AUTHOR: ARISTOTLE
DATE: C. 350 BC
Aristotle was one of the three leading intellectual giants of Ancient Greek philosophy. His works are the product of an extraordinary intellect that ranged across myriad subjects – among them politics, ethics, metaphysics, logic, psychology, physics, zoology, rhetoric and aesthetics. As such, he has had a profound influence on virtually every major intellectual movement, certainly in the West, that has come since. To choose his magnum opus is, perhaps, a fool’s errand, since any number of his known works (and there are a great many that have been lost) might qualify. Nonetheless, his History of Animals stands as a landmark enterprise, considered by many as the first major scientific study of life on earth and the foundation document for the discipline of empirical biology.
Aristotle was born in Stagira, Chalcidice (not far from Thessaloniki in modern-day Greece) in 384 BC. He perhaps developed an early interest in matters of the living world as a result of his father being a doctor in the court of the Macedonian royal family. Aristotle enjoyed an education open only to the privileged and, when he was seventeen, joined Plato’s Academy in Athens – where he stayed for twenty years, first as a student and then a teacher. He seemed all set to replace the ageing Plato as head of the Academy, but at the last the position went to Plato’s nephew instead. Moreover, the political temperature at the time was rising in Athens, and Aristotle felt a growing anti-Macedonian sentiment. So, around 348 BC, he chose to leave the city and made for Ionia (a region of Anatolia’s Aegean shore in what is now Turkey) and then to the island of Lesbos.
Here his passion for biology and the natural sciences could be fully explored. Where Plato had believed that knowledge and wisdom stems from the application of reason, Aristotle was certain that the study of nature would bring its own enlightenment. He began a systematic study of the indigenous flora and fauna, both on land and in the sea, for instance seeking out every example he could find of a particular species in order to draw general conclusions about the species as a whole. With his reliance on evidence-gathering and repeated observation to arrive at broader inferences, he prefigured the modern scientific method by the best part of two thousand years.
Aristotle wrote up his research in what became the History of Animals – the ancient world’s greatest work of natural history, zoology and marine biology. Along with two later additional treatises – On the Parts of Animals and On the Generation of Animals – it is the most well known of his biological works, which account for about a quarter of his surviving writings. His broad methodology was to explore existing facts (in Greek, hoti) in a bid to explain their causes (dioti). In practice, this meant looking at animal anatomy and physiology, investigating the differences between body parts and other characteristics, and exploring modes of behaviour, while also considering what was the result of design and what had occurred through chance.
To this end, Aristotle practised several techniques that propelled natural history forward in exponential ways. For example, he created an extensive system of hierarchical classification that provided the basis of the taxonomy that we use in the modern world. Beginning with living and non-living categories, he then sub-divided the types of all living things into, for example, plants and animals, and the plants into herbs, trees and shrubs, and animals as dwellers of the land, air or water, and so on. Groups all have shared characteristics, so that to be categorized as a bird, for instance, a subject must be living and have wings, feathers and a beak. But Aristotle did not solely rely on physical characteristics for classification. Instead, he looked at four ‘causes’ to explain existence: what something is made of; the shape or form it takes; how it is created; and what its purpose (or telos) is.
GREAT TIMES
Following his time on Lesbos, Aristotle was invited to Macedonia by King Philip II. Aristotle was charged with the education of Philip’s son Alexander, who would go on to become known as Alexander the Great, one of the most effective empire-builders in history. While at the Macedonian court, Aristotle also contributed to the education of two other kings-to-be: Cassander (who would rule Macedonia) and Ptolemy (a future Egyptian pharaoh). Aristotle would eventually fall out with Alexander, however, and it has even been suggested (although with scant supporting evidence) that he might have been involved in the ruler’s death when he was aged only in his early thirties.
He also practised dissection, still in its infancy, as a means of better understanding the anatomy of the animals under his study, although his work detailing these examinations has been lost to us. Sometimes relying on others’ accounts of creatures that they had observed (for instance, mariners and bee-keepers), Aristotle’s conclusions were not always correct. But some of his analysis was extraordinary. His account, for example, of the colour-changing phenomenon of an octopus and his description of male river catfish guarding eggs in lieu of the mother was considered highly improbable until empirically proven in the modern age. The History of Animals vastly increased humanity’s bank of knowledge about the physiology and nature of hundreds of different species.
More importantly, it laid out the basics of a system that biologists have worked within ever since – an evidence-based scientific approach that prizes observable phenomena over hypothetical theories. The living world became an environment not defined by superstition and folklore, but by rational investigation and analysis. After Aristotle, natural historians could not merely talk in terms of what they thought was going on, but needed instead to show it to be so.
Such was the impact of his work that it was not substantially superseded until the sixteenth century, when such lauded names from the world of zoology and biology as Conrad Gessner, Volcher Coiter, Guillaume Rondelet and Ulisse Aldrovandi were busy researching in their various corners of Europe, each of them familiar with and building upon Aristotle’s efforts. William Harvey, best known for describing the circulatory system, was another who drew heavily on Aristotle’s findings in his work in the field of embryology. Sir Richard Owen, the celebrated nineteenth-century English naturalist, was fulsome in his praise of Aristotle’s achievements: ‘Zoological Science sprang from his labours, we may almost say, like Minerva from the Head of Jove, in a state of noble and splendid maturity.’