Monday, February 11, 2013

McTaggart on the unreality of time

One version of McTaggart's argument for the unreality of time is:

  1. If time is real, there is change.
  2. If there is change, there is fundamental change, and it is the change of events or instants from future, to present, to past.
  3. There is no fundamental change of events or instants from future, to present, to past.
  4. So there is no change.
  5. So time is not real.
(Here, "past", "present" and "future" are understood as incompatible. Thus, "past" and "future" mean wholly past and wholly future.) I am dubious of (2). But I think (3) can be defended in the following way, inspired by C. D. Broad (I think).

We need three principles:

  1. If something undergoes non-Cambridge change from being F to being non-F, then at some time it exists and is F and at some time it exists and is non-F.
  2. Cambridge change is never fundamental.
  3. Everything that exists is present, and neither past nor future, when it exists.
  1. Nothing exhibits a non-Cambridge change from being future to being present, or from being present to being past, or from being future to being past. (6 and 8)
  2. Hence nothing fundamentally changes from future, to present, to past. (7 and 9)

I think the contemporary A-theorist should deny (2). And most do.


Alexander R Pruss said...

I just revised the post a little to remove something that seemed false.

Anyway, it occurs to me that an A-theorist could hold to a thesis that's almost like the one the argument rejects. Thus, instead of taking the fundamental change to be a change of an event or time from future to present to past, one could take the fundamental change to be a change of the cosmos from having that event or time in the future to having that event or time in the present to having it in the past.

Dagmara Lizlovs said...

Time is just this strange thing. I don't think we really get it although it has these properties:

Although each day is 24 hours long, Friday, Saturday and Sunday go by much faster than any of the other days of the week. Monday is the longest day of the week.

When you are a kid, the time between Thanksgiving and Christmas takes an eternity to pass. If you're an adult those same weeks are over in seconds while you're freaking that you haven't got that special someone a gift and your credit card is maxed out.

Einstein spent a lot of time thinking about time and relativity. For all that effort the most he can say was "When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity."

When I am out deer hunting time just changes in character all together. When I sit up in a tree stand and I become as still as possible I find that there is no past, no future, there is only the present, and it feels that time itself has stopped. This does make Friday, Saturday, and Sunday (we are allowed to hunt on the Patuxent River Naval Air Station on Sundays) just as long as Monday.