Of all the controversial positions I take, the most controversial may Jaynes' bicameralism -- that consciousness is a relatively recent development

For a brief introduction to bicameralism, I suggest reading the this article on the topic.

I do not know if bicameralism is true, but if it were, it would be a radical transformation of most of our understanding of the development of consciousness; if false, then it is still a wonderfully creative conjecture.

Edit: Daniel Dennett, a man that I have the sneaking suspicion often has little to say in a great deal of space (in other words, more often than not he's not my cup of tea), has a -- oddly enough -- piece on bicameralism that I highly recommend. [.pdf]