Aristotle's Biology; Philosophy or Science?  

                                                                                   Copyright©James Jope

Aristotle has always been recognized as a major philosopher, but his biology has received less attention from philosophers than the subjects which are still regarded as philosophy today, such as metaphysics. Modern science, on the other hand, developed largely in opposition to Aristoteleans, and most scientists have little interest in the Stagyrite’s superceded achievement. Those who do (e.g.,Carl Friedrich von Weizsäcker) sometimes find his thought surprisingly compatible with their own.

The two books on Aristotle’s biological work reviewed here open intriguing new perspectives. One exhibits recent work in the budding discipline of the philosophy of biology, and the other is a balanced appreciation of Aristotle as a scientist by an informed biologist.

While the philosophers derive from Aristotle interesting solutions to modern issues in the philosophy of biology, the biologist shows a more empathetic understanding of the Stagirite’s life and method.

Heinemann, Gottfried and Rainer Timme (edd.). Aristoteles und die heutige Biologie: vergleichende Studien. Lebenswissenschaften im Dialog, 17. Freiburg; München: Verlag Karl Alber, 2017. 352 p. € 39.00 (pb). ISBN 9783495486924.

Leroi, Armand Marie. The Lagoon: How Aristotle Invented Science. London: Bloomsbury, hb 2014; pb 2015, 502 p., £9.99, ISBN 978-1-4088-3622-4 Aristoteles und die heutige Biologie is a collection of papers originally presented at a conference at Kassel University in 2009. The contents are shown at the end of this review.

Georg Toepfer opens his essay with these words: “Die Teleologie des Organischen bei Aristoteles soll in diesem Beitrag nicht primaer aus der Perspektive der Aristoteles-Forschung untersucht werden, sondern aus der Perspektive der Philosophie der Biologie und deren Diskussionsstand der letzten Jahrzehnte.” The same could be said of most of the papers in Heinemann and Timme. The book could have been titled “Aristotle and Biophilosophy”; there is much on issues like teleology, ontogeny and Aristotle’s hylomorphic theory of body and soul as ontologically inseparable aspects of a single entity (matter and form, respectively), but only a secondary interest in the Stagirite’s extensive empirical observations and analyses. Contributors occasionally disagree, launching philosophical discussions from their Aristotelian point of departure. The essays are arranged in five parts and summarized on p. 19-22. Biophilosophy has become well established in recent decades, and a focus on Aristotle is welcome. Readers who may have expected a study of Aristotle more specifically qua biologist will like Armand Marie Leroi’s The Lagoon: How Aristotle Invented Science. Leroi is a professor of evolutionary developmental biology who, taking as a role model D’Arcy Thompson, another biology professor who could not restrain his interest in classical studies, undertook to master adequate classical scholarship to freshly interpret Aristotle showing how a scientist can offer new insights concerning the ancient philosopher.

Turning first to Heinemann and Timme, Gottfried Heinemann’s own contribution is a thorough study of problematic Aristotelian texts cited in an ongoing dispute with David Sedley and others. Sedley has postulated that ‘nature’ (physis) must mean a global figure like the modern ‘Nature’ in passages where, for example, Aristotle says that plants and animals are made by ‘Nature’ for man’s benefit. Heinemann insists that Aristotle’s physis is always only the nature or ‘form’ of a particular species. This controversy cannot be resolved here. If we accept the orthodox assumption that Aristotle gradually distanced himself from Plato, Heinemann’s view fits more smoothly with Aristotle’s mature philosophy, in which there is neither creation nor a providential agent. A global Nature is rather reminiscent of Plato’s creating demiurge. Yet I believe that Sedley’s interpretation of some texts is more straightforward, while Heinemann’s seems forced.

It is regrettable that Heinemann chose to quote these texts only in translation. Readers following a controversy over verbal usage need to see the Greek. Jochen Althoff, to his credit, is the only contributor who reproduces extensive quotations in Greek. When his opponent Georg Toepfer discusses a familiar “zentrale Textstelle” from Aristotle on p. 294, he assesses conflicting translations without even providing a reference to the Greek text.

Althoff and Toepfer dispute to what extent Aristotle can be credited as the source of the concept of an ‘organism’ even though he did not use the word. They agree that some features of the concept, such as describing the living entity and its organs in terms of functional teleology (the eye is to see, etc.), are Aristotelian. But Toepfer disputes Althoff’s ascription of the origin of the concept to Aristotle. A critical feature of the modern concept of an organism is the interdependency of its organs. Althoff suggests that the processing of food by heat into blood and then sperm or menstrual blood as it passes through the body—i.e., the basic animal functions of nutrition and reproduction according to Aristotle—is an interaction of the organs comparable to metabolism. Toepfer argues that Aristotle’s use of the soul as the organizing principle in an animal, instead of just the interaction of the organs themselves, kept him from realizing the importance of their interaction, which Toepfer believes was first acknowledged with the concept of ‘sympathy’ in Galen and the Stoics. But arguably, the Stoics too employed an organizing principle, viz., the ‘fire’ which energizes organisms and the universe.

The key to such disputes is, of course, how generous one wishes to be towards Aristotle, how closely his theories must approximate their modern comparanda. Niko Strobach shows how reducing two compared theories to exact propositions on which both would agree formulated in symbolic logic can reveal unexpected similarities and differences. This method might be useful in settling disputes. However, for Strobach’s own example regarding the constancy of species he has to dwell disproportionately on exceptional cases such as mules to obtain significant results. If we try to reduce, e.g., Althoff’s metabolic comparison to such a statement, it would be trivial: “Living things ingest and assimilate materials from outside.” Thus, crude comparisons which may nevertheless have heuristic or historical value could be rejected.

The essays by Kirsten Schmidt, Kristian Koechy, and Martin Norwig all discuss important issues of modern biology and indicate solutions proposed by other philosophers which they believe to be compatible with Aristotle. Schmidt and Koechy review historical theories of ontogeny (embryological development) after Aristotle, leading up to the deciphering of the genetic code, and then show that more recent biological evidence following that discovery does not support the common view that genes exclusively dictate the complete development of an organism. Popularly promoted by Richard Dawkins (The Selfish Gene 1978), this meme is typified in the current cliché that any interest or achievement of an individual “is in her DNA”. This oversimplified belief still largely dominates popular opinion, so that these papers are timely and constructive. However, the respective alternatives proposed by the authors are diametrically opposed. According to the meme, the genome comprises a program which solely determines and controls the development of an organism, a role comparable to that of Aristotle’s ‘form’ or ‘soul’. However, further research has revealed other, ‘epigenetic’ causal factors. For example, activation of the genes to develop particular body parts can be determined by their position in a foetus through chemical gradients. Such positional mechanisms were explored in depth by Gerald M. Edelman (1988), who coined for them the term ‘topobiology’. For a proper understanding of the interaction between genes and other embryological factors, Schmidt advocates Susan Oyama’s ‘Developmental Systems Theory’ (The Ontogeny of Information 1985), which follows the ontogenetic process without postulating any one guiding agent, be it ‘form’ or genome. For Schmidt, ontogenetic development is contingent on environmental influences to such an extent that it has no regular final outcome. That allows for the long-term evolutionary variation of species but does not explain their short-term constancy. As for Aristotle, Schmidt does not adequately discriminate between his hylomorphic soul, which is inseparable from the body, and the Platonic-Christian version, a vitalist “Entitaet… die zum Entwicklungsprozess in einer Beziehung von Schoepfer und Schoepfung steht” (p. 79, my emphasis).

According to Koechy, Aristotle’s view tracing the ‘form’ of the species to the father (“anthropos anthropon genna”) prevailed until twentieth-century biologists located it either in the genes (molecular biology) or in populations (evolutionary biology). However, some (Ernst Mayr and Stephen J. Gould are best known) have argued that the focus should return to individuals, as they both control epigenetic factors and supply the mutations on which natural selection works. Koechy refers to Denis Walsh (Evolutionary Essentialism 2006) to restore an essentialist view more like Aristotle’s by rewording the principles of natural selection: For example, instead of describing the environment as selecting mutations, we should say that the mutations must occur in a sufficient number of individuals to become established.

Norwig discusses the issue of physicalist reductionism, i.e., the belief that biological phenomena can be explained by the underlying purely physical properties, so that biology should eventually no longer be a separate science from physics. He surveys variants of physicalism from the extreme version proposed by logical positivists early in the last century to moderate recent models which allow some scope to study such concepts as evolution or biodiversity, and finally advocates J. Kim’s ‘supervenience’, a special type of covariance between two sets of properties, physical and biological, such that the latter are dependent on the former but without any assumption of causality. Norwig argues that this concept accommodates such recent advances as the correlation of mental processes with physical events in the brain in cognitive science. He compares the supervenient correlation of cephalic and mental processes with Aristotle’s hylomorphism. This comparison is workable, but only insofar as the soul is inseparable from the body. However, led by his own choice of cognitive science as an example, Norwig applies the theory to mind and thought without any mention of Aristotle’s belief in an ‘agent intellect’ which is separable from the body—a remnant of Platonism, perhaps, but if one must discuss cognitive activities, it should be considered.

What this book offers is a philosophical discussion positioning Aristotle on issues in the philosophy of biology. The issues are current and the overall understanding of Aristotle is satisfactory, but the emphasis is on modern biophilosophical theory. It may be symptomatic in this regard that while these authors turn to (modern) third-party theorists to bridge Aristotle with modern thinking, Leroi argues that Aristotle himself is compatible with modern findings if correctly interpreted.

As mentioned above, Leroi, who teaches developmental biology at the university of London, set out to interpret Aristotle from a biologist’s point of view. From his own experience he can tell when Aristotle actually did perform a dissection, how he made mistakes, and when he only read other sources; Aristotle did not dissect a dolphin, but he definitely did dissect cuttlefish. Leroi also observes, for example, that Aristotle’s account of animal life cycles satisfies the modern finding that the reproductive fertility of a species is inversely proportional to its infant mortality rate and longevity, a relationship which scholars may fail to appreciate in Aristotle. As scholarly sources he lists David Balme, Allan Gotthelf, Wolfgang Kullmann, James Lennox, Goffrey Lloyd, and Pierre Pellegrin, but his reading extends beyond these in ancient as well as modern sources, including not only philosophers like Empedocles, but miscellaneous authors such as Athenaeus.

Whereas contributors to Heinemann and Timme compare historical background material mainly after Aristotle, Leroi’s historical comparisons relate Aristotle back to Empedocles, Democritus and the Hippocratics, as well as forwards to Cuvier, Harvey etc.

His account of Aristotle’s four causes exemplifies the biological orientation which characterizes the entire book: “The efficient (or moving) cause is an account of the mechanics and movement of change. It is now the domain of developmental biology and neurophysiology… The formal cause is an account of the information transmitted that any creature received from its parents, and that is responsible for the features that it shares with other members of its species—that is, the subject matter of genetics. The final cause is teleology, the analysis of the parts of animals in terms of their functions. It is now the part of evolutionary biology that studies adaptation.” (p. 92). However, Leroi also targets a wider audience. He personally retraced Aristotle’s expedition to a lagoon at Pyrrha where they both collected specimens, and he enlivens his account with descriptions of local flora, fauna and topology, with sometimes irrelevant illustrations, and with amusing, albeit patronizing reports of encounters with Greek fishermen.

Some of these efforts to make the book attractive for any educated reader may deter scholars. I have not reproduced the table of contents, because it is not a useful guide: It mysteriously lists a chapter on “The Soul of the Cuttlefish”, which turns out to discuss de Anima. “Instruments” is about the Organon. “Foam” is de generatione Animalium, and “Figs, Honey and Fish” concerns life cycles. The reason for this is that it is precisely with regard to these organisms that Leroi analyses Aristotle’s doctrines. The cuttlefish chapter, for example, gives a full account of the nutritive soul, in which Leroi too compares its action to metabolism. However, scholars will find little guidance to specific topics apart from the index. Documentation is provided in endnotes and appendices, but when Aristotle’s text is quoted the reader will not always find an exact reference. Footnotes serve, instead, to enlighten the classical reader on relevant aspects of science, or the scientist on additional ancient material.

On page after page, Leroi illustrates zoologically relevant aspects of Aristotle’s thought in concrete examples from the biological treatises. He shows how Aristotle used the interaction of functional teleology (the eye is to see) and ‘conditional necessity’ (if it is to see, it must be vitreous) to approximate in his static species a modern understanding of adaptation. Leroi even has a plausible argument to relate Aristotle’s scientific method to biology: “For all its limitations, Aristotle’s theory of demonstration is a genuine scientific method. It is part of ours. Scientists may quarrel about methodology but… They understand the domain of science… They understand… the reciprocal role of theory and evidence and the distinction between hypothesis and fact. They understand that science begins with induction to give generalizations from observations and then deduction to give firm causal claims from generalizations… That they understand all this is because Aristotle told them it was so.” (p. 131-2).

But beyond this, he grapples with overall issues like the unity and chronology of Aristotle’s thought. He is sometimes less impressive here, as when he explains the cosmos as an organism or compares ‘natural slaves’ to modern factory workers, but it does enable this book to serve as a complete introduction to Aristotle. Leroi’s major criticisms of Aristotle—and they are undoubtedly correct--are that his rejection of atomism and his embrace of ‘homoiomerous’ basic materials led to errors throughout his work; and that methodically looking for the truth in received wisdom made him too conservative. Regarding spontaneous generation, for example, Leroi argues that it was contrary to Aristotle’s own theories, and then proceeds to show how, step by step, Leeuwenhoek and others refuted it—with a nod to Homer.

Leroi’s exploration of Aristotle and his lagoon is a captivating interdisciplinary disquisition, and both books offer a wealth of material for reception studies.