“All men desire to know. But not all forms of knowledge are equal. The best is the pure and disinterested search for the causes of things.” Paraphrased from Aristotle’s Metaphysics - Book One.
“In this subject, as in others, the best method of investigation is to study things in the process of development from the beginning.” Aristotle’s Politics - Book One.
Although the origins of science has roots in the ancient Greek city-state of Miletus, and some historians have referred to Thales (c.624-546 BCE) as the “father of science”, Thales was no scientist. Nor were those who followed in his footsteps. This is because none of the early Greek (“pre-Socratic") philosophers, from Thales to Democritus, explained in detail how their theories accounted for the appearance of things. For example, Thales is said to have argued that everything is made of a single universal substance: water. But he never explained why the things we observe rarely seem to be made only of water - e.g., the sun. For a theory to be scientific, it must have at least some explanatory power. Nor did the speculations of these early philosophers lead to new information about nature. Most notably, these early philosophers made no attempt to verify or even justify their speculations. It clearly did not occur to them to do so.
Nevertheless, the pre-Socratics laid down the foundations of Western philosophy, and thus, science. Reason had become more important to Greek thinkers than supernatural explanation. Leucippus argued that “no thing happens in vain, but everything for a reason and by necessity”. His successor Democritus reasoned that reality comprises only two things: tiny indivisible particles called "atoms" and void. Pre-scientific—but rational—speculations were beginning to flourish.
Good ideas were not unique to ancient Greece. Great thinkers can be found across the ancient world, especially in ancient India and China (India particularly has a very long tradition of valuing knowledge). But the scientific tradition has at least one root in ancient Greece. Why? In the 4th century BCE, a well-connetced man of 17 or 18 years of age [the son of the personal physician to King Amyntas III of Macedon] left his guardian’s care in Stageira in northern Greece and arrived in Athens, where he was welcomed into Plato's famous Academy. That young man was Aristotle (384-322 BCE) and he was about to change the world.
More about Aristotle in a bit. First, some context. Plato is widely regarded as the super star of Western philosophy. He became a philosopher through Socrates. Socrates was despised by many of his fellow Athenians for questioning everyone and everything. And in science, you have to question everything. Truth-seeking requires a curious, open, inquiring mind that is not afraid to challenge dogma and test assumptions; this is at the heart of the scientific tradition. Some time after the death of Socrates in 399 BCE, Plato set up a community of philosophers to engage in research, discussion, and learning. They met outside the city walls of Athens in Hekademia (which later became known as the Academy), a large plot of land adorned with olive trees.
Plato’s Academy was one of history’s great centres of learning. The young Aristotle must have been exposed to a wide range of philosophical ideas. He would have learned to question everything, to reason about things. It was the best education anyone could have had in Europe at that time. For example, he would have been taught by the mathematician and astronomer Eudoxus, who introduced a new rigorous style to mathematics, in which theorems are deduced from clearly stated axioms. What effect might this have had on Aristotle and the origins of science? Aristotle went on to develop the field of formal logic (e.g., "if all men are mortal, and Socrates is a man, then Socrates is mortal”). I wonder whether his huge contribution to logic was inspired by what he had learned from the mathematicians in the Academy. Aristotle’s conception of logic remained the dominant form of Western logic until advances in mathematical logic over two millennia (twenty-two centuries) later! He would also have learnt about the physician Hippocrates, if he had not already. After Hippocrates, physicians no longer asked “Who [what supernatural entitiy] caused this sickness?” but rather, “By what [natural] process does this sickness occur?” Although ancient Greek medicine was nothing to boast about, observation now seemed important to them, as it is in science today.
After Plato’s death, Aristotle moved to the coastal town of Assos in Asia Minor (which was ruled by his friend and a former slave Hermias) and then to the nearby island of Lesbos, where he made detailed observations of plants, marine life, and life in an enormous lagoon. And this highlights the difference between the great philosopher Plato and the proto-scientist Aristotle. Plato believed in the reality of abstract things - e.g., he argued that whereas the ideal form of an olive tree is real, individual (imperfect) olive trees are illusory. He also argued that knowledge was innate. For Aristotle, however, individual (imperfect) olive trees are perfectly real, and knowlegde is gained only with experience. To learn about nature, you must observe it. And he observed it. And more importantly, he learned from his observations. From the delay between seeing lightning and hearing thunder, or seeing oars on a distant ship and the sound they make striking the water, he was able to conclude that sound travels at a finite speed. He also used observation to infer that the earth is spherical and to understand that rainbows are caused by light that has been reflected by small particles of water suspended in the air. Observation is a key component of science (along with curiosity and a willingness to detail and verify theories). We cannot understand the world by thinking about it from the comfort of our armchair (as Plato believed). We must go out into the world and make observations. “More dependence must be placed on facts than on reasonings, which must agree with facts,” wrote Aristotle.
And in Lesbos, Aristotle observed. He systematically gathered data. He dissected organisms. He was the first person to cut open a window in the egg shell of a chick, peer inside, and describe what he saw: an embryo, the beginning of a living thing.
Like modern biologists, Aristotle saw no fundamental difference between humans and (non-human) animals. All living creatures have a soul ψῡχή (‘psyche'), he said. But Aristotle’s soul was not the same as Plato’s or the Judeo-Christian soul. It was not something supernatural or mystical. For Aristotle, the soul is the principle that keeps the animal alive, and when the soul falls apart, the animal dies. For Aristotle (as it was for many Buddhist thinkers at that time in India), the soul was merely the interrelation of parts from which life arises.
Furthermore, and like modern biologists, Aristotle also argued that the form of an animal does not depend on what it is made of (its elements). For Aristotle, elements are like letters (A and B). You can combine them in various ways (e.g., AB or BA) and it is the arrangement or order of these elements that gives the animal its specific form, not the elements themselves. A bit like DNA.
Aristotle did not just collect data, he organised data too. He noticed patterns; how some creatures ressemble each other. He separated dolphins and whales from fish, because they breathe air and suckle their young. This research activity bears a striking resemblance to modern science.
At the request of King Philip II, Aristotle returned to Macedon to head the royal academy and tutor Philip’s son Alexander (who became Alexander the Great). He also tutored two other future kings there: Ptolemy and Cassander. By 335 BCE, Aristotle returned to Athens and established a new centre of learning in one of the buildings of the Lyceum, a large public space beyond Athens' east wall. This centre of learning may well have been the world’s first university (though it did not award degrees) and included activities that did not occur in Plato’s Academy, such as cooperative research, student (as well as scholarly) research, public lectures, and book-collecting. Aristotle’s library may have been the first library in Europe and the model of the Library of Alexandria.
So what was Aristotle’s legacy? Although Plato is considered by many to be the greatest philosopher in history, Aristotle was arguably the most influential. For nearly 2000 years, when men inquired about the natural world, they first asked: “What did Aristotle think?” And such was his mind and scope of investigations that invariably he had an answer. Medieval Muslim scholars called him "The First Teacher"; medieval Christians called him "The Philosopher”. At the heart of every medieval university curriculum was Aristotle. And with his emphasis on detailed observation and formal logic, his reputation was well deserved; he was arguably the world’s first biologist.
Why, then, do scientists (including biologists) not revere Aristotle to the same extent as they do Galileo, Newton, Darwin, and Einstein? Science is about observation. It is about finding patterns among observations and using them to theorise. Aristotle did this more than anyone else. But there is more to science than that. There is give and take between theory and data. Scientists develop theories based on evidence, but they also test (and continuously refine) their theories with data.
Take for example Aristotle’s theory of abiogenesis (spontaneous generation). Aristotle observed that under certain conditions, some creatures (e.g., maggots, eels, clams, oysters, barnacles) emerge from nonliving things - or so he thought. For example, if you leave a dead animal out in the sun, it will soon be crawling with maggots, which seem to appear as if out of nowhere. In fact, Aristotle would have observed that eels seem to emerge from the mud at the bottom of the seabed and not from eggs; and when he dissected them, he would have observed that they have no testes. (What Aristotle did not know is that eels often hide in the seabed and only develop testes when they travel vast distances to their breeding grounds far from Lesbos.) One cannot fault Aristotle for his observations, nor for his logic or theory. However, had he tested his theory by devising a simple experiment, he would have realised that his theory needed revising. This is what science is really about!
One such experiment took place in the 1660s (and was published in 1668). Francesco Redi placed meat in three jars. One jar was left open. One was tightly sealed. One was covered with porous gauze which allowed air to enter but not flies. The rotting meat in all three jars attracted flies. But of course, although maggots emerged from the meat in the open jar, they did not appear in the meat in the other two jars. Also, when dead flies or maggots were put in sealed jars with meat, no maggots appeared; but when living flies were put in sealed jars with meat, maggots appeared. Redi concluded that maggots do not arise spontaneously from rotting meat but from flies. A simple experiment (which was much improved upon by Louis Pasteur in 1859) demonstrated the problem with Aristotle’s method of inquiry and the power of the scientific method.
Historical sidenote: The Romans destroyed Plato’s Academy in 86 BCE, though the Academy lasted in one form or another until 529 CE. This makes it one of the oldest and longest enduring centres of learning in the history of the world. However, there may have been older centres of learning in ancient India. For example, there is some evidence of a centre of learning several centuries BCE in Taxila (Takshashila), an ancient city in Gandhara (now Pakistan) at the intersection of several important trade routes. It was not a university like later Nalanda (~500-1200 CE) in eastern India, though. Teaching at Taxila would have been more one-on-one, and there would have been no lecture rooms, etc., just monasteries. But it (and other cities in ancient India) seem to have attracted teachers and students from across India (and even some from China) for the sole purpose of understanding the world and ourselves within it.
