Many people I have discussed Popper with seem confused by Popper tying together evolution and epistemology in his book Objective Knowledge and other places. Evolution, they say, is all about biology and epistemology is about what people think. I’m going to try to clear up this confusion.
Let’s suppose we do just want to understand what people think. How do you learn to understand anything complicated like quantum physics, or drawing, or philosophy? Well, it involves reading, talking to people, making notes, drawing, or painting, or making other things and so on. So you can’t understand what people think without looking at the books they read, the conversations they have and the things they make.
And what do we want to understand about what people think, anyway? When we notice a person’s knowledge, it’s because he has done something right that other people would get wrong. Somebody who is good at programming, writes good programs; other people don’t. Somebody who is good at physics, writes good stuff about physics; other people don’t. The difference between competent and incompetent people needs to be explained and what explains it is that the competent people have knowledge – that is, useful or explanatory information.
Objects can be competent too in the sense of being able to do things that other objects can’t do. Planes can fly, but most other objects of similar mass can’t fly. Books, web pages and so on can convey explanations more easily than other things, like bananas and planes. This competence needs to be explained too and it is explained by the fact that they instantiate knowledge. Planes instantiate knowledge about how to fly; books and web pages instantiate knowledge about how to convey explanations.
Organisms can be competent in that sense, too. Photosynthesizing organisms can use sunlight to produce useful work and most objects can’t do this. Monkeys can climb trees, cheetahs can run fast, sloths can extract energy from tough leaves, some trees can grow very tall and so on. This competence has to be explained too and it is explained by the fact that they instantiate knowledge about the world.
How do we explain biological knowledge? Genes instantiate information about how to make cells specialise and arrange them in the right way. Mutations produce variations in those genes, and different variations spread themselves better in different environments. So biological knowledge is produced by variation and selection. Human knowledge is produced by making variations on our current knowledge and then selecting those that solve problems best. So human knowledge and biological knowledge are both produced by processes that involve variation and selection. Hence the link between biology and knowledge and evolution and epistemology.
