Theories of Origins Before Darwin
What were the theories of origins before Darwin? What was there before Darwin? What did people think about the origin of life and the different species on Earty? One thing characterizes people, as Descartes would say, they think. As thinking creatures, we have always wondered about how the universe and things in it originated. We are particularly interested in our own origin.
The first chapter of Genesis contains the Christian creation account. It tells of God creating the heaven and the Earth, plants and animals, and then man in God’s image. All in six days. The Bible doesn’t state when this creation occurred, but most early Christians probably assumed that this did not occur too long ago. In the 1600’s, the Anglican bishop James Ussher fixed the date of creation at 4004 B.C.E. This is the established biblical view that continues to the present.
The Early Scientific Accounts of Origins
Over the past 2000 years, this creationist account did not exist alone within the western tradition. Religious accounts of origins, at least for the past 2000 years, have competed with scientific accounts of origins. Science began with the Greeks, about 600 B.C.E. At this time we find the firsts scientific explanations for natural phenomena.
Although many Greeks retained religious theories about nature founded on revelation or mythical stories, some philosophers proposed materialistic explanations founded on reason. What do I mean by materialistic? This means that they explained natural phenomena without recourse to God or the supernatural. These philosophers said that natural phenomena can be explained as the result of physical matter moving in accord with natural law, with God, at most, as the remote creator of the primordial matter and the laws of motion. We find this sort of account in Plato, for whom God created the primordial matter and its laws, and then left it operate.
Biological origins posed a particular puzzle for Greeks who tried to devise purely materialistic explanations for natural phenomena. Biological organisms, people specially, seemed much more intricate and intelligently designed than just rocks or mountains. They seemed created, and creation implies a creator.
So, to explain the origin of biological organisms, early natural philosophers, like Anaximander and the so-called atomists, proposed crude theories of evolution. They are not very detailed, but they had the idea that there was some sort of spontaneous generation of life and somehow species could evolve over time. They weren’t worked out very well.
Aristotle critiqued these ideas. Aristotle himself was an atheist, and first and foremost, a biologist. He was a very avid observer of life, particularly of fishes. Based on his close study of animals, Aristotle defined a species as a breeding group. A group of particular animals or plants that can breed, and produce offspring that eventually could reproduce. He concluded that species were fixed.
Rejecting both creation and evolution, Aristotle simply saw the species as eternal. They always existed. Later Christian philosophers tried to integrate Genesis with Aristotle. They typically viewed each species as created by God in the beginning, but then, using Aristotelian authority, asserted that these species remained fixed for all time in a perfect (albeit fallen) creation.
This was the dominant view for a millennium in the West. It began to break down, though, when religious authority began to break down.
Deist and Atheist Accounts
The breakdown of religious authority finally occurred during the Enlightenment, in the 1700’s. Notions of evolution began creeping back in. This happened particularly in France, where natural philosophers again struggled to devise purely materialistic explanations for life. Seeking to push God back to the beginning, deists proposed a variety of ideas. They proposed that the solar system was created not by God, but rather a comet once hit the sun and knocked off a bunch of matter, which separated, each piece becoming a planet.
They also proposed ideas for the origin of species. They said that the tremendous array of species evolved from a few common ancestral types. Some of the French natural philosophers were even more atheistical. Denis Diderot, for example, a committed materialist, proposed that all living forms developed by random chance mutations from spontaneously generated organisms.
Probably the most influential natural philosopher from this period was the astronomer Pierre Laplace, who proposed a purely materialistic explanation for the origin of the solar system. He said that the solar system was once a big rotating gas nebula, and as it rotated, centrifugal and centripetal forces would pull in matter to the center, which became the sun, but as it pulled in, it left little blobs of material that collapsed into the different planets. This was called the nebular hypothesis.
When Laplace described his theory to Napoleon, he was asked “how does God fit into it?”, Laplace famously responded “I have no need for God in my hypothesis”.
All the ideas that we’ve gone over were highly speculative and were driven more from philosophy than empirical scientific research. There were a few discoveries at the time, though, that reinforced these ideas.
For example, Abraham Trembley detected that polyps, which are very simple sea creatures, could regenerate. By cutting them into pieces they regenerated the whole. They could be flipped inside out and still operate. People saw this as “almost spontaneous generation”. Philosophers took this as scientific evidence for their speculations.
Overall, however, the empirical research during this period cut the other way. Even if these ideas were speculated about, when people actually did the experimental and observational work in nature, most of them opposed the evolutionary ideas. The generation after the Enlightenment reacted against the speculative nature of evolutionary ideas. They returned to creationism, although not the creationism of the Bible, but a creationism based on scientific evidence. I will discuss this in my next post, when we see how Georges Cuvier founded modern biology.
Post a Comment