Time is homogeneous sequentially-composable determination

post by TsviBT · 2023-10-08T14:58:15.913Z · LW · GW · 0 comments

Contents

  Reasons to talk about time
  Bearers of time
  Relationships between time-courses
    Canonical global time
    Canonical local time
    Forced shared time
    Criss-crossing timecourses
      Multiple tributaries
      Loopy time
      Directly opposed time
  The thingness of time
    Past, present, future
    Determination as the core of time
    Sequentiality
    Homogeneity
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[Metadata: crossposted from https://tsvibt.blogspot.com/2023/06/time-is-homogeneous-sequentially.html. First completed June 30, 2023.]

Time is the character of courses of events in which determinations——the ways that one event determines the next——are uniform across events and across composing determinations.

Thanks to Sam Eisenstat, Scott Garrabrant, Brady Pelkey, and Kyle Scott for related conversations.

Reasons to talk about time

Why talk about time? Here are some key concepts that are bound up with time, and so make demands on the understanding of time:

See also "Saving Time" [LW · GW] and "Finite Factored Sets" [LW · GW].

Bearers of time

Here are some overlapping aspects of the cosmos that have some timelikeness:

Relationships between time-courses

Canonical global time

In some dynamical systems, there's a unique natural global time.

Canonical local time

Forced shared time

Stuff goes on in the world, regardless of what you think, on its own time, and then that stuff can impinge on you. Time courses forcibly (or "objectively") interact with each other.

Criss-crossing timecourses

Timecourses——channels in which timelike sequences of events go on, connected in a timelike way——can cross each other.

Multiple tributaries

Timecourses can intersect in an event, coming from different directions.

Loopy time

A timecourse can seem to go in a loop, so that something is in its own past.

[Modified from https://pmontalb.github.io/TuringPatterns/.]

Directly opposed time

Timecourses can be directly opposed, flowing in opposite directions and colliding with each other.

The thingness of time

Is time a Thing? Looking through the above list of timecourses, are there central shared features that lead into other relevant shared features?

Past, present, future

The past is something you can learn from, remember from; it's something you could have seen or otherwise sensed. What's past is in a sense locked in, irreversible; it can't be changed that, on Friday June 30 2023 at 10:13, I was typing this sentence. The past can also lock in or irreversibly cause enduring features of the cosmos. E.g. if a hard-drive is dissolved in a vat of acid, the data it uniquely stored is irretrievably lost. In some cases the past is something you could respond to, diagonalize against, erase, countervene, or reverse——you can react to affect the past's effects, though you can't affect the past. The past gave rise to you, made you what you are.

The future is something you can affect. It's something you can't see and can't have seen, except in imagination (or by waiting). It's something that is not locked in, that could be changed. You give rise to the future and to your future self.

The present is what you immediately——without mediation——sense and act upon. It's where plans cash out into actions, where actions are taken; it's the purview and responsibility of the actor. It's the last chance to affect things, where future becomes past.

Determination as the core of time

Time involves succession: an event B comes after another event A, and A comes before B. Why do we say "after", instead of just saying that there are two events, A and B, which are separate, just like two simultaneous events are separate?

One answer is: because we compare A and B against other processes, such as the spinning hands of a clock, and see the ordering of A and B relative to the familiar ordering of the clock-hand positions. This says something about when and how we say "after", but it doesn't say why we say "after".

Another answer: We say that B comes after A when A can affect B. If A determines, affects, or causes B——then A comes before B. If B depends on A, or if B is a consequence or implication of A, or if B is decided, determined, committed to, or locked-in by A——then B comes after A.

"Affect" is not quite the right word. It seems to emphasize physical causality and exclude some timecourses, e.g. logical constraints propagating or discoveries unlocking other discoveries. Instead:

Time is the course of determination.

This opens the black box of time and takes out a slightly different, still mysterious, black box called "determination". The question "What is determination?" or "How should I think about determination?" is almost the same question as "How should I think about counterfactuals [? · GW]?". The emphasis of "counterfactuals" is on the agent: What if I did this or that? What would then come as a consequence of my action? "Determination" emphasizes some partially objective structure——the reality that bites back, the reality that you can't get around just by having something different in your head. I suspect both forces have to be integrated: the root of determination in the actions of an agent, and the sturdy cage/scaffold of non-mind-determined reality.

Quoting the closing paragraphs of "Timeless Decision Theory" by Eliezer Yudkowsky:

I wish to keep the language of causality, including counterfactuals, while proposing that the language of change should be considered harmful. Just as previous statisticians tried to cast out causal language from statistics, I now wish to cast out the language of change from decision theory. I do not object to speaking of an object changing state from one time to another. I wish to cast out the language that speaks of futures, outcomes, or consequences being changed by decision or action.

What should fill the vacuum thus created? I propose that we should speak of determining the outcome. Does this seem like a mere matter of words? Then I propose that our concepts must be altered in such fashion, that we no longer find it counterintuitive to speak of a decision determining an outcome that is "already fixed." Let us take up the abhorred language of higher-order time, and say that the future is already determined. Determined by what? By the agent. The future is already written, and we are ourselves the writers. But, you reply, the agent's decision can change nothing in the grand system, for she herself is deterministic. There is the notion I wish to cast out from decision theory. I delete the harmful word change, and leave only the point that her decision determines the outcome——whether her decision is itself deterministic or not.

Sequentiality

If A determines B and B determines C, then A determines C.

This transitivity formula specializes to the various timecourses. If A {logically implies, physically causes, gives rise to by emergence, unlocks the discovery of, structures the design of, sets the preconditions to decide, unfolds into, ...} B and B does the same to C, then A does the same to C.

The transitivity of determination sets up a genuine sequence of events connected by determination. The sequence [A,B,C] isn't just a collection, it has an ordering that consistently relates all the elements of the sequence to each other. What we call time is a time-course, a sequence of composed determinations.

Homogeneity

There wouldn't be much power in the idea of time, or determination, if there weren't anything to say about it that applied across many determinations, or many connections between events. Physical law, and generally dynamical laws, are time-invariant. The connection between an event A and a subsequent event B——the way A determines B——greatly overlaps with the connection between B and a subsequent event C. For example, the same logical laws apply when deriving B from A and when deriving C from B.

That's how clocks work: what goes on in the clock, goes on in (roughly) the same way, however much it's already gone on.

There are other invariances, e.g. the invariance of physical law with respect to space or motion, or the invariance of the laws of logical deduction with respect to a difference of axioms. Time forms ordered strands, sequences of connections. Time is the character of homogeneity in determinations that can be composed sequentially, one after the other (so to speak). If and , then also , and furthermore the way in which is like the way in which and . So we have the formula:

Time is homogeneous sequentially-composable determination.

[From https://falseknees.com/297.html.]

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