Richard Feynman discusses why there is a difference between the past and the future, in this clip from his legendary 1964 lecture series at Cornell: The Character of Physical Law. youtube/watch?v=-Km7-6-J81k It’s well worth taking 45 minutes out of your day to hear Dr. F explain why the workings of nature unfold in one direction. You see, while we innately know that the future is different from the past, and so much of our conscious experience is built around the fundamental just-so-ness of time moving forward, the equations of physics describing phenomena from gravity to friction can be run in either direction without breaking the rules. Yet irreversibility is what we observe. That’s where entropy and probability come into play. When we take into account complex systems, like the jiggles and wiggles of the uncountable atoms that make up our bodies and this chair and my coffee and our world and even out to the scale of the universe itself, there is simply a greater chance that things will become more disordered than less. It’s not that the universe can’t run in reverse, it’s just that there are so many other ways for it not to. Or as Feynman says, nature is irreversible because of “the general accidents of life”. He had a mystique that came in part from sheer pragmatic brilliance–in any group of scientists he could create a dramatic impression by slashing his way through a difficult problem–and in part, too, from his personal style–rough-hewn, American, seemingly uncultivated. It is obvious to everybody that the phenomena of the world are evidently irreversible. I mean things happen that do not happen the other way. You drop a cup and it breaks, and you can sit there a long time waiting for the pieces to come together and jump back into your hand. If you watch the waves of the sea breaking, you can stand there and wait for the great moment when the foam collects together, rises up out of the sea, and falls back farther out from the shore — it would be very pretty! Transcript here informationphilosopher/solutions/scientists/feynman/past_and_future.html
Posted on: Wed, 17 Dec 2014 17:05:07 +0000