also joining me a remarkable group of scientist, john brust of colombia surgeons. masud husain at the iversity of college london and senior fellow of the welcome trust, richard track o back. and oncegain, my cohoss dr. eric kandel, he is a nobel laureate, professor at colombia university and howard hugheses medical investigator. we begin our conversation asking this question, so what's our subject tonight. >> last time we considered consciousness. today we are going to consider selective defects in consciousness. these are called agnosias. people wi visual agnosia, for example, can see an object quite well, but can't name it. they don't understand what it is used for. and the whole idea of agnosia is a fascinating history. amazingly enough, the term was coined by sigmund freud. we think of sigmund freud as the founde of pshoanalysis and the interpretation of dreams, sort of the founding text of that. that was 1900 but for about 15 years before that he was a great neuroan at mist and fine clinical neurologist and in 1891 he krot a classic text on aphasia, disorders