Monday, November 15, 2004

Philosophy of time

MelbournePhilosopher

Rather than summarise the physics of time, I'm just going to say this right out - I don't believe in time. You heard me - doesn't exist. So how do I explain what we all obviously experience and call time, and how did I come to this view?

Well, if you ask a modern physicist "what is time", the first answer he'll give is an analogy with position. Just as I can be to the left of something, or to the right of it, so I can be before it, or after it. Causation works along on direction only, and we call that "forward" in time. If you probe a little harder, you'll find out the time is just another variable in some maths that relates mass, momentum and location. How fast is the car travelling? 50 kilometers per hour? Oh, right that makes sense. So what's an hour? Well, an hour is about how long it takes for a car going at 50km/h to go 50 km.

That's right - the only way I know to describe time is self-referential. How, er, long does a second last? How do we know that a second is the same in all places? Actually, thanks to relativity, these kinds of questions make only a limited sense, but even then time is still just this crazy self-defined thing. Time is only ever defined in terms of motion. Here's what time really is, mathematically speaking. Time is the movement of one object, relative to the movement of another. Say I've got an incredibly reliable clock. I can judge time off it, because it's a consistent frame of reference. I can define one tick of the clock as "a second" and from that determine how far all the other objects in question move in that second. But my second is only defined here as the motion by the second hand of one interval - maybe a few mm, depending on the size of the clock.

This makes good relativistic sense, and the intuition is sound even under high velocities. No matter how fast you are going relative to other objects in space, your personal definition of time is still only understood in terms of the motion of the clock you have with you.

Time, then, is nothing other than change. Because things change with respect to other things in reliable an predicable ways, we have evolved with an innate sense of a "rate of change" that is natural. If you will, our sense of time is like an inbuilt clock, by which we judge the change of other objects.

The question "where does the past go" has the answer nowhere. The past is just the word we use to describe what the universe was like before it changes. The future is just the word we use to describe that the universe is still undergoing change.

13 Comments:

Anonymous Anonymous said...

I'd like to see you live your life as if time didn't exist ;)

11/15/2004 10:45:00 PM  
Anonymous Anonymous said...

what then is "change"?

11/16/2004 02:02:00 PM  
Blogger MelbournePhilosopher said...

Well, change still means change. Something that was a particular way changes, and after the change is different. I think you mean "how does change happen" if there is no time? Well, there is still a causal chain. I'm not saying that change can't happen, but arguing that the feeling of time that we have is the result not of motion through a time dimension, but just by experiencing change. When people use time like they use a location, and especially when they start talking about determinism, I think there's a mistake in there. If you can describe time as just resulting from the causal chain of events rather than being an actual dimension of reality, you have simplified your ontology, which is a good thing. I think time is a mathematical convenience rather than a philosophical necessity...

11/16/2004 03:46:00 PM  
Blogger thesocialworker said...

I see you've been listening to philosophytalk.org

I agree with you, I don't believe time exists 'out there' in some sort of objective fashion. Man created time, like they created science, neither of which is set in stone. I always find in interesting to think back to how life would've be experienced when people didn't have access to time measuring tools. How did people know when to stop working!?

11/16/2004 07:09:00 PM  
Anonymous Anonymous said...

"and after the change" ... your reply about change was replete with references to time!

I wasn't asking "how" change happens, I was asking you to define it.

My definition of change would be something along the lines of "change over time". You defined time as "nothing other than change". If you believe this, it seems to me that you need to come up with a definition of change that does not rely on time.

11/16/2004 11:32:00 PM  
Blogger MelbournePhilosopher said...

Sure, I referred to time - how else do you expect me to describe how my position is different?

How can a definition of "change" be "change over time". That's like defining n as n + 1, it's circular.

Change is just what we say when an object becomes different. The idea of time as being how we experience the causal chain, rather than a physical dimension, does not preclude this. Change is just an object becoming different as a result of some cause.

11/16/2004 11:39:00 PM  
Blogger Ole said...

Might I add that change requires time! ... nothing changes instantly, all change takes time, so the concept of time must exist for change, I believe they are undeniably linked. Who can change anything without some time to do it?

http://wisewordsbyole.blogspot.com

11/17/2004 11:39:00 AM  
Blogger MelbournePhilosopher said...

Things change not merely instantly, but an infinite number of times during any time interval. The concept of a "moment" in time in which all objects are in a particular state of being is a false tool of visualisation. Nobody can stop 'time', it rolls on inexorably.

If change cannot happen instantly, then nothing can ever happen. Consider Zeno's paradox (google will be able to tell you more). If all change took some finite time, we could never achieve the infinite number of changes required to move from A to B. With or without time as a spacetime dimension, understanding how change occurs is a mind-spin. Understanding time as a mathematical relation for change as opposed to something that is understood spatially is not unreasonable, even though it's not really the generally accepted view. But most people don't try very hard to talk about the nature of time, they are content to rely on the equations without considering the metaphysics.

11/17/2004 12:24:00 PM  
Blogger mh said...

I wonder if it might not make just as much sense to think of causation going the other way, namely "backwards" in time.

It seems to me that the conventional understanding is anthropocentric: we talk this way because we like to know about the causes required to bring about certain effects.

11/21/2004 10:07:00 PM  
Blogger MelbournePhilosopher said...

I guess it's also relevant to ask why the present is priveledged in our consciousness, if time is just a spatial thing. Under my idea, it's priveledged because the past doesn't exist and anything other than the historic record, and as such you really can't change the way things were. Under other ideas of physics, it looks like reverse causation is plausible, but lacking concrete examples it's hard to imagine what it would be like.

Cheers,
-BM

11/22/2004 01:36:00 PM  
Anonymous Anonymous said...

I am not a philosopher nor a physicist. I can't talk on the same level as most of you brilliant folks! But I just had to add my 2 cents. I have been questioning time for a number of years. I've done some reading (Jacob Needleman's "Time and the Soul" most recently, and again). My gut feeling is that linear time is some sort of lie. I can't describe exactly how this works, but there you have it.

12/15/2005 10:36:00 AM  
Anonymous Anonymous said...

Definition: "Change is just an object becoming different as a result of some cause."

Why couldn't the cause be time?

"Causal Chain": experiencing change in objects, in space, from an infinite chain of events, not a 4th dimension.

Time Flow: experiencing change in objects, in space, from an infinite chain of events. 4th dimension backed up by mathematics. "Understanding time as a mathematical relation for change... is not unreasonable"..."time is a mathematical convenience".

"time is just a spatial thing"
causal chain is just a spatial thing

Looking for your point?...because, i thought it was that time does not exist.

10/01/2006 10:44:00 AM  
Blogger MelbournePhilosopher said...

Because if time exists, time is just a dimension like any other spatial dimension. Move the reference point along it, and things are in a different spatial configuration.

A dimension is not a cause. It just seems like a problem brought about by a turn of phrase.

There are too many "why" questions where "time" is an insufficient answer.

Cheers,
-MP

10/02/2006 12:10:00 PM  

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