, this genome works in the cell only as desoxyribonucleic acid, only by its physico-chemical properties (and these do not explain the structure and the occurrence of the being in its environment, either as a structure at the thermodynamic stability, or as a dissipative structure). The explanation by the theory of information is mainly a verbal explanation.
The explanation, which suggests that the living being is constituted by the expression of a program established by the evolution of species, is only a substitute to explain the occurrence of the present being in the present circumstances by historical factors, and to give the historical explanation a physico-chemical aspect (which enables it to be articulated with local physico-chemical descriptions, and to articulate these one with another). Yet, this articulation of the historical explanation with the physico-chemical explanation remains inadequate and verbal (what is showed by the difficulties of establishing the thermodynamic status of the living being). The fault is probably that a mistake is made about time in this theory. The notion of inscribed informations allows one to almost eliminate physical time (this elimination is the principle of memory), and to reintroduce it by means of supposed “biological clocks” or by the time of a program, since its absence is too embarrassing (because the simple time of physics and chemistry – the time of action of their laws – is not sufficient to explain the being) [14, 15].
The simplest and most evident illustration of the elimination of the active aspect of physical time, is the oversight of the role of individual evolution in the gathering of the parts into a whole and in the individuation of the being in relation to its environment. And this oversight, though this process is doubtlessly one of the main points in biology, since it explains the specificity of the living being: its capacity to constitute itself as an entity distinct from what is thus becoming its environment. This specificity disappears from biochemistry; the notion of life itself becomes a quasi-metaphysical notion, which must be rejected from the truly scientific work (would not such an attitude belong to what René Thom called the “DNA-mania” – an obsession by the supposed genetic program to such a degree that it hides the basic data of biology? [16].
Another simple and evident aspect of the elimination of physical time in its active dimension is the manner of explaining the establishment of the genetic program. At first, any creative aspect of the temporal dimension is rejected in the evolution of species, in the establishment of the program; then, the being can only reproduce what has been inscribed in that way. Besides, in this evolution of species, the creative aspect is reduced to “pottering”, to a succession of accidents approved by selection. More than mutations (which occur at random), selection (which chooses and amplifies the effects of the mutations in the population) is the true creation of new structures; now, it is just here that the explanation is very verbal, since it invokes a quasi-tautological argument: the advantage facing the selection – the mutant form is selected, because it is more fit to live; it is more fit to live, since it is selected. (The fitness for life may be the capacity of the being to maintain its distinction from the environment in competition with other beings, or such a reproduction that the descendants are more numerous than those of the other beings. In the first case, the argument is directly tautological. In the second case, the better reproduction may be a better capacity of. the descendants to maintain their distinction from their environment (and the argument is directly tautological) or a greater rate of multiplication (and it is not an interesting factor in an evolution, which would select only such mutant forms – the other choosen mutant forms belong to the first case: the better capacity to maintain their distinction from their environment), then the argument is only quasi-tautological).
The principal interest of neo-darwinism, in the “physicalist” view of the modern biology, is that the historical explanation, which it gives, does not superpose upon the physico-chemical laws any principle of an other nature, though it is not the simple action of these laws during a certain lapse of time. It does not superpose upon them any law which would be purely historical and, consequently, different from the natural physico-chemical laws (with which it would have to be articulated in a coherent explanation). Indeed, the theory has recourse only to chance and selection. Now, chance does not obey laws (the laws of probabilities are artifices of calculation, rather than natural laws); mutations have no other explanation beside physico-chemical ones, and selection is made tautologically. Therefore, the theory does not surimpose any principle upon the physico-chemical laws, except that of fitness for life (but it is tautologically defined); it is content with choosing among the different possibilities given by the action of the physico-chemical laws, and with amplifying what is choosen. Hence, economy and simplicity; the historical dimension is reduced to a succession of accidents; its articulation with the action of the natural physico-chemical laws sets no more problems.
We may point out that this is a process quite comparable with the one where different tests are made at random, and where only the ones which are conclusive are retained; that is to say pure empiricism. Hence, it is possible to join Darwin to the English philosophical tradition, which is essentially empiricist (Bacon, Locke, Hume,…). Evolution, considered as a progress of the adequacy of the living being for the environment (an increasing adaptation or adaptability), is then compared to a purely empiric knowledge of the environment, knowledge which is increased by haphazard experiences.
Modern biology can thus assert that it explains the living being by having recourse only to the classic physico-chemical principles (though indeed they are insufficient), because it reduces the historical explanation, which must complete these, to simple empiric “pottering”. The criticism, which can be made here, is purely epistemological and not scientific. However tautological its principle is, the selection by the elimination of the forms inappropriate (or poorly appropriate) for living is an incontestable and scientifically admissible process (even though it is epistemologically questionable). Is it sufficient to explain evolution? That is an unsolvable question (infalsifiable, according to the Popper’s conception).
The other aspect of neo-darwinism, the theory of the genetic program, does not pose the same problem and does not give rise to the same criticism. Here, the “physicalisation” of the living being by the elimination of the historical dimension (in that it is not reducible to the time of classic physics) proceeds by superposing the time of a program upon the time of classical physics. But, therefore, a not strictly physico-chemical principle is associated with the action of the physico-chemical laws: an informative principle, whose materialization is not sufficient to make it a physico-chemical principle (see above).
Here, the criticism is not only epistemological; it is also scientific: it is a scientific fact that the explanation of the occurrence, structure and development of the being by the theory of information is purely verbal (the presence of the genome is not sufficient to explain the present living being in its present environment, either as a structure at thermodynamic stability, or as a dissipative structure). Such a structure and such an occurrence seem to be explained only by a morphogenetic dynamics [17, 18] (the entity exists only by the movement of its temporal evolution disjoined from the one of its environment; this movement creates the form of the entity: morphogenetic dynamics). The genome, rather than a program, would be a kind of “bank of data”, from which the morphogenetic dynamics draws, and by which it is thus guided. The properties of the genome (and of enzymatic catalysis), which are shown by biochemistry, are not contested; but, the genome would not be an omnipotent program; it would put in second place, behind the morphogenetic dynamics, in the service of which it would be (but, which it would orientate in return). It still remains to know whether this relegation of the genome in the second place, in the explanation of the structure and occurrence of the living being, would have repercussions throughout the explanation of evolution, and especially in Weismann’s dogma of the distinction of a germen and a soma. If the darwinian selective conception evokes an empiricist philosophy, this morphogenetic dynamics recalls Lamarck’s tendency to an increasing complexity, and the French rationalist philosophical tradition.
Let us specify it once more: it is not a matter of contesting the reality and the importance of the results of the biochemistry in their purely physico-chemical characters, but only the framework within they are interpreted. A framework which, nowadays, though it has been very useful, sterilizes any development of biology as a science autonomous (but not separated) from physical and chemical sciences (a science which would study how an entity can constitute and distinguish itself from what thus becomes its environment; a science which would study the necessary properties of such an entity). The unique development, which seems possible in the theory of the genetic program, is the multiplication of the feed back regulations in the expression of the genome, a development which is rather a growth, and which is unable to explain the specificity of the living being (as the Ptolemaic geocentric system could only grow by the multiplication of the epicycles and remained constitutionally unable to explain the physical nature of the movement of the heavenly bodies).
As far as the principle of the explanation of the structure and the occurrence of the living being by genetic information inscribed in a program is admitted (even though we do not know generally how to pass from the information to the structure – from the genotype to the phenotype –, except for the explanation of the presence of one or another substance), biochemistry can transfer to the biology of evolution (the epistemological status of which is sacrificed) everything which brings difficulties for classical physics and chemistry (and which is often related to time), by imputing it to an information established by evolution’s pottering. Without speaking of such abuses as those which suppose genes for every- and anything (see, for example, the genes of death [19]: when will it be explained that such genes have been selected because they favoured the beings which possessed them?). Due to this transfer, biochemistry can progress rapidly and brilliantly within the framework of physics and chemistry, with the epistemological guarantees of these sciences and with that of the experimental method, In return, biochemistry presumes on this rapid and brilliant progress to justify its principles and to consolidate the darwinian theory of evolution, which absorbs everything which embarasses it and, thus, enables its brilliant progress. This theory of evolution, the status of which is nevertheless uncertain (it is not our purpose to contest the reality of evolution, but to criticize its explanation), is then established as a scientific truth, by the successes which it allows to biochemistry (at the very time when these successes are possible only by transfering the difficulties to the theory of evolution).
This leads to a quite perverse epistemological situation, of which numerous biochemists make use and abuse. They have no sufficiently strong invectives for anybody who ventures to contest the process (they invoke the experimental method, they claim that such a criticism is vitalistic,… though they know very well that almost nobody contests the necessity of epistemological materialism, that almost nobody has recourse to a vital force, and that the results of biochemistry are almost universally accepted as physico-chemical descriptions and contested only when they are incorrectly generalized) [20]. As the problem is very complicated, as the solution given by neo-darwinism theory is easily understood in terms which are the ones of scientific popularization (rather than the ones of scientific theory or of epistemology), and as it adapts itself well to a certain haze when one attempts to deepen the problem, such a situation can last for ever (more especially as this theory has been plentifully spread through the media).
We may nevertheless hope that a critical treatment will lead biochemists to understand that their results will not be lessened if, rather than to stick to an unceasingly fissured and unceasingly replastered pattern of thought, they participate in the elucidation of the mechanism of the individuation of the living being, the mechanism of the disjunction of its (individual and specific) evolution from that of the environment (in one word, the elucidation of the specificity of the living being comparatively to the lifeless object) in a collaboration with theoricians and epistemologists.
André Pichot
Researcher at the CNRS in epistemology and history of science.
Paper published in
Fundamenta Scientae, 8 (1), February 1987.
Acknowledgments
My best thanks to Mlle Isabelle Stengers, who granted me her critical reading of the first version of this article. I thank also Mme T. Paris and Mlle C. Kormann who corrected its English translation.
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