In this section, I will present another perspective on values in the life sciences, the one proposed by Georges Canguilhem. His work presents three aspects that are difficult to separate: medical philosophy, history of biology and philosophy of science. Jean Gayon observes that if the first two aspects are relatively well known, “in terms of the philosophy of science, and especially the philosophy of life sciences, until recently Canguilhem was almost completely unknown among American scholars” (Gayon, 1998, p. 305). Indeed, Canguilhem can hardly be considered as participating in the debate in the domain of the “philosophy of biology”, referring to the Anglo-Saxon tradition starting from the late 1960s; he rather used the expressions “biological philosophy” or “philosophy of life sciences” to characterize his own work (Gayon, 1998). However, several scholars have recently highlighted the fecundity of Canguilhem’s philosophical thought. The book Vital Norms: Canguilhem’s The Normal and the Pathological in the Twentieth Century (Méthot and Sholl 2020) is particularly interesting with this respect. The collection of contributions proposes fresh perspectives to read Canguilhem’s work by exploring its historical, philosophical, and social dimensions.Footnote 6
Although it will not be possible to give an exhaustive presentation of Canguilhem’s rich contribution to philosophy of life science, I shall here present some key points concerning the centrality of the question of values in his thought.
Main thesis of the Essay on some problems concerning the normal and the pathological (1943)
Very early in his work, the question of values and norms appears to be central in Canguilhem’s philosophical thought (Limoges, 2015, p. 34). In his book Essay on some problems concerning the normal and the pathological (1943), Canguilhem questions the categories of “normal” and “pathological” in the philosophy of medicine, claiming that they cannot be considered as descriptive but rather as axiological. Canguilhem shares this thesis with the German neurologist and psychiatrist Kurt Goldstein (1878–1965): the concepts of normality and illness require the concept of “individual being”.Footnote 7 In his book from 1934, Goldstein claims that health, illness and recovery must be understood with reference to the notion of a personal individual norm (Goldstein, 2000).
A clinical argument (Gayon, 1998) is advocated by Canguilhem to support the same thesis as Goldstein in the field of philosophy of medicine: illness cannot be considered as a deviation from the statistical norm, but as the emergence of a new individual norm. The point is that, in this new norm related to the condition of illness, the individual is much more fragile with respect to its environment: the capacity to tolerate “the inconstancies of the environment” are reduced (Canguilhem, 1991, p. 197).Footnote 8 The individual in a pathological state is able to live in a specific environment, but this environment is narrowed if compared to the healthy individual. In fact, the healthy individual is “more than normal”, it is “normative”. The concept of “normativity”, at the core of Canguilhem’s biological philosophy, does not only apply to human beings, but to living beings in general.Footnote 9 In the Essay, normativity is referred to as an expression of the “dynamic polarity of life” (Canguilhem, 1991, p. 127), the main idea being that the living is never indifferent to its life conditions:
“Life is far removed from such an indifference to the conditions which are made for it; life is polarity. The simplest biological nutritive system of assimilation and excretion expresses a polarity. When the wastes of digestion are no longer excreted by the organism and congest or poison the internal environment, this is all indeed according to law (physical, chemical, etc.) but none of this follows the norm, which is the activity of the organism itself. This is the simple fact that we want to point out when we speak of biological normativity.” (Canguilhem, 1991, p. 127–128).
Thus, biological normativity can be understood as the ability of the organism to produce or establish a way of living in a given environment (Sholl, 2020). The normative organism has a flexible relationship to the environment and it is capable of tolerating the potential “inconstancies of the environment” (Canguilhem, 1991, p. 197). In contrast, the pathological organism expresses another kind of norms of life: “these norms are inferior to specific earlier norms in terms of stability, fecundity, variability of life” (Canguilhem, 1991, p. 197).Footnote 10
The role of evolution and natural selection in Canguilhem’s reasoning
As pointed out by Jeler (2014) and Méthot (2020) it is striking that, to discuss the categories of normal and pathological, Canguilhem always refers to the question of the evolution of species and the concept of natural selection. What is the link between the thesis that the pathological cannot be defined as a deviation from statistical norm and evolutionary issues? This challenging question has been tackled by Jean Gayon (Gayon, 1998) and more recently by Pierre-Olivier Méthot (Méthot 2020).Footnote 11
The main point that interests Canguilhem is that, in the Darwinian theory, organic variability is at the very basis of the evolutionary process. In a population, between all possible variations, some organisms may present mutations that are deviations from the statistical norm. Already in the forties, when writing the Essay, Canguilhem was already interested in the experimental work on natural selection by the French biologist Georges Teissier. Canguilhem finds in Teissier’s work the empirical confirmation of the fact that statistical anomalies (deviations from statistical norms) should not be regarded as pathological from the outset. In some contexts, where the mutation happens to be viable, statistical anomalies could be at the origin of a new species. This can be easily understood from the Drosophila experiences performed by Georges Teissier and Philippe l’Héritier. The two biologists have observed that certain mutations, which can seem disadvantageous in a species’ environment, can become advantageous if the conditions vary. In a sheltered and closed environment, Drosophila with vestigial wings are wiped out by Drosophila with “normal” and functional wings. But Teissier and L’Héritier created experimental conditions in an open and windy environment, in which Drosophila with vestigial wings “do not fly, feed constantly, and in three generations we see sixty percent vestigial Drosophila in a mixed population” (Canguilhem, 1991, p. 142). Thus, Drosophila with vestigial wings become “normal” in the new environment. The notions of normality and abnormality are meaningful only with respect to the relationship between the organism and the environment. Twenty years after the Essay, in the “New Reflections on the normal and the pathological”, Canguilhem would be still reasoning on these issues and defining the norm as “the kind of deviation that natural selection maintains”.Footnote 12
Organic variability and the question of values
How does this reasoning on evolution and natural selection relate to the question of values? This question is clearly answered, I think, in the text from 1951 “The normal and the pathological”, published in The Knowledge of Life (Canguilhem, 2008). As Gayon (1988) remarks, the key point is the inseparability between the notion of organic variability and the problem of biological value.
“Individual singularity can be interpreted either as a failure or as an attempt, as a fault or as an adventure… as attempts or adventures, living forms are considered not beings referable to a real, pre-established type but organizations whose validity (that is, value) must be referred to the eventual success of their life.” (Canguilhem, 2008, p. 125).
Here Canguilhem claims that the “value” of an organic form must be referred to the eventual success of their life. He also remarks, a few lines later, that there is an identity between “value” and “health” (in Latin, valere means “to be well”). However, the success of an organic form cannot be anticipated a priori and it is always temporary and threatened:
“There is no in itself a priori difference between a successful form and a failed form [forme manquée]. Properly speaking, there are no failed forms. Nothing can be lacking [manque] to a living being once we accept that there are a thousand and one different ways of living. Just as in war and politics there is no definitive victory, but only a relative and precarious superiority or equilibrium, so in the order of life there are no successes that radically devalorize other attempts and make them appear failed. All successes are threatened, since individuals and even species die. Successes are delayed failures; failures are aborted successes. What decides the value of a form is what becomes of it.” (Canguilhem, 2008, p. 126).
If the value of an organic form is its temporary “success”, what is the connection between values and natural selection? Selection is the sorting or screening done by the environment:
“…We must note that different genotypes—the lineages of a given species—present different “values” in relation to ambient circumstances. Selection, that is, screening by the milieu, is sometimes conservative in stable circumstances and sometimes innovative in critical circumstances. At certain times, "the riskiest attempts are possible and licit."” (Canguilhem, 2008, p. 127).
The relationship between the concept of natural selection and question of values is still discussed in a text published in 1977 (“The question of normality in the history of biological thought”), where Canguilhem analyses the work of Darwin. Canguilhem claims that, even if the mechanism of natural selection is non-teleological, this does not mean that Darwin has eliminated from the idea of life every reference to a “comparison of values” (Canguilhem, 2009, p.166, my translation). The sorting by natural selection gives, as a result, the adaptation of organic beings. If Darwin has detached the concept of “adaptation” from that of a preordained purpose, he has conceived adaptation with respect to “normality”.Footnote 13 The result of a non-teleological mechanism are beings whose life is “a difference of value with respect to death”.Footnote 14 The normality of a living being is “that quality of its relation to the environment that enables it to generate descendants exhibiting a range of variations and standing in a new relation to their respective environments, and so on.” (Canguilhem, 1988, p. 137).Footnote 15
The active role of the organism with respect to the environment
In Sect. 3.3, I have discussed organic variability meaning with this term “inter-individual” variability. In that sense, natural selection can be seen as sorting out individuals that have inherited valuable variationsFootnote 16: this would suggest that the environment determines the organisms that will be viable. But an additional feature, central to Canguilhem’s reasoning, introduces more complexity to this picture: the organism cannot be considered as being merely passive with respect to the environment. This is clear for Canguilhem already in the Essay, where he states in the conclusion:
“Types and functions can be qualified as normal with reference to the dynamic polarity of life. If biological norms exist it is because life, as not only subject to the environment but also as an institution of its own environment, thereby posits values not only in the environment but also in the organism itself. This is what we call biological normativity.” (Canguilhem, 1991, p. 227, italics added).
This is developed in 1946–47 with Canguilhem’s idea of the organism as “center of reference” of values, which appears clearly in “The living and its milieu”. An organism, whether we are talking about a man, a plant or an amoeba, is never indifferent to its life conditions, it appreciates what is good or bad for itself (e.g. some physical condition, some food resource).
“Biology must first hold the living to be a significative being, and it must treat individuality not as an object but as an attribute within the order of values. To live is to radiate; it is to organize the milieu from and around a center of reference, which cannot itself be referred to without losing its original meaning”Footnote 17(Canguilhem, 2008, p. 113–114).
An excerpt from “The living and its milieu” is particularly helpful to clarify this question of values relating to both organisms and the environment. While discussing the differences between the notion of environment in Lamarck and Darwin, Canguilhem writes:
“In any case, for Darwin, to live is to submit an individual difference to the judgment of the ensemble of living beings. This judgment has only two possible outcomes: either death or becoming oneself part of the jury for a while. So long as one lives, one is always judge and judged.” (Canguilhem, 2008, p. 105).
It is worthy to conceptually distinguish this double aspect of the organism being both “judge” and “judged”. For Canguilhem, so long as an organism live, it is judged (by the environment) but at the same time it judges by reacting actively to it. The organism judges because it is never indifferent to its environment and it assesses (although unconsciously, except in the case of man) what is positive or negative for its life. There is a “debate” between the organism and the environment, “to which the living brings its own proper norms of appreciating situations, both dominating the milieu and accommodating itself to it.” (Canguilhem, 2008, p. 113). This debate takes the form of a strong opposition for the pathological individual, whereas for the healthy individual it seems to be somehow a “soft” opposition.Footnote 18 So long as the organism succeeds in coping with the environment (whether in a healthy or pathological situation, the point being to stay alive), it is also to some degree “member of the jury”. Indeed, the organism will be part, for a while, of the organic component of the environment (for example, we can imagine the case of an organism X acting as a competitor for an organism Y). At the same time, the organism is “judged”. The norms of the organisms are “sorted” by the “environment”: natural selection is understood both with its organic and inorganic components. In the experiments of Teissier and L’Héritier, Drosophila are “judged” by abiotic conditions (windy or sheltered). However, the “judgement” could also come from other organisms being members of the jury (competitors, predators, etc.) Although it is useful to distinguish them conceptually, these two aspects of “judge” and “judged” seem to be conceived by Canguilhem as two sides of the same coin. Ultimately, a physiologically well-adapted organism that can cope with its environment will be “positively sorted” in the evolutionary process.Footnote 19
A last point is worthwhile to mention with respect to the idea of the organism not being passive with respect to the environment. As Sholl (2020) has pointed out, Canguilhem not only considers the organism as being “constructive” with respect to the environment, but also as presenting a certain “plasticity”. The idea is that the problem of biological variability has to be understood not only with respect to inter-individual variations, but also with respect to intra-organismic variability (see Sholl, 2020). Variability within the individual may be expressed through developmental or phenotypic plasticity or, in some organisms, by varying their behaviours. For Canguilhem variability is always “good”, because it is the only thing that guarantees the “promptness” of the living in reacting to the possible changes of the environment. In the New reflections on the normal and the pathological, Canguilhem also notes that this is also true for variability considered at a more general scale. In fact, if we consider the whole of living beings “in the continuity of life”, we see that there is a “variation of modes of life for the occupation of all vacant places” (Canguilhem, 1991, p. 263). Thus, variability can be regarded as “good” at least at three different levels: at the level of the organism (developmental or phenotypic plasticity, behaviour), at the level of the lineage (inter-individual variability) and at the level of “modes of life” (variability of ecological strategies).