Roberto Lo Presti applauds a brilliant reappraisal of Aristotle as the father of observational biology.
Aristotle is considered by many to be the first scientist, although the term postdates him by more than two millennia. In Greece in the fourth century BC, he pioneered the techniques of logic, observation, inquiry and demonstration. These would shape Western philosophical and scientific culture through the Middle Ages and the early modern era, and would influence some aspects of the natural sciences even up to the eighteenth century.
Armand Marie Leroi’s reappraisal of this colossus, The Lagoon, is one of the most inspired and inspiring I have read. It combines a serious, accessible overview of Aristotle’s methods, ideas, mistakes and influence with a contextualizing travelogue that also found expression in Leroi’s 2010 BBC television documentary Aristotle’s Lagoon. Leroi’s ambitious aim is to return Aristotle to the pantheon of biology’s greats, alongside Charles Darwin and Carl Linnaeus. He has achieved it.
Leroi, an evolutionary developmental biologist, visits the Greek island of Lesvos — where Aristotle made observations of natural phenomena and anatomical structures — and puts his own observations in dialogue with those of the philosopher. It was in the island’s lagoon of Kolpos Kalloni that Aristotle was struck by the anatomy of fish and molluscs, and started trying to account for the function of their parts. Leroi’s vivid descriptions of the elements that inspired Aristotle’s biological doctrines — places, colours, smells, marine landscapes and animals, and local lore — enjoin the reader to grasp them viscerally as well as intellectually.
Aristotle’s time on Lesvos was only a chapter in a life of discoveries, and Leroi covers those signal achievements with breadth and depth. He details the theoretical and methodological principles governing the functional anatomy of species from pigeons to tortoises, discussed by Aristotle in On the Parts of Animals, as well as the descriptive zoology expounded in his History of Animals. For instance, Leroi explores Aristotle’s theory of causation, based on the distinction between material, efficient, formal and final causes. He looks at the philosopher’s views on the directedness of natural phenomena and the role played by necessity and hazard. He sketches out the theory of four elements (fire, air, water and earth) as the prime constituents of natural bodies. And he looks at the theory of soul and its relationship to the body — through which Aristotle accounted for aspects of physiology and psychology, from nutrition to rational thinking.
Fascinating chapters are devoted to Aristotle’s gradualist conception of the natural world and living things — perhaps best expressed in the saying natura non facit saltum, or ‘nature does not make jumps’. Also covered is his theory of sexual generation and transmission of hereditary traits, which he expounded in the masterful On the Generation of Animals. Despite a number of mistaken assumptions (such as the lack of a female ‘seed’), this theory encompasses a huge number of valuable observations and insights that laid the foundations of modern embryology.
The Lagoon traces other ways in which Aristotelian thought has permeated Western science. Leroi charts its influence on Renaissance anatomists and physiologists. The English physician William Harvey’s discovery of blood circulation, for instance, was largely inspired by Aristotle’s biological ideas, especially the concept of the heart as the most important organ in the body, as well as by Aristotle’s empirical emphasis on investigation and demonstration. Leroi shows how masters of comparative anatomy including Georges Cuvier (1769–1832) took inspiration from Aristotle in describing and comparing the parts of animals in light of their function as well as of their shape. He compares Aristotle’s theories with the thinking of taxonomists such as Linnaeus, of Darwin on evolution, and of the twentieth-century fathers of systems theory and cybernetics such as Walter Cannon and Norbert Wiener.
Leroi is careful not to represent Aristotle as a precursor in crude terms, or to read him through inappropriate contemporary lenses. Instead, he highlights aspects of Aristotle’s doctrines that still ‘speak’ to contemporary scientists, and that have been illuminated by modern scientific understanding — for example, Aristotle’s emphasis on direct observation and dissection. The philosopher argued, Leroi explains, “that ‘knowing’ in the sense of ‘perceiving’ is the foundation of ‘knowing’ in the sense of ‘understanding’”.
As Leroi acknowledges, decades of scholarly effort by philosophers and historians such as Allan Gotthelf and James Lennox have gone into the reassessment of Aristotelian biology and its effect on the history of Western science. In this respect, the book broaches no new questions, and brings no new perspective to the heated debates among Aristotelian scholars.
But that is to miss its point. The Lagoon is a wonderful introduction to Aristotle’s biology, which specialists will also enjoy. Every page is a reminder of the great beauty that we can experience by seeing the world through Aristotelian eyes.