The Past and the Future.
The future grows upon the present from the roots of the past.
Its well known that time has a direction from past to future.
The past is what happened before the present and the future hasn't happened yet.
Say I spill my cup and water runs across the table and onto the floor.
I could film that and then run the film backwards. The water would seem to gather on the floor and then leap to the table and flow into the glass which would then stand up and knock my hand.
This never happens.
It can't happen.
One source of the asymmetry is that gravity is an attractive force. Masses attract each other and that is asymmetric.
The film has no gravity. It's just a sequence of pictures that can be presented in order and that presentation can be symmetric.
Probability provides another source of asymmetry. There's a bit of a tautology there; if an event is more likely to happen than not happen then that's asymmetric on the face of it.
Roger Penrose in The Emperor's New Mind uses the example of a gas released in a corner of a room (imagine opening a box to let the gas out), By just random motion the gas would fill the room. There is, as is often said, a finite chance that random motion could move all the gas particles back into the box. The probability of that happening is very very low.
It doesn't happen.
Consider LaPlace's Demon; a theoretical construct that knows the position an momentum of every particle in the universe. Such a demon would be able to predict the state of the universe at any time in the past or future and LaPlace used the idea to illustrate causal determinism.
Causal determinism considers the future to be fixed just like the past is. Since the future is fixed it can in principle be predicted.
In the 20th century that idealistic concept crashed into experience. Quantum mechanics, for one thing, was showing that for subatomic events only probabilities of outcomes could be predicted - not actual outcomes. To know an actual outcome you need to observe it.
Turned out that that is a fundamental thing - not a problem of intractable calculations. For instance, the math showed that if you know the position of something to infinite accuracy you lose all information about it's momentum.
The math of gravity and orbital dynamics isn't very complicated on some levels. If you have a system of 2 bodies orbiting each other you can basically predict their positions far into the future from the equations.
With 3 bodies you can't. For that many you have to resort to stepwise approximations which works (after all - people do land on asteroids these days) but those approximations don't predict far into the future.
The many examples of chaos theory show the same phenomenon from a different direction. These are simple mathematical systems with unpredictable results.
These examples of unpredictability contradict causal determinism in a fundamental way.
It means that the future does not exist. The universe changes on a local scale in predictable ways but there are always influences impinging that don't originate locally.
In fact a similar thing applies to the past. We can't really retrodict the past from what we know of the present. But the past leaves various sorts of evidence about what happened. The future doesn't.
Let me switch gears a bit here.
I'm taking a non-credit course at UBC called Humanities 101. About half the sessions will be dealing with First Nations issues. Right now we're working up to Canada's National Truth and Reconciliation Day.
Truth be told - Canada has treated First Nations people very badly from the get go.
A year and a half ago mass undocumented graveyards were found outside of former residential schools all across the country - to our national shame.
My home province, New Brunswick, didn't have residential schools. I think that was because First Nations people in New Brunswick were largely wiped out by the time the schools were opened.
That's our past.
We can't change it.
But the future is a set of possibilities - the question is - which way will we go?
ne of the upcoming lectures will be given by a First Nations professor with the title "Imagine Otherwise". He's into story telling and myth making.
I'm more practical - I try to imagine otherwise in terms of social and economic systems that would replace the one we have now with one that serves everybody well.
Let's use the fixed past as a lesson and not go there again.
What do you think
I open the floor.
I present regular philosophy discussions in a virtual reality called Second Life.
I set a topic and people come as avatars and sit around a virtual table to discuss it.
Each week I write a short essay to set the topic.
I show a selection of them here.