Descartes' Denial

I have written before about how Aristotle's teachings in philosophy set a supreme standard that still holds today—2500 years later. His reputation is so firm and strong that he is often referred to as simply “The Philosopher.” His teachings on science (called “natural philosophy” in his time), however, were subsequently shown to be mostly wrong. Unfortunately, his status was so towering that his errors prevailed for two millennia. The fact that the Catholic Church's teachings aligned with Aristotle's ideas helped to extend his theories over that long period of time.

Rene Descartes, in the 17^th century, began to speak out against Aristotle's scientific opinions. He was joined by the Irish scientist Robert Boyle, as well as several others. Both of them especially rebelled against the complex (and confusing) concept of “form,” which was championed by both Aristotle and Plato. Form, they believed, is the essential nature of something—a very abstract idea that says little about its particular qualities, and says nothing about what caused that something’s form.

Descartes and Boyle argued that the ancient concept of form is too vague and offers little help for allowing one to understand the important, causal physical properties of something, as well as how it behaves. They put forth instead what they called a corpuscular view of matter, proposing that all matter is constituted of tiny particles called corpuscles—a couple of centuries before the existence of atoms was proven.

They maintained that corpuscles move, bounce against, and connect to each other, and that their behavior is governed by the laws of motion—laws which had been expressed a few years earlier by Galileo Galilei. The Church tried one last shot at promoting Aristotle’s notion of forms, when a Jesuit, Francisco Sucrez, proposed that every object has a soul. Just as the human soul guides people from the inside, the soul of a tree guides its qualities from within and causes its form. It was a supernatural, not a scientific, explanation, however.

Descartes rejected this idea as even worse than Aristotle's teaching, because he was sure that inanimate objects could not have a soul. His—and Boyle's—idea was that the corpuscular theory provided a simple, mechanical world view. The activity of corpuscles drove the behavior of the parts of an object; it behaved like a machine. In fact, Descartes said that the body of living creatures is also like a machine, and does not require a soul.

Descartes soon displaced Aristotle, regarding the nature of matter. His and Boyle's ideas played a huge role in the scientific advances that occurred during the Enlightenment (late 17^th, into 18^th centuries). Nobody is perfect, however, and Descartes later expanded upon his views; saying that animals are machine-like and possess no soul, as humans do. He maintained that animals—being like machines—have no feelings, and do not therefore experience pain. It was another couple of hundred years before this concept was debunked—a period of time when physical harm to animals was deemed acceptable. As a result, we are finally beginning to treat animals with appropriate respect... well, except those we raise for meat.