Abstract
Popper suggests human thought and ideas exist in a world of their own, transcending our thought processes and the material world. Theories, and other human ideological creations such as values, institutions and works of art, develop independently of those who work on them, and have a causal effect on them. What Popper suggests in support of his Platonism does not show that our theories are autonomous in any non trivial way. Also the picture of an abstract world of ideas causally affecting our thought processes is fraught with difficulty.