The Great Unknowable

It doesn't take much to realise that all is not as it seems. There is this naive view of reality, that we are essentially a brain looking out on a real material world. But the brain structures our experience in a profound way. The givens we have of space and time and left and right and in here and out there, all those are created by the brain as a way of ordering and making sense of our experience. 

This isn't just an interesting philosophical idea: just read Oliver Sacks' The Man Who Mistook his Wife for a Hat, a series of case studies of people in whom these basic brain structurings of experience have broken down, and it will shake you, as it shook me in my 20s. This life really is the Great Dreaming, and behind it all is the Great Unknowable.