After some time trying to think about almost nothing, the last 24 hours have been an alarm call. As others come out of hibernation too, they post interesting stuff and Radio 4 provoked me with a discussion on facts and truth. Now Marc Cooper is at it, with difficult links about computation and I’m all on Edge https://www.edge.org/response-detail/26733
Before I read about “discrete tensor networks”, I need to write down my own ideas about time, so I will know in the future what I thought, before my mind was changed.
I am ill-equipped for this task, having only 1 term of university maths to my name so I intend to talk in vague, abstract terms that are hard to argue with.
Much of physics is very dependent on Time, like almost all of computer science and business management theory. You can’t have change without time, it seems. Einstein talked about space-time, mostly in the language of mathematics. I can just about order a beer in math(s) but I can’t hold a whole conversation. I know what the first 3 dimensions are: left-right, up-down and back-forward. My personal model of the 4th dimension is that same space in continuous state-change through time. There are a few things I’m not happy about:
- There is no evidence that time is either continuous or constant.
- We only have evidence of time being a one-way dimension.
- What the heck does ‘continous state-change’ mean? Is state a particle or a wave? Make your mind up, physics!
- There’s that troubling many-worlds interpretation of the universal ‘WAVE’function (which I don’t understand either) which says that everything that might have happened did, in other universes. I don’t like this. Yes, that’s my entire justification – I don’t like the conclusion of a thought process I don’t even understand. It doesn’t feel right.
I’ve been learning about the functional programming language Clojure which does not ‘mutate (change) state’. It doesn’t have ‘variables’ like the more common imperative languages such as FORTRAN, BASIC, C, Java or Python. In Clojure, data flows through functions and is transformed from one form to another on the way. It is basically magic. In a pure functional program, no state is changed. State-change is called a “side-effect”. Sadly, side-effects are required to make a program do anything useful in the real world. Arguably, the purest magic is encapsulated in the world of mathematics and the physical world is a messy place that breaks things.
Clojure models time. It does not model the real world by replacing the current value in a variable and throwing the old value away but by chaining a new value onto the end of a list of all previous values.
Now let us extend this idea ‘slightly’ in a small thought-experiment, to a 3-D network of every particle state in the universe.
Space-time now has 2 regions:
- The past – all historic states of those particles as a theoretical chain of events
- The future – all possible future states of the universe; effectively an infinity of all possible future universes that could exist, starting from now.
Which brings us to what I mean by ‘now’ – a moving wave at the interface between the past and the future, annihilating possible future universes. Time becomes a consequence of the computation of the next set of states and the reason for it being a one-way street becomes obvious: the universe burned its bridges. Unless the universe kept a list, or we do, the past has gone. Time doesn’t need to be constant in different parts of the universe, unless the universe state ticks are synchronous but it seems likely to be resistant to discontinuities in the moving surface. I imagine a fishing net, pulled by current events.
It’s just an idea. Maybe you can’t have Time without change.
[ Please tell me if this isn’t an original idea, as I’m not very well read.
I made it up myself but I’m probably not the first. ]