Evolutionary ideas

So, where did this idea of evolution come from? Well, there are always ideas. You can go back to Aristotle and find elements of evolutionary thought in Aristotle, but really, it's a 19th-century idea. And in order to see how it developed, let's go back to about 1790 or 1800, so at the end of the century of the Enlightenment. At that point, if you were to ask a well-educated person living in a Western culture how old the world is, they would say, Oh, thousands of years. And if you were to ask them, Well, where did all these species on the planet come from? They would say they were all created just the way they look now, and they've never changed. If you asked them, "Have there ever been any species that went extinct?" They would say, No. Everything that was created is still alive and can be found somewhere on the planet. So when Alexandre von Humboldt, who was certainly a creature of the Enlightenment, set out to explore South America, he thought that he might encounter some of those strange fossils that the French had been turning up in the Paris Basin on top of a tepuy in Venezuela. So he really thought that there was a lost world. Of course, Arthur Conan Doyle later wrote a novel about that. I mean, these guys thought, Hey, I'm going to Venezuela, or I'm going to the Congo, I might meet a brontosaurus. That was what they thought.