There is a sort of funny things that you hear
people say that time doesn't actually exist.
And it's something that physicists argue about,
I mean physicists actually have symposia on
the subject of is there such a thing as time,
and it's also something that has a tradition
in philosophy going a back about a century.
But I think it's fair to say that in one since
it's a ridiculous idea.
How can you say time doesn't exist when we
have such a profound experience of it, first
of all?
And second of all, we're talking about it
constantly.
I mean we couldn't get – I can't get through
this sentence without referring to time.
I was going to say we couldn't get through
the day without discussing time.
So obviously when a physicist questions the
existence of time they are trying to say something's
specialized, something technical.
Einstein offers, Einstein or maybe I should
say more properly Minkowski, his teacher and
contemporary, offers a vision of space time
as a single thing, as a four dimensional block
in which the past and the future are just
like spatial dimensions, they're just like
north and south in the equations of physics.
And so you can construct a view of the world
in which the future is already there and you
can say, and physicists do say something very
much like this that in the fundamental laws
of physics there is no distinction between
the past and the future.
And so if you are playing that game you're
essentially saying time as an independent
thing doesn't exist.
Time is just another dimension like space.
Again, that is in obvious conflict with our
intuitions about the world.
We go through the day acting as though the
past is over and the future has not yet happened
and might happen this way or it might happen
that way.
We could flip a coin and see.
We tend to believe in our gut that the future
is not fully determined and therefore is different
from the past.
But physicists will say, and it's certainly
true that a lot of things that we feel in
our gut turn out not to be right.
We feel in our gut that we're sitting on a
flat plane on a surface of something that's
immobile.
And if a scientist came along and told you
that no you're actually on the surface of
a giant spear that's spinning at high speed
and hurtling through space, and by the way
there's no difference between up and down
except any illusion that's created by the
force of gravity, well you'd have to do some
radical readjustment of your understanding
of the universe to accept that your first
intuitions weren't correct.
And so if a physicist comes to me and says
do some readjustment.
Face it, the future looks different from the
past to you but actually physics tells us
it's the same, I at least acknowledge that
I have an obligation to take that seriously
to listen to it.
And physicists do argue about these things
and it's fair to argue about it.
And it's an argument that I take a position
on in my time travel book because I felt I
had to or maybe I had a position and yet it's
got to be a qualified position.
And that's what I recommend to readers of
science fiction and to physicists to remember
that your views of these things are provisional.
