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Ernst Mayr: This is Biology:
the science of the living world
(Belknap/Harvard:1997)


“More and more clearly, Ibegan to see that biology was a quite different science from the physical sciences; it differed fundamentally in its subject matter, its history, its methods, and its philosophy. While all biological processes are compatible with the laws of physics and chemistry, living organisms could not be reduced to these physiochemical laws, and the physical sciences could not address many aspects of nature that were unique to the living world. The classical physical sciences, on which the classical philosophy of science was based, were dominated by a set of ideas inappropriate to the study of organisms: these included essentialism, determinism, universalism, and reductionism. Biology, properly understood, comprises population thinking, probability, chance, pluralism, emergence, and historical narratives. What was needed was a new philosophy of science.”
(Mayr, p.xiii)

And thus, perhaps the greatest of living biologists introduces the conceptual bases of his discipline...which he, perhaps more than any other, has done so much to clarify and promote. We would do well to pay him heed, particularly given that the contemporary general understanding of this area is so heavily skewed toward genetics and the modeling of population biologists, who also (and invariably) happen to use drastically simplified - and clearly falsified - assumptions re gene activity, a fact little known to most of their lay audience. By clearly insisting upon the intractable pluralism of biology as a whole, and through tracing the intellectual history of some of its key strands, Mayr delivers us a crucially whole perspective upon this most varied of disciplines, and one with profound implications for its (unnecessarily fraught) relation to the humanities.

For those of you who don’t know, Ernst Mayr is the last surviving key player in the creation of the modern synthesis - or neodarwinism, as it is better known. His contribution was that of reformulating taxonomy and related disciplines (the rootstock of scientific biology) into systematics...reconciling its techniques and assumptions with the emerging synthesis of Darwinism and genetics and, as in all of the other key stages of the synthesis, then prompting shifts in these areas as well. For this intellectual movement was hardly the surrender to population genetics that some of the latter’s more extreme proponents appear to have assumed. Rather, the accommodation was mutual, as Mayr has repeatedly insisted, and - although key areas such as development were not included, largely due to the paucity and intractable complexity of the evidence then to hand - the result was a stunning success, on both practical and intellectual grounds.

Much later in his career, Mayr gradually began to concentrate upon the philosophy and history of biology, culminating in the magisterial Growth of Biological Thought in 1982, to be followed by a series of shorter - and, in the main, more accessible - works, following up on different aspects of this, in which the book under review here is the third and, perhaps, the most important. It is this unequaled background which makes his such an authoritative voice, despite being little known to the general public...and, therefore, if you want to know what biology actually is - as opposed to the partisan claims of certain celebrated specialists - this is definitely the book to turn to. And, as we shall see, the reality is that the humanities has much more in common with its scientific neighbor than most suspect...


“The incorporation of biology has modified many of the tenets of the philosophy of science.... The rejection of strict determinism and of reliance upon universal laws, the acceptance of merely probabilistic prediction and of historical narratives, the acknowledgment of the important role of concepts in theory formation, the recognition of the population concept and of the role of unique individuals, and many other aspects of biological thought have affected the philosophy of science fundamentally. With probabilism now dominant, all aspects of logical thought that are based on typological assumptions have become highly vulnerable. The complete certainty which, following Descartes, had been the ideal of the philosophers of science seems less and less important as a goal.”
(Mayr, pp.36-7)

“Those who have a high regard for natural laws are mostly thinking about the regularities of nature.... [However,] regularities are abundant in the living world, too, but most of these regularities are not universal and without exception; they are probabilistic and very much restricted in space and time.... In biology, concepts play a far greater role in theory formation than do laws.... In evolutionary biology, for example, they include selection, female choice, territory, competition, altruism, biopopulation, and many others. Concepts, of course, are not restricted to biology.... I have the impression, however, that the number of basic concepts is rather limited in the physical sciences, and in such fields of functional biology such as physiology, where the discovery of new facts is very important.... The classical philosophy of science has made curiously little reference to the important role of concepts in theory formation. The longer I study theory formation, however, the more I am impressed by the fact that theories in the physical sciences are usually based on laws, those in biology on concepts.”
(Mayr, pp.62-3)

“As far as the demarcation between science and the humanities is concerned, the tendency of writers in the past to ignore the heterogeneity of both fields has led to many misconceptions. There is more difference between physics and evolutionary biology - both of which are branches of science - than between evolutionary biology (one of the sciences) and history (one of the humanities).... In other words, the sharp break between the ‘sciences’ and the ‘nonsciences’ does not exist, once biology is admitted into the realm of science.”
(Mayr, pp.37-8)

That this is, still, a controversial view - rather than a simple truism - is due, I feel, to incomprehension on both sides, to a large extent driven by ill-informed polemics rather than real understanding. It’s also worth noting that the much better informed approach has been largely driven by historians - from Marc Bloch to John Lewis Gaddis - on the humanities side, and by natural historians - rather than laboratory biologists - on the other. For it is they who, invariably, have to deal w/the whole, messy depth of their subjects...and, at that level, the similarities are most obvious...

This is not to say, however, that they are identical, by any means. The differences, driven by interacting  psychological, social and cultural factors, remain crucial to the humanities, and the human sciences. What it does strongly suggest, however, is that the work of doing so should rather naturally build upon a proper understanding of the organismic basics - the territory, of course, of biology. Meanwhile, it’s also remarkable how clearly (and easily) Mayr disposes of those philosophical myths which have traditionally seen historical approaches as basically “unscientific”...yet another reason why this book is such a valuable one for humanists:


“The reason why historical narratives have explanatory value is that earlier events in a historical sequence usually make a causal contribution to later events.... [So] the most important [scientific] objective of a historical narrative is to discover causal factors that contributed to the occurrence of later events in a historical sequence. The establishment of historical narrative does not in the least mean the abandonment of causality, but it is a particularistic causality arrived at strictly empirically. It does not relate to any law but, rather, explains a simple, unique case.”
(Mayr, pp.65-6)

“Causality in simple interactions is often highly predictive.... However, such a simple solution is rarely available in biology, except at the cellular-molecular level. The problem is particularly perplexing whenever the effect is the end of a whole chain of events. It is perhaps a residue of teleological thinking that makes us search at the beginning of the process for the cause producing the predictable end effect. But in biology, this approach is usually not successful; in fact, it is often misleading.... An interaction between two individuals, prior to its conclusion, goes through a whole series of stages, during most of which each of the acting individuals has several options available. Which of these he will choose is not strictly determined at the beginning of the stage, but depends upon a number of factors and contingencies. Strict causality can usually be construed only when the chosen option at each step of the chain of actions is looked at retrospectively. In fact, the whole process (even its random components) can be considered to have been causal when retrospectively considered. One could therefore say, somewhat paradoxically, that causation in complex situations is an a posteriori reconstruction, or, to put it differently, causation consists of a series of steps which, taken together, can be called the cause.”
(Mayr, pp.66-7)

“There is a further complication as far as causation in biology is concerned. Every phenomenon or process in living organisms is the result of two separate causations, usually referred to as proximate (functional) causations and ultimate (evolutionary) causations. All the activities or processes involving instructions from a program are proximate causations. This means particularly the causation of physiological, developmental, and behavioral processes that are controlled by genetic and somatic programs. They are answers to ‘How’ questions. Ultimate or evolutionary causations are those that lead to the origin of new genetic programs, or to the modification of existing ones...They cannot be investigated by the methods of chemistry or physics, but must be reconstructed by historical inferences - by the testing of historical narratives. They are usually the answer to ‘Why’ questions.... Many famous controversies in the history of biology came about because one party considered only proximate causations and the other party considered only evolutionary ones.... [But] when one looks carefully at a biological problem, one can usually discover more than one causal explanation.... Such pluralism of beliefs presents a problem for both verification and falsification.... Curiously, pluralism in biological explanation was much better appreciated by the old-time naturalists than by modern specialists.... [Moreover,] almost every protracted controversy in biology was terminated by the rejection of both previous explanations, and the adoption of a new one.”
(Mayr, pp.67-9)

As the great proponent of what he terms “population thinking” - the accordance of crucial importance to individual variation that modern biology has inherited from Charles Darwin - Mayr is probably the best qualified to correct the anti-biological foolishness of proudly “anti-essentialist” thinkers in the humanities. For, what they clearly don’t realize is that systematic thinking along these lines, although anticipated by Adam Smith, was most thoroughly advanced by Darwin, in biology...making their accusations of “determinism” re biological thinking about 150 years behind the times! Similarly, Darwin also dealt the crucial blow against teleology, thus also undermining the kind of “metanarratives” they oppose. Any good historian of biology could easily tell them this...definitely furthering my already well-founded suspicion that much of this so-called “scholarship” is simply bogus...

One key feature of this book, in fact - a usefully atypical one, today - is Mayr’s robust defense of the descriptive and classificatory base of science...all too commonly sneered at as mere “stamp collecting”. This is perhaps to be expected, with Mayr’s background in systematics, but it is, nonetheless, an extremely important case to make. As he argues, “what” questions have a clear logical priority over “how” and “why” questions - which cannot even be seriously proposed until the proper range of facts are clearly laid out. Moreover, exactly how those facts are to be classified is, itself, a crucial intellectual task:


“Every classification system has two major functions: to facilitate information retrieval and to serve as the basis for comparative research. Classification is the key to the system of information storage in any field.... Classifications are heuristic systems.”
(Mayr, pp.125-6)

Another of the (many) pleasures of this book - albeit one which is necessarily under-represented in this review - is Mayr’s encyclopedic knowledge of the history of biology, most evident in those chapters outlining the growth of understanding in various key subdisciplines. This allows him to get to the core...not only of key historical disputes, but also of their modern counterparts, and to advance some highly insightful conclusions which could provide much-needed lessons for us all:


“The reasons why some theories have to struggle for the better part of a century before they are accepted, while a few new ideas succeed almost instantaneously, are manifold; I will list six of them. One reason that consensus takes a long time to achieve is that different sets of evidence lead to different conclusions.... A second reason...is that disagreeing scientists adhere to different underlying ideologies, making certain theories acceptable to one group which are impossible for another group.... The replacement of ideologies (‘deep paradigms’) meets far more resistance than the replacement of erroneous theories. Such viewpoints such as vitalism, essentialism, creationism, teleology, and natural theology were an essential part of the worldview of those who held them, and were not easily given up. Opposing concepts therefore spread only slowly, by recruiting adherents who did not yet have a firm worldview. A third reason is that at a given time, several explanations may seem to account for the same phenomena equally well...[or,] in some cases, there is actually a pluralism of possible answers.... Sometimes a consensus cannot be reached because one biologist is concerned with proximate, the other with evolutionary causations.... [And finally,] some factors that work against the acceptance of new ideas are not strictly scientific.... Presumably in these cases one of the other five reasons above was primary, but once a tradition was established it was tenaciously maintained even in the face of all opposing evidence.”
(Mayr, pp.102-4)

To these, however, I feel we should add two that have clearly played an important part, particularly in disciplines where, respectively, mechanism and mathematical modeling have served as the gold standard. The first is where, although factual evidence appears to converge upon some outcome, no plausible mechanism which could account for it has yet been proposed, as in the case of continental drift in geology. The second, and much more serious problem - as it so evidently leads to theoretical ossification - is where mathematical tractibility, rather than the evidence per se, serves as the justification for the dismissal of more factually-based theories, usually pluralistic, which are not so easily (or at all) modelled. Population biology - with its extremely unrealistic “beanbag genetics” assumptions - is clearly the main offender here in the life sciences. Admittedly, one could - at a stretch - incorporate these within Mayr’s typology (under classifications one & two, perhaps), however I feel that, due to both their prominence and persistent recurrence, they amply deserve separate status.

The first book by Ernst Mayr that I encountered, well over a decade ago, was One Long Argument: Charles Darwin and the Genesis of Modern Evolutionary Thought which, to my mind, is an exemplary work in the history of ideas - demonstrating the strongly differential reception of Darwin’s theories, and making clear just how this can be tied to the long-established ideologies which they challenged. For, contra Spencer’s - not Darwin’s - misnamed “Social Darwinism”, his theories seriously (and effectively) undermined some of the crucial shared assumptions of the day - essentialism, teleology, the passive nature of the female - and, aside from the basic fact of evolution as such - had little support until well into this century, with sexual selection only fully established as late as the 1970s. Here, he restates some of the core arguments of that earlier work, and provides a useful corrective to some of the misunderstandings which still bedevil Darwin’s legacy, especially in popular understandings...


“Darwin’s Origin of Species established five major theories relating to different aspects of variational evolution: (1) that organisms steadily evolve over time (this we might designate as the theory of evolution as such), (2) that different kinds of organisms descended from a common ancestor (the theory of common descent), (3) that species multiply over time (the theory of the multiplication of species, or speciation), (4) that evolution takes place through the gradual change of populations (the theory of gradualism), (5) and that the mechanism of evolution is the competition among vast numbers of unique individuals for limited resources, which leads to differences in survival and reproduction (the theory of natural selection).”
(Mayr, pp.177-8)

“Only in recent years have evolutionists fully understood how drastically different Darwin’s theory of evolution through natural selection was from earlier essentialistic or teleological theories. When Darwin published the Origin, he had no proof for the existence of natural selection; he postulated it only from inference. Darwin’s theory was based on five facts and three inferences.... The first three facts are the potentially exponential increase of populations, the observed steady-state stability of populations, and the limitation of resources. From this follows the inference that their must be competition (a struggle for existence) among individuals. Two further facts, the genetic uniqueness of every individual and the heritability of much of individual variation, lead to the second inference, differential survival (that is, natural selection), and to the third inference that a continuation of this process through many generations would result in evolution.... The principle of natural selection is so logical and so obvious that today it can hardly be questioned at all. What can be, and indeed must be, tested in each individual case is to what extent natural selection has contributed to the characteristics of a particular component of the phenotype. For each characteristic, the questions that must be asked are: Was the evolutionary emergence of this characteristic favored by natural selection, and what was its survival value that has led to its being favored by natural selection? This is the so-called adaptional program.”
(Mayr, pp.189-91)

“If natural selection does not necessarily produce evolutionary progress, neither does it produce perfection, as Darwin pointed out...[as] there are numerous limits or constraints on its power to bring about change. First of all, the genetic variation needed to perfect a characteristic may not be forthcoming. Second, during evolution, the adoption of one among several possible solutions to a new environmental opportunity may greatly restrict the possibilities for subsequent evolution...Another constraint on natural selection is developmental interaction. The different components of the phenotype are not independent of one another, and none of them responds to selection without interacting with one another. The whole developmental machinery is a single interacting system...[and so,] organisms are compromises among competing demands.... The structure of the genotype itself imposes limits on the power of natural selection. The classical metaphor of the genotype was of a beaded string...[and] each gene was more or less independent of the others. Not much is left of this previously accepted image. It is now known that there are different functional classes of genes...[and] deciding how they all interact with one another, and particularly, what controls the epistatic interactions between particular gene loci, is still a rather poorly understood area of genetics. A further constraint on natural selection is the capacity for non-genetic modification. The more plastic the phenotype is (owing to developmental flexibility), the more this reduces the force of adverse selection pressures.... Finally, much of the differential survival and reproduction in a population is the result of chance, and this also limits the power of natural selection. Chance operates at every level of the process of reproduction.... Yet over time...relative fitness always plays a major role.”
(Mayr, pp.198-200)

At the heart of Mayr’s account of the history of biology lies the long-running dispute between mechanistic/physicalistic approaches, and those who postulated vitalistic forces...a dispute only resolved after centuries of wrangling. Often understood today as a qualified victory for the former, Mayr clearly explains that this was not at all the case - since physicalist accounts - very like those of the vitalists, actually - relied upon very vaguely specified forces to cover awkward facts, whilst the (scientific, as opposed to mystical) vitalists built up an important body of empirical work in exactly those areas in which narrow physicalist accounts were most deficient. And when, finally, the dispute was resolved, the modern account proved markedly different to both its predecessors:


“When biologists and philosophers speak of ‘life’...they usually are not referring to life (that is, living) as contrasted with death but rather to life as contrasted with the lifelessness of an inanimate object.... The problem here is that ‘life’ suggests some ‘thing’ - a substance or force - and for centuries philosophers and biologists have tried to identify this life substance or vital force, to no avail. In reality, the noun ‘life’ is merely a reification of the process of living. It does not exist as an independent entity.... [And] there was always a camp claiming that living organisms were not really different at all from inanimate matter; sometimes these people were called mechanists, later physicalists. And there was always an opposing camp - called vitalists - claiming instead that living organisms had properties that could not be found in inert matter.... In this century, it has become clear that both camps were partly right and partly wrong. The physicalists had been right in insisting that there is no metaphysical life component, and that at the molecular level life can be explained according to the principles of physics and chemistry. At the same time, the vitalists had been right in asserting that, nevertheless, living organisms are not the same as inert matter but have numerous autonomous characteristics, particularly their historically acquired genetic programs, that are unknown in inanimate matter. Organisms are many-level ordered systems, quite unlike anything found in the inanimate world. The philosophy that eventually incorporated the best principles from both physicalism and vitalism (after discarding the excesses) became known as organicism, and this is the paradigm that is dominant today.”
(Mayr, pp.2-3)

“This new paradigm accepted that processes at the molecular level could be explained exhaustively by physiochemical mechanisms, but that such mechanisms played an increasingly smaller, if not negligible, role at higher levels of integration. There they are supplemented or replaced by emerging characteristics of the organized systems.... According to W.E. Ritter, who coined the term ‘organicism’ in 1919, ‘Wholes are so related to their parts that not only does the existence of the whole depend on the orderly cooperation and interdependence of its parts, but the whole exercises a measure of determinative control over its parts.”...[Hence,] explanatary reductionism is quite unable to explain characteristics of organisms that emerge at higher levels of organization.... To sum up, organicism is best characterized by the dual belief in considering the organism as a whole, and at the same time the firm conviction that this wholeness is not to be considered something mysteriously closed to analysis, but that it should be studied and analyzed by choosing the right level of analysis. The organicist does not reject analysis, but insists that analysis should be continued downward only to the lowest level at which this approach yields relevant new information and new insights. Every system...loses some of its characteristics when taken apart, and many of the most important interactions of components of an organism do not occur at the physiochemical level, but at a higher level of integration. And finally, it is the genetic program which controls the development and activities of the organic integrons that emerge at each successively higher level of integration.”
(Mayr, pp.16-20)

Ernst Mayr’s This is Biology is the work of an aging scholar, profoundly knowledgable about his subject matter, and well able to take that broad view which is so useful to those of us coming to the discipline from the outside. In this, it is almost diametrically opposed to our usual diet of popular science and, although somewhat more difficult to digest, is markedly more nourishing to our understanding. By (rightly) insisting upon the importance of all the key questions - the “what”, the “how”, and the “why” - and by tracing the histories of foundational subdisciplines that concentrate upon these, Mayr is able to show us the very real (and necessary) pluralism of biology as a whole, in a way that is not only relevatory re the task at hand, but which also has many lessons for those of us who labour in other disciplines. Let us just hope that his voice does not go unheard...


“Typological thinking is never enlightening in the study of life, but it has been most vicious and deleterious in the consideration of human races. Modern molecular research has revealed that all so-called human races are very closely related to one another, and are simply variable populations...[with a] wide overlap in of their curves of variation.... Most of the truly crucial characteristics usually attributed to human race have nothing to do with their genotypes but are ethnic, cultural properties. Races have been said to be friendly, cruel, intelligent, stupid, reliable, devious, industrious, lazy, suspicious, prejudiced, emotional, inscrutable, and what not. Indeed, almost any attribute a person may have has been claimed to characterize one or another human race. I am unaware of any scientific confirmation of any of these claims.... That no two individuals are alike is as true of the human population as of all other sexually reproducing organisms. Each individual is a different combination of morphological, physiological, and psychological characteristics, and of the genetic factors that contribute to the shaping of these characteristics. There is no doubt as to the great plasticity of the human phenotype, particularly as far as behavioral characteristics are concerned, but genes also make a contribution.... Indeed, few human characteristics can be found in which there is not a great deal deal of variation (polymorphism) in every human population. It is precisely this diversity that forms the basis for a healthy society. It permits a division of labor, but it also requires a social system that makes it possible for each person to find the particular niche in society for which he or she is best suited.... Neglect of human biological diversity in the name of equality can only do harm; it has been an impediment in education, in medicine, and in many other human endeavours. Great sensitivity and a high sense of justice are required to apply the principle of equality in the face of human biological diversity. As Haldane (1949) said so rightly, ‘It is generally admitted that liberty demands equality of opportunity. It is not equally realized that it also demands a variety of opportunities, and a tolerance of those who fail to conform to standards which may be culturally desirable, but are not essential for the functioning of society.”
(Mayr, pp.244-7)



John Henry Calvinist