Scientists study how and why things happen, or why they are as they are. They can use this knowledge in many different ways: to predict what will happen in certain circumstances, to understand why bodies and machines sometimes go wrong and to try to prevent this or put it right, and to develop inventions that will make a difference to the world. The first scientist was probably a very early human or even human ancestor, who noticed something about the world, began to think about why this might be so and tried to test these ideas.
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.