interstellar, i am sure a lot of you saw, producer and scientific advisor, very serious the best, kempthorne of caltech - kip foreign. i would say impossible. my story is really about how the idea develops on parallel tracks and not just the idea of time travel but a whole assortment, a whole assortment of ways of thinking about time that suddenly became unsettled and thrown up for grabs. so philosophers were worrying about time as they always have but now they were worrying in new ways because they were reading albert einstein. >> a schoolboy in munich when hg wells wrote this. >> soon after, philosophers had to deal with ideas of relativity coming at them from left field and there were philosophers who said let's examine this. let's look at this fantasy by hg wells and analyze that philosophically. >> what about standing philosophy? >> philosophy before einstein took over had a view of time. william james thought a lot about time. henry baird thought about time. they were talking about the psychology of time and interested in questions that interest all of us still. how do we perceive time? why is ou