Time is a local entropic anisometry in the phase space of possible worlds.

By "entropic anisometry" I assume you mean entropy gradient in the forward time direction, aka the 2nd law of thermodynamics? You realize that's circular, right? You can reduce the direction of time to entropy gradient (maybe), but you need to have time before you can talk about its direction. The 2nd law already assumes it.

The dimension across which that gradient occurs is a dimension of the phase-space. The gradient gives directionality to a span across that phase-space. Without that directionality, a span of the phase-space wouldn't be recognizable as time, so the existence of that gradient in the phase-space is what constitutes the existence of time as we mean it.

Time is what a clock measures.

Time is a local entropic anisometry in the phase space of possible worlds. — Pfhorrest

This is a path which few may tread. The poetry of science. :chin:

Well it's either that or sort of like a ball of timey-wimey, wibbly-wobbly... stuff.

The trouble is, you think you have time - Buddha.

The distinction between the past, present and future is only a stubbornly persistent illusion-Einstein.

All I know for sure is that the present, or consciousnesses in the present, can influence consciousnesses in the past. I know, because I've achieved this.

Time is a local entropic anisometry in the phase space of possible worlds. — Pfhorrest

Time is what a clock measures. — A Seagull

I love how these are both excellent but also completely different answers.

The dimension across which that gradient occurs is a dimension of the phase-space. The gradient gives directionality to a span across that phase-space. Without that directionality, a span of the phase-space wouldn't be recognizable as time, so the existence of that gradient in the phase-space is what constitutes the existence of time as we mean it. — Pfhorrest

Let's not put the cart before the horse. "Span across phase-space..." - which phase space? The phase space of classical thermodynamics, apparently. You need to start with the framework of thermodynamics, which, as the name suggests, involves time. That is the important bit. That the positive direction of the time is conventionally chosen as the direction in which entropy increases is almost an afterthought. The essence of this definition is that time is implicitly defined by classical thermodynamics. Which is OK as far as it goes, but we need not define time so narrowly and specifically; we can generalize this definition by stating that time is implicitly defined by dynamical laws of nature.

Time is what a clock measures. — A Seagull

Great. Now define clock and measurement without referring to time.

Time is what a clock measures. — A Seagull
Great. Now define clock and measurement without referring to time.

I don't need to define 'clock' all I need to do is teach you how to make one.
For 'measurement' read 'observe'. — SophistiCat

I think you're missing the point of where I'm going with this.

A phase space, or configuration space, doesn't have to imply anything about time being presumed simply to conceive of that space. It's just a spatial representation of all the different possible states that a system could be in.

A span across such a phase space is thus a pattern of change: the system moving from one state to another through a succession of intermediate states. This is still before we have constructed any notion of time, just a span of possibilities, without any particular directionality to them; we could, so far as we've conceived thus far, scrub back and forth across that pattern of changes willy-nilly.

Time is most generally a measure of changes in the universe, so a span of time is a span of some sort like that, through the phase space of the universe, with every possible point in that phase space representing some possible state of the universe.

But time as we normally conceive of it is directional, so not just any span of the phase space counts as a span of time as we normally conceive of it. A universe at maximal entropy, for instance, may find itself wandering around through a bunch of possible states in no particular pattern, sometimes even repeating the same state, but we wouldn't normally describe that as time running forward and backward in time in such a universe. Rather, time has effectively stopped in such a universe: all those different maximally-entropic states are "the same time", because they're all the same distance along the direction through the phase space in which we reckon time to point: the direction from less entropic states to more entropic states.

The phase space of the universe being more entropic in one direction and less entropic in another is an anisometry: it's not the same in both directions. But the phase space is not globally more entropic in one direction and less entropic in another, so that anisometry is only local. You could look along the less-entropic ("past") direction until you hit a local entropic minimum, and then if you keep looking further in that same direction, you'll see entropy going up again, so locally (in the phase space) that direction is now "the future", even though it's the same direction that elsewhere (in the phase space) it's "the past". That local entropic minimum is "the beginning of time" from the perspective of states on either side of it.

We reckon less-entropic states as "past" and more-entropic states as "future" because memory-formation, like all processes, necessitates an increase in entropy, so the states of the universe that we remember are necessarily less entropic than the current state of the universe, and as we project patterns in those memories beyond the present, we construct an idea of the future.

There are necessarily more high-entropy states than low-entropy states though, so for every point in the phase space, more adjacent points are "immediate possible futures" than are "immediate possible pasts". Because of this asymmetry, possible pasts converge, while possible futures diverge. The further into the past you look, the more determined the universe at that time is. I.e. there are fewer possible states of the universe connected to the present state of the universe through incremental steps through the phase space toward less-entropic states, the more steps you take in that direction. In the limit, there is only one local entropic minimum, one beginning of time. But the further into the future you look, the less determined the universe at that time is. I.e. there are more possible states of the universe connected to the present state of the universe through incremental steps through the phase space toward more-entropic states, the more steps you take in that direction. In the limit that direction, you get the heat death of the universe, the "end of time" even though it's not the end of change, because all change is now inconsequential and directionless, no state of the universe is a possible future, they're all either equally present or else past.


(Oh and as for the "possible worlds" bit, that's because I consider this a form of modal realism, but with possible worlds more like Kripke's than like Lewis'. Lewis' "possible worlds" are more like time-lines in this model, while Kripke's possible worlds are more like possible configurations of the universe, points in the phase space, in this model. "Accessible possible worlds", in Kripke's terminology, are basically synonymous with "futures" in this model; other non-accessible possible worlds are either pasts relative to the actual present, or else counterfactual, "alternate timelines".)


FWIW, this isn't at all contradictory with "time is what a clock measures". A clock is just a system that undergoes routine, patterned changes, which is excellent for measuring distances across a configuration space, just like a ruler with its routine, patterned markings is excellent for measuring distances in ordinary space.

Feedback/forward between two events observed by a conscious awareness (i.e., not necessarily an observation by cognition or an agency). Then, because an artifice invented by a specie in the unknown expanse of universe, known as a mechanical clock, obeys no feedback from any non local environment...or any environment not acknowledged by a single specie...couldn't possibly be the truth of what is time. Time is nonlocal, and local. Not either or. "To be is to be perceived."

I'll show you later.

There you go.

the ancient greeks had two concepts of time. there is chronos, the titan, which is how most the west thinks of time, organized in equal sized divisions. And there is Ion, or Eon, whereby time is organized in chunks, sometimes as long as epochs, that may be of any length, separated by significant events of the gods.

the iteration of events. Time can only be accurately measured in a small subset of the universe where the physical clock is going the same speed or approximate same speed as that subset of the universe. Special relativity....

I offer two similar definitions given by Charles Sanders Peirce.

Time is that diversity of existence whereby that which is existentially a subject is enabled to receive contrary determinations in existence. — Peirce, c. 1896

Time is a certain general respect relative to different determinations of which states of things otherwise impossible may be realized. Namely, if P and Q are two logically possible states of things, (abstraction being made of time) but are logically incompossible, they may be realized in respect to different determinations of time. — Peirce, c. 1905

When you ask something like "what is time?" you are asking "how do we use the word 'time'".

Now, any and all of the definitions set out in words here are at the best incomplete, and more likely simply misleading. For example @fhorrest strings together big words, and immediately @SophistiCat puts those words in contention. @A Seagull attempts to set out an example and has this thrown back at him, again by @SophistiCat... Worst, @3017amen seems to think you are mistaken, arguing form authority.

Hence my showing instead of stating.

Point being, you already know what time is, since you are a competent user of English. And indeed, the questions you ask are about time, hence presuposing that knowledge.

You will get better answers to some of your questions from physicist than from philosophers.

My advice would be to try a science forum. Or read a book.

I'd say time is perceived change. Change is ubiquitous. Change requires an interaction, a term that implies the existence of that which interacts. Thus, I'd say time is perceived change which is brought about by the interaction of two or more objects. The perception of change is carried by the interacting objects (not a third party observer); and because there are no two things that are the same, each perception of change is different; but because the interaction is the same for the interacting objects, their perceptions of change must be related by some factor.

A Seagull attempts to set out an example and has this thrown back at him — Banno

Dream on!

To speak of time is to speak of the soul. Not only is everything animated in it, but it animates everything. It's such a vital part of reality that nothing can be completely disassociated from it. Everything is time, and everything is the soul, and it's all one grand idea in the mind of God, which is our own minds that dream.

What I'm trying to say is that time is the thing that causes time. It's illusory, but not an illusion. Appearances are always deceiving.

A phase space, or configuration space, doesn't have to imply anything about time being presumed simply to conceive of that space. It's just a spatial representation of all the different possible states that a system could be in. — Pfhorrest

But before you can conceive of a phase space, you have to conceive of a theory that gives rise to that phase space. The phase space is just a slice of the theory; you need to lay out the theory first. And as you do, time will already be there, even if you haven't specifically identified it as such. So first you build the stage and place the backdrop and the decorations, and gather actors and give them their parts, and set the play in motion. And then you can point to one of the actors and say: that is time. The play will not make sense without this central character, but neither will the character make sense outside the context of the play. The character of time emerges from the narrative of a physical theory, which in turn needs this character for its coherence. There is a mutual dependence here that makes straightforward reduction ("A is nothing other than B") impossible.

It's the same with time and clocks (@A Seagull): you can't conceive of a clock without already operating with a notion of time, but neither can you conceive of time without representing it using a clock, a physical process of a certain kind. The two notions are mutually dependent but not reducible to each other.

You (@Pfhorrest) make time specifically a thermodynamic actor, but of course time is present in other physical theories as well. It is just that continuum and statistical thermodynamics happen to be the only theories that we have in which time has a preferred direction. At thermodynamic equilibrium time disappears in the description of the macrostate, but it will still have a part to play at other scales and in other theoretical frameworks. It just won't have an overall preferred direction. ("Join the club!" says space. Space also has preferred directions, but only at some scales in some theoretical frameworks, e.g. in Earth-bound sciences.)

I offer two similar definitions given by Charles Sanders Peirce.

Time is that diversity of existence whereby that which is existentially a subject is enabled to receive contrary determinations in existence. — Peirce, c. 1896


Time is a certain general respect relative to different determinations of which states of things otherwise impossible may be realized. Namely, if P and Q are two logically possible states of things, (abstraction being made of time) but are logically incompossible, they may be realized in respect to different determinations of time. — Peirce, c. 1905 — aletheist

These definitions will fit any parameter in a parametric description: position in space, population density, Mach number, household income, etc.

Point being, you already know what time is, since you are a competent user of English. And indeed, the questions you ask are about time, hence presuposing that knowledge. — Banno

It is fine to ask for an explanation of something that you already know and have a word for; we do that all the time, whether in physics or in philosophy. But when asked out of context "What is X?" you should reply back: "Why do you ask?" What sort of an answer are you looking for? A reductive definition? In terms of what? A contextual explanation? In what context?

All I know for sure is that the present, or consciousnesses in the present, can influence consciousnesses in the past. I know, because I've achieved this. — neonspectraltoast

Is this to say that perception of past events are dictated by current mood, attitude or state of awareness? As in if I were to enjoy something in the past which I later discovered was a lie and now only see this past deception as a waste of my energy or pointless? Because we only store memories in the present. So I would imagine memories of the past are very much influenced by present state

a superb demonstration of "later"

You will get better answers to some of your questions from physicist than from philosophers.

My advice would be to try a science forum. Or read a book. — Banno

Except the point of my question was not whether this is the ideal place to search for accurate knowledge on "time". My question was about your opinions. Your views. "You" are implicit in my questioning. So in fact this is exactly the right place for me to ask such a thing. And I got my diversity of replies...what i came for. Everyone can read a physics book on time....but i wanted to know... how does a selection of strangers articulate their experience of this phenomenon. Is it like me? Completely different to mine? Can I learns something from them?

And I did. Even a demonstration which I found very amusing.

No. The perception of past events has some component that reaches across time and space and can and does influence past events. The events themselves don't change, but you, in the present, always influenced them in the way that you did.

The future already exists, and the past exists in the future. The present obviously influences the future, but the past has a future as well.