Does the idea that everything is made of causes and effects meaningfully constrain experience? Can you coherently say how reality might look, if our universe did not have the kind of structure that appears in a causal model?
Physicists tell us that reality is, at the lower levels, described by differential equations. Those describing the temporal evolution of systems are generally hyperbolic differential equations. That is, they have microscopic causal structure: the properties at a point (x,t+dt) depend on the properties only in a small, finite neighbourhood of x at time t. This is what allows larger scale events to be described more abstractly in terms of causal graphs. (A known problem here is the time-symmetry of all these equations. I don’t have a solution to that either.)
Some have speculated about the very finest scale being discrete, with fundamental laws of temporal evolution such as those of cellular automata or graph rewriting. That would also provide the fundamental causal structure from which causal structure on the macroscopic level emerges.
A universe whose fundamental laws were all elliptic differential equations—those in which a change in boundary conditions in one place changes the solution everywhere at once—would not support causal reasoning. Everything depends on everything else and none of its emergent phenomena would be describable by sparse causal graphs. I’m not sure you could have agents within such a universe, for it to look like anything to them, or any notion of time, but we can imagine such universes from outside.
Does the idea that everything is made of causes and effects meaningfully constrain experience?
A causally disconnected event would not affect our experience, so no, it does not constrain our experience.
But it wasn’t meant to: it was meant to constrain our maps, not our experience. To stop us from believing meaningless statements.
Can you coherently say how reality might look, if our universe did not have the kind of structure that appears in a causal model?
Every causally separated group of events would essentially be its own reality.
Does the idea that everything is made of causes and effects meaningfully constrain experience?
No. For any set of observations O1, O2, …, O_N, you can construct an overprecise causal model that links some central cause to nodes O1, O2, …, O_N. [That is, our causal model is: “You observed O1 because God willed it. Then you observed O2 because God willed it...”] Thus causal models can explain any set of observations. Constraining experience requires in addition some sort of Occam’s Razor that prefers simpler causal models.
Constraining experience requires in addition some sort of Occam’s Razor that prefers simpler causal models.
I’d agree with the assertion “Unknowable relationships are equivalent to no relationship”. In other words, cause-and-effect is only meaningful if we have some ability to gather information as to the nature of the relationships. Occam’s Razor is one such method, but I wouldn’t assume that it’s specifically required—we could just as easily be born with divine insight as to the cause-effect relationships.
To answer this, I need to answer another question: What would the universe look like if it did not have the structure of causal models? If I know that then I can know whether or not that universe looks different than ours.
So we’re talking about a universe where there is no A --> B causal connections. Where you can’t accurately say something like “When I eat, it causes me to be less hungry,” or even say anything, since “saying” something requires some sort of causal ability: the ability to push air in intensional patterns.
And that universe… really doesn’t look like ours. I might want to talk about a universe where there are correlations but not causations, but then how do I explain the correlations? Are they just brute facts? That seems unlikely. But even in that event, I would expect rules to break down in chaotic ways: one day, food wouldn’t make me feel nourished. And it wouldn’t be because I ate the wrong foods or something like that, it’d just be because the correlation broke down. And that really doesn’t look like our universe either. I may be wet because it was raining, but I don’t get wet merely because some ‘correlation’ between ’sunny_day” and “not_wet” broke down.
So we’re talking about a universe where there is no A --> B causal connections.
Actually we aren’t. We are talking about an universe where there are effects that happen without cause. That doesn’t mean that effects that have causes aren’t allowed.
A universe without a completely causal structure would have to have a number of effects that have no cause. (This need not apply to all effects in this universe, merely to a subset of effects). The Steady-state universe, a now abandoned alternative to the Big-bang model, may be an example; in the steady-state universe, if I remember correctly, it was theorised that small bits of matter (hydrogen molecules) appeared out of nowhere at random times, at a very low rate. This is an example of an effect without a cause.
Alternatively; consider a universe where a man suddenly appears out of nowhere in the middle of a public area. He claims to be a time traveller, from fifty years in the future, coming back in time to prevent some terrible disaster. Though his story is unbelievable, the disaster he predicts is prevented. Fifty years pass, and the time traveller is not sent back to the past (since the disaster was, after all, prevented). This does not cause a paradox (the laws of this universe are that matter can appear at any time, in any arrangement, including a person with false memories of time time travel from a non-existant future) Such a potential universe thus has an effect (the man appears) without a cause.
The examples don’t quite work. In that steady-state universe, the appearing matter subsequently interacts and so is causally connected to the rest of the universe. You just have to trace the connections backwards, and eventually you reach a stopping point. Similarly with the false time traveler: he causally affected the world, so he’s clearly part of a chain of causes and effects.
It’s a separate question to ask whether everything has a causal in-connection and a causal out-connection. Both your examples, and epiphenomal theories of mind, are meaningfully about unidirectional causal links.
Hmmm. I had been trying to consider the case where some events have no causes. Now, you’re pointing out—as I understand your argument, and please correct me if I am wrong—that the same event can be a cause, and therefore that it is a part of an interconnected causal universe.
This is an interesting argument. If I notice the existance of something, then that is a causal relationship; it exists, and this causes me to notice it by some means. Therefore, anything that I observe shares a causal relationship with the fact of its observation; if that is enough to consider it part of a causal universe, then I can only observe a causal universe. I cannot imagine anything that I cannot, by definition, observe in any manner (including by any deduction) constraining my experience.
On the other hand, I can (at least in certain imagined universes) observe effects without causes; I can observe the time traveller appearing for absolutely no reason.
I had assumed the question was “a universe where an event can have out-connection but not in-connection” (and the consciousness one was about having an in-connection but no out-connection).
In a universe with NO connections, you wouldn’t get patterns, much less emergent patterns—no atoms, no stars, no planets, no life, not even internet!
Multiple segregated causal networks would be multiple realities (I think the simplest reference would be to think about two different books or virtual worlds, although there’s actually still some connection there)
Individual events which have out-connections but not in-connections, by contrast, seems like a fairly interesting question to explore. Why DO we assume that all evens have in-connections? Why not just assume the weather is because Zeus is mad, and Zeus’ emotions are beyond the ken of mortal minds?
Individual events which have out-connections but not in-connections, by contrast, seems like a fairly interesting question to explore. Why DO we assume that all evens have in-connections?
Not all, the past doesn’t have in-connections and the future doesn’t have out-connections.
Can you explain what you mean by that? I tend to model past events as having even-further-past causes. I definitely model future events as having even-farther-future ramifications. So they’d seem to generally have both in and out.
At first thought. It seems that if it could be falsified, then it would fail the criteria of containing all and only those hypotheses which could in principle be falsified. Kind of like a meta-reference problem; if it does constrain experience, then there are hypotheses which are not interpretable as causal graphs that constrain experience (no matter how unlikely). This is so because the sentence says “all and only those hypothesis that can be interpreted as causal graphs are falsifiable”, and for it to be falsified, means verifying that there is at least one hypothesis which cannot be interpreted as a causal graph which is falsifiable. Short answer, not if we got it right this time.
(term clarification) All and only hypotheses that constrain experience are falsifiable and verifiable, for there exists a portion of experience space which if observed falsifies them, and the rest verifies them (probabilistically).
Asserting that a particular causal model is an accurate description of the universe certainly constrains experience to fit the causal model. Asserting that it is possible to accurately describe the universe with a causal model is tautologically true because a fully connected model fits every possible probability distribution. Asserting that it is possible to accurately describe the universe with a simple causal structure constrains experience to match a simple causal model. If you know that the universe fundamentally works by running some causal model, asserting that the universe runs this particular causal model predicts that you will never find a more accurate causal model for describing the universe. I’m not sure how asserting that the universe fundamentally works by running some causal model would constrain experience.
Several possible examples come to mind for a universe with no cause or effect.
First is a universe with only one thing in it, so that there’s nothing for it to be causally connected to.
Second is a universe with multiple things in it that could in principle interact but due to the set-up of the universe never actually do interact. For example, a universe of rigid particles in a void where they would interact if they struck, but the distances between all particles are too great for that to occur in the lifetime of the particles.
Third, a universe in which its entities do interact, but nothing ever changes, so there are no nontrivial correlations. Perhaps count a universe of mutually repelling particles in a void, arranged in an unchanging crystalline structure.
Fourth, more loosely, is a universe in which its entities do interact and change, but the arrangement of all the things is such that only minimal correlations arise. Perhaps a universe analogous to a closed system containing a gas at thermodynamic equilibrium.
Prescinding from those, the idea that everything in our universe is made of causes and effects constrains my expectations in that there should multiple things (check) that actually interact (check) and change (check) and have nontrivial correlations (check). Other than the continuation of such things, I can’t readily think of any sense in which the idea constrains my expectations for future experiences.
To clarify you are pointing out that without cause and effect, stars would not even form, or even baryons for that matter. A gas at thermodynamic equilibrium probably would not be conscious, so from there we can go straight for the Anthropic Principle. Otherwise the question has no real solution—like asking what a peacock would look like if eyes didn’t exist. (Handoflixue already killed this horse, though—sorry for beating it.)
My first answer is that the idea of ‘interventions’ comes from causality- if I don’t like being wet, and it’s raining, I can deploy an umbrella, and that will make me not get wet(ter) from the rain. The idea that everything is made of causes and effects meaningfully constrains actions, because an agent that understands causes can manipulate reality better than an agent which doesn’t understand causes.
But that’s just a further elaboration of what reality looks like now. It’s difficult for me to imagine a world without causality- and I don’t think that’s just because I (like most humans) am a deeply causal thinker. Causal models are just math, and so they can be imagined just like multiple spatial geometries can be imagined, regardless of what the universe’s real shape is. I think you would need to have a universe in which no causal models could be justified by the data, which would be an incredibly strange place.
And, actually, by the definition of universe you use in the post, a universe without a causal structure would just be a single node, forever alone.
If our universe did not have the kind of structure that appears in a causal model, then our reasoning would not function properly. Induction would fall completely flat, and I don’t think our brains would work right. We probably wouldn’t exist in such a world, but if we’re taking into account anthropic effects… well, I’m not even sure a human could survive long enough for a single conscious thought, since their state at time t+1 wouldn’t follow from their state at time t.
After skimming others’ replies, I’ve realised that I’ve answered a different question. To answer this one: no, but we’ve got no way of reasoning about or utilising anything else, so it doesn’t matter. That there are no uncaused causes of real things (a weaker claim) does meaningfully constrain experience, though.
If the universe were not governed by cause and effect, then we could not consistently improve our predictions of the future by observing the past, even by a little bit.
Does the idea that everything is made of causes and effects meaningfully constrain experience? Can you coherently say how reality might look, if our universe did not have the kind of structure that appears in a causal model?
No. I literally assign prior probability zero to the statement that the universe is not made out of causes and effects, because there is causal structure in Turing machines and in all Turing-complete models of computation which could make up the Solomonoff prior. Causal structure is a very broad thing—it’s just a sparse graph of interacting entities with a lattice ordering.
I can imagine a universe in which the local ordering I observe doesn’t go as far forward or back as I thought, and the true everything-is-causes-and-effects structure is pushed one layer back to something completely hidden from me. I can imagine a universe in which I’ve falsely inferred an ordering which isn’t there, and getting confused by cycles in a graph that I thought was causal. But a universe with no causality at the lowest layer—I think causality is inherent in too many things, and that after subtracting those things there’s not enough option space left to make a universe out of.
If you can’t imagine an universe that’s not made out of causes and effects than talking about such an universe is meaningless.
To be able to assign a probability zero to the statement that the universe is not made out of causes and effects you have to be able to imagine a universe that’s not made out of causes and effects.
Meaningless statements can’t be true or false. Speaking about their probability makes no sense.
I can imagine a universe in which the local ordering I observe doesn’t go as far forward or back as I thought, and the true everything-is-causes-and-effects structure is pushed one layer back to something completely hidden from me. I can imagine a universe in which I’ve falsely inferred an ordering which isn’t there, and getting confused by cycles in a graph that I thought was causal. But a universe with no causality at the lowest layer—I think causality is inherent in too many things, and that after subtracting those things there’s not enough option space left to make a universe out of.
In other words, causality is the invisible pink unicorn.
The text I quoted in the grandparent seems to be saying that even if the universe doesn’t contain causality, we can always postulate an external causality structure even if most of it can’t be observed.
Time appears to stretch backward infinitely, because local causality still looks nice. But actually it only stretches backward to now. If time was actually a straight line rather than a cycle, then one could intervene in this system and it would only change the future. But if you intervened in a cyclic system, you would find that you had changed what looks like the past.
In fact, self-consistency constraints would kick in and logically prevent you from some sorts of intervention that would make perfect sense if time stretched off to infinity—it’s like using quantum mechanics instead of classical mechanics, where classically it seems like you should be able to have any amount of energy you want.
More philosophically, we’ve run into Aristotle’s distinction between self-cause and infinite regress. And also why Bayesian networks are typically defined as directed acyclic graphs, thus putting cyclic graphs outside of the hypothesis-space.
I think I understand your distinction between infinite regress and cyclical causation, but I don’t understand why that implies a cyclical universe violates causality. To rephrase jimrandomh: that isn’t a violation of causality, it’s just a universe with cyclical time.
Well, one can still think of it causally—you can still draw a graph with arrows, at least. But it’s atypical causality.
Typical causality is like kicking a ball. The ball sits still until you kick it, and you can kick it however you like and it will roll away. But once you have loops, it’s like if the ball had to go through a portal to the past and kick itself. As soon as you try to kick the ball, the ball you would have kicked has already gone back to the past and hit itself in a way consistent with the motion of your foot, so it will feel quite unlike kicking the first ball. And in fact it is physically impossible to move your foot in a way inconsistent with the ball being the cause of its own motion, even though trying to kick the ball restricts the possibilities—or rather, being able to try to kick the ball tells you that the possibilities were already restricted...
In typical causality, the ball has a reason for moving the way it does—you can trace the motion backwards to some acceptable starting point, like “I kicked it as hard as I could toward the fence.” When you add cycles, tracing the chain of arrows back does not need to end at anything you find remotely satisfactory or even unique—“the ball moved because it hit itself because it moved because it hit itself...”
When you add cycles, tracing the chain of arrows back does not need to end at anything you find remotely satisfactory or even unique—“the ball moved because it hit itself because it moved because it hit itself...”
This is a problem with your personal intuitions as a medium-sized multicellular century-lived mammalian tetrapod. No event in this chain is left uncaused, and there are no causes which lack effects in this model. Causality is satisfied. If you are not, that’s your problem. Hell, the energy is even conserved. It runs in a spatial as well as a temporal circle, what with the ball hitting itself and skidding to a stop exactly where it was sitting to wait for the next hit. On the other hand, in such a universe quantum mechanics does not apply, because worldlines cannot split, which also removes any possibility of entropy. ALL interactions are 100% efficient.
Meditation 3:
[Hardest of the meditations, for me.]
Let us observe the difference between [post-utopian]-->[colonial alienation]
and a connected thing (say [I see you picked Ace]-->[You see you picked Ace] from a deck of cards):
In the first case, there is no way to settle an argument about whether Ellie is post-utopian or not. We would predict that it would cause arguments between people that are not settled. Anything connected to the causal web is more likely to lead to settlable arguments, at least among people behaving more-or-less rationally. It is not a perfect test, but it does suggest that I expect to see different things from connected networks and unconnected networks, like people changing their minds.
1) The universe has a joint probability distribution such that events are not independent, but so few events are independent that limiting the description to a causal one does not materially reduce the complexity of the “true” model. In this case, There would only be the joint look-up table.
2) All events are independent.
3) The universe is not well-described by the laws of probability.
The first case would make prediction pretty much impossible (since you’re never dealing with the exact same set of variables twice). “Same river” and all that. No prediction more specific than “the universe persists in some way” would be true very often on average, since there are so many possible outcomes, and no reason to believe that the next joint probability for the event you care about is similar to the last one.
In the second, you could predict roughly the proportion of events based on the proportion of past events, but there would be no discernible pattern, or result of action.
In the third, I can’t tell you what you’re likely to observe, for obvious reasons.
It would be completely random, with all events being equally likely at every point in time.
It would have no history, since the past has no effect on the present or future
You could plug a baby’s nervous system into the output of a radium decay random number generator. It’d probably disagree (disregarding how crazy it would be) that its observations were best described by causal graphs.
I think it is a mistake to tie the question of what reality is to the particulars of the physics of our actual universe. These questions are about what it is to have an external reality, and the answers to them should be the same whether the question is asked by us in our current universe, or by some other hapless inhabitants of a universe bearing a distinct resemblance to Minecraft.
I can imagine types of existence which don’t include cause and effect—geometrical patterns are an example—there are relationships, but they are not cause and effect relationships—they are purely spatial relations. I can imagine living in a universe where part of its structure was purely such spatial relationships, and not a matter of cause and effect.
Imagine a universe that is made only of ideal billiard balls eternally bouncing around on a frictionless, pocketless billiard table. Essentially the same thing as selylindi’s idea of a gas in thermodynamic equilibrium. Imagine yourself observing this universe as a timeless observer, or to aid the imagination, that it’s “time” dimension is correlated to our space dimension, so we see the system as an infinite frozen solid, 11 by 6 by infinity, with the balls represented by solid streaks inside that go in straight lines except where they bounce off each other or the boundary of the solid.
Now, this system internally has a timelike dimension, except without increasing or decreasing entropy. And the physics of the system are completely reversible, so we have no basis of saying which way is the “future” and which way is the “past” in this system. We can equally well say a collision at one time is “caused” by the positions of the balls one second in the “past” or one second in the “future”. There is no basis for choosing a direction of causality between two events.
In our universe, our time is microscopically reversible but macroscopically irreversible, because of the fact that the universe is proceeding from a low entropy state (we call that direction the “past”) to a high entropy state (the “future”). I am curious, can anyone coherently describe a universe with nothing similar to irreversible time, but with a useful notion of causation? Or with something like irreversible time, but no causation whatsoever? I have tried (for much more than five minutes!) and not succeeded , but I am still far from sure that it’s impossible to do. It might be too much to ask to imagine actually being in a universe without causation or time, but perhaps we can think of how such a universe could look from the outside.
I think that in a universe without a cause and effect structure, we’d tend to see more chaos than we do. Casual models would tend to fail to correspond to reality; all we could do is attempt to reason over joint probability distributions, which, as was explained, is kind of hopeless.
Well, my experiences could not be readily predicted by a simple Bayesian net. Thus I would expect the joint probability distribution on all things to be really complicated unless there were some other kind of pattern to it. Heck, maybe my experiences correspond to repeated independent samples from a giant multidimensional Gaussian or something (rotated of course so that the natural observable variables have non-trivial covariance).
I’m having a hard time making sense of the question. I’m sort of trying to imagine that there are no causal relations, and then opening my eyes to see what’s different. Except ‘seeing’ and ‘looking’ don’t make sense any more. What could it mean for something to ‘appear’? I can’t get a grip on even the idea of ‘experience’.
At which point I conclude that either I am not imaginative enough, or the exercise is inconceivable.
Can you coherently say how reality might look, if our universe did not have the kind of structure that appears in a causal model?
Assuming our universe is causal, then no you cannot. Any universe you can imagine has laws of physics which can be modelled by the interactions of the neurons in your brain, and are therefore causal.
There might be some things that can only be experienced in an acausal universe, but it is not possible for me to imagine them.
In a universe without causal structure, I would expect an intelligent agent that uses an internal causal model of the universe to never work.
Of course you can’t really have an intelligent agent with an internal causal model in a universe with no causal structure, so this might seem like a vacuous claim. But it still has the consequence that
P(intelligence is possible|causal universe)>P(intelligence|acausal universe).
If intelligence is seen as optimization power- in the sense of agents that constrain possible futures for their benefit- then it seems clear that the rewards to intelligence are 0 or negative in acausal universes, and so they should be less likely than in universes where they have positive rewards.
I suppose I would say that reality would look as if things happened with no observable pattern related to the things that happen before them, but looking at things requires a long causal chain between photons being emitted and signals in my brain. Supposing I happened to somehow flash into existence for an instant in a noncausal world, or that causality suddenly failed, I would not expect to be able to experience anything past that point since my experiences depend on so many causal processes.
An acausal world would be a world where there is experience (some kind of ‘reality’) but without the possibility of contradiction. It is like a dream, where what you experience is a story and that story can be written over, and can shift, at any moment, without contradiction. So at one moment you see a cup, and then the next moment, you didn’t see a cup. It’s not that the cup changed or that you were mistaken, it’s just that at first your experience was “seeing a cup” and then at the next moment your experience was, “I wasn’t there to see that cup”. The experiences both happened: You saw it. And you weren’t there and didn’t see it. It’s a string of happenings connected by the word ‘and’ : I saw a cup and I didn’t see a cup and I was there and I wasn’t hungry and the grape hurt.
This isn’t an original idea, I realize now. I’ve read of a place like this in at least a couple science fiction stories.
I would expect not exist in a way that suggests causality, e.i. being born and then expecting death, rather than the other way around. This is hard for me to imagine because I didn’t really evolve for that world. It’s possible that our universe doesn’t work that way at the smallest level, but it seems might suspicious that random events lead to a largest world that operates very deterministically. Still, it is possible that this is just the manifestation of probabilistic laws at the smallest level. It’s definitely paying rent so far,(for those who do the experiments) so that’s we’re going with, and there hasn’t been a good argument or experiment against it yet.
Infintesmal “violations” of causal laws as manifestations of probabilistic laws don’t seem to effect me very much. Large ones that would pay rent haven’t happened on the level that would pay rent on an evolutionary or personal level, and, as I understand it (which is not terribly well) these probably won’t happen unless the universe ran from the big bang to heat death a couple hundred times.
I can make models in my head where the universe (on my scale) is really chaotic, but looks deterministic because of a conspiracy by matrix gods or whatever, but that seems to violate Occam’s Razor, for what that’s worth when matrix gods control your life.
Koan 3:
Does the idea that everything is made of causes and effects meaningfully constrain experience? Can you coherently say how reality might look, if our universe did not have the kind of structure that appears in a causal model?
Physicists tell us that reality is, at the lower levels, described by differential equations. Those describing the temporal evolution of systems are generally hyperbolic differential equations. That is, they have microscopic causal structure: the properties at a point (x,t+dt) depend on the properties only in a small, finite neighbourhood of x at time t. This is what allows larger scale events to be described more abstractly in terms of causal graphs. (A known problem here is the time-symmetry of all these equations. I don’t have a solution to that either.)
Some have speculated about the very finest scale being discrete, with fundamental laws of temporal evolution such as those of cellular automata or graph rewriting. That would also provide the fundamental causal structure from which causal structure on the macroscopic level emerges.
A universe whose fundamental laws were all elliptic differential equations—those in which a change in boundary conditions in one place changes the solution everywhere at once—would not support causal reasoning. Everything depends on everything else and none of its emergent phenomena would be describable by sparse causal graphs. I’m not sure you could have agents within such a universe, for it to look like anything to them, or any notion of time, but we can imagine such universes from outside.
A causally disconnected event would not affect our experience, so no, it does not constrain our experience. But it wasn’t meant to: it was meant to constrain our maps, not our experience. To stop us from believing meaningless statements.
Every causally separated group of events would essentially be its own reality.
No. For any set of observations O1, O2, …, O_N, you can construct an overprecise causal model that links some central cause to nodes O1, O2, …, O_N. [That is, our causal model is: “You observed O1 because God willed it. Then you observed O2 because God willed it...”] Thus causal models can explain any set of observations. Constraining experience requires in addition some sort of Occam’s Razor that prefers simpler causal models.
I’d agree with the assertion “Unknowable relationships are equivalent to no relationship”. In other words, cause-and-effect is only meaningful if we have some ability to gather information as to the nature of the relationships. Occam’s Razor is one such method, but I wouldn’t assume that it’s specifically required—we could just as easily be born with divine insight as to the cause-effect relationships.
To answer this, I need to answer another question: What would the universe look like if it did not have the structure of causal models? If I know that then I can know whether or not that universe looks different than ours.
So we’re talking about a universe where there is no A --> B causal connections. Where you can’t accurately say something like “When I eat, it causes me to be less hungry,” or even say anything, since “saying” something requires some sort of causal ability: the ability to push air in intensional patterns.
And that universe… really doesn’t look like ours. I might want to talk about a universe where there are correlations but not causations, but then how do I explain the correlations? Are they just brute facts? That seems unlikely. But even in that event, I would expect rules to break down in chaotic ways: one day, food wouldn’t make me feel nourished. And it wouldn’t be because I ate the wrong foods or something like that, it’d just be because the correlation broke down. And that really doesn’t look like our universe either. I may be wet because it was raining, but I don’t get wet merely because some ‘correlation’ between ’sunny_day” and “not_wet” broke down.
Actually we aren’t. We are talking about an universe where there are effects that happen without cause. That doesn’t mean that effects that have causes aren’t allowed.
Hm. That is conceptually possible, I suppose. Although I can’t really imagine how that sort of demarcation criteria would work.
Yes, to a limited extent I think I can.
A universe without a completely causal structure would have to have a number of effects that have no cause. (This need not apply to all effects in this universe, merely to a subset of effects). The Steady-state universe, a now abandoned alternative to the Big-bang model, may be an example; in the steady-state universe, if I remember correctly, it was theorised that small bits of matter (hydrogen molecules) appeared out of nowhere at random times, at a very low rate. This is an example of an effect without a cause.
Alternatively; consider a universe where a man suddenly appears out of nowhere in the middle of a public area. He claims to be a time traveller, from fifty years in the future, coming back in time to prevent some terrible disaster. Though his story is unbelievable, the disaster he predicts is prevented. Fifty years pass, and the time traveller is not sent back to the past (since the disaster was, after all, prevented). This does not cause a paradox (the laws of this universe are that matter can appear at any time, in any arrangement, including a person with false memories of time time travel from a non-existant future) Such a potential universe thus has an effect (the man appears) without a cause.
The examples don’t quite work. In that steady-state universe, the appearing matter subsequently interacts and so is causally connected to the rest of the universe. You just have to trace the connections backwards, and eventually you reach a stopping point. Similarly with the false time traveler: he causally affected the world, so he’s clearly part of a chain of causes and effects.
It’s a separate question to ask whether everything has a causal in-connection and a causal out-connection. Both your examples, and epiphenomal theories of mind, are meaningfully about unidirectional causal links.
Hmmm. I had been trying to consider the case where some events have no causes. Now, you’re pointing out—as I understand your argument, and please correct me if I am wrong—that the same event can be a cause, and therefore that it is a part of an interconnected causal universe.
This is an interesting argument. If I notice the existance of something, then that is a causal relationship; it exists, and this causes me to notice it by some means. Therefore, anything that I observe shares a causal relationship with the fact of its observation; if that is enough to consider it part of a causal universe, then I can only observe a causal universe. I cannot imagine anything that I cannot, by definition, observe in any manner (including by any deduction) constraining my experience.
On the other hand, I can (at least in certain imagined universes) observe effects without causes; I can observe the time traveller appearing for absolutely no reason.
I had assumed the question was “a universe where an event can have out-connection but not in-connection” (and the consciousness one was about having an in-connection but no out-connection).
In a universe with NO connections, you wouldn’t get patterns, much less emergent patterns—no atoms, no stars, no planets, no life, not even internet!
Multiple segregated causal networks would be multiple realities (I think the simplest reference would be to think about two different books or virtual worlds, although there’s actually still some connection there)
Individual events which have out-connections but not in-connections, by contrast, seems like a fairly interesting question to explore. Why DO we assume that all evens have in-connections? Why not just assume the weather is because Zeus is mad, and Zeus’ emotions are beyond the ken of mortal minds?
Not all, the past doesn’t have in-connections and the future doesn’t have out-connections.
Can you explain what you mean by that? I tend to model past events as having even-further-past causes. I definitely model future events as having even-farther-future ramifications. So they’d seem to generally have both in and out.
I was referring to the past (or future) as a whole.
At first thought. It seems that if it could be falsified, then it would fail the criteria of containing all and only those hypotheses which could in principle be falsified. Kind of like a meta-reference problem; if it does constrain experience, then there are hypotheses which are not interpretable as causal graphs that constrain experience (no matter how unlikely). This is so because the sentence says “all and only those hypothesis that can be interpreted as causal graphs are falsifiable”, and for it to be falsified, means verifying that there is at least one hypothesis which cannot be interpreted as a causal graph which is falsifiable. Short answer, not if we got it right this time.
(term clarification) All and only hypotheses that constrain experience are falsifiable and verifiable, for there exists a portion of experience space which if observed falsifies them, and the rest verifies them (probabilistically).
Asserting that a particular causal model is an accurate description of the universe certainly constrains experience to fit the causal model. Asserting that it is possible to accurately describe the universe with a causal model is tautologically true because a fully connected model fits every possible probability distribution. Asserting that it is possible to accurately describe the universe with a simple causal structure constrains experience to match a simple causal model. If you know that the universe fundamentally works by running some causal model, asserting that the universe runs this particular causal model predicts that you will never find a more accurate causal model for describing the universe. I’m not sure how asserting that the universe fundamentally works by running some causal model would constrain experience.
Several possible examples come to mind for a universe with no cause or effect.
First is a universe with only one thing in it, so that there’s nothing for it to be causally connected to.
Second is a universe with multiple things in it that could in principle interact but due to the set-up of the universe never actually do interact. For example, a universe of rigid particles in a void where they would interact if they struck, but the distances between all particles are too great for that to occur in the lifetime of the particles.
Third, a universe in which its entities do interact, but nothing ever changes, so there are no nontrivial correlations. Perhaps count a universe of mutually repelling particles in a void, arranged in an unchanging crystalline structure.
Fourth, more loosely, is a universe in which its entities do interact and change, but the arrangement of all the things is such that only minimal correlations arise. Perhaps a universe analogous to a closed system containing a gas at thermodynamic equilibrium.
Prescinding from those, the idea that everything in our universe is made of causes and effects constrains my expectations in that there should multiple things (check) that actually interact (check) and change (check) and have nontrivial correlations (check). Other than the continuation of such things, I can’t readily think of any sense in which the idea constrains my expectations for future experiences.
To clarify you are pointing out that without cause and effect, stars would not even form, or even baryons for that matter. A gas at thermodynamic equilibrium probably would not be conscious, so from there we can go straight for the Anthropic Principle. Otherwise the question has no real solution—like asking what a peacock would look like if eyes didn’t exist. (Handoflixue already killed this horse, though—sorry for beating it.)
Any time a theory of cosmology implies that you’re a Boltzmann brain, run. ;)
My first answer is that the idea of ‘interventions’ comes from causality- if I don’t like being wet, and it’s raining, I can deploy an umbrella, and that will make me not get wet(ter) from the rain. The idea that everything is made of causes and effects meaningfully constrains actions, because an agent that understands causes can manipulate reality better than an agent which doesn’t understand causes.
But that’s just a further elaboration of what reality looks like now. It’s difficult for me to imagine a world without causality- and I don’t think that’s just because I (like most humans) am a deeply causal thinker. Causal models are just math, and so they can be imagined just like multiple spatial geometries can be imagined, regardless of what the universe’s real shape is. I think you would need to have a universe in which no causal models could be justified by the data, which would be an incredibly strange place.
And, actually, by the definition of universe you use in the post, a universe without a causal structure would just be a single node, forever alone.
If our universe did not have the kind of structure that appears in a causal model, then our reasoning would not function properly. Induction would fall completely flat, and I don’t think our brains would work right. We probably wouldn’t exist in such a world, but if we’re taking into account anthropic effects… well, I’m not even sure a human could survive long enough for a single conscious thought, since their state at time t+1 wouldn’t follow from their state at time t.
After skimming others’ replies, I’ve realised that I’ve answered a different question. To answer this one: no, but we’ve got no way of reasoning about or utilising anything else, so it doesn’t matter. That there are no uncaused causes of real things (a weaker claim) does meaningfully constrain experience, though.
If the universe were not governed by cause and effect, then we could not consistently improve our predictions of the future by observing the past, even by a little bit.
No. I literally assign prior probability zero to the statement that the universe is not made out of causes and effects, because there is causal structure in Turing machines and in all Turing-complete models of computation which could make up the Solomonoff prior. Causal structure is a very broad thing—it’s just a sparse graph of interacting entities with a lattice ordering.
I can imagine a universe in which the local ordering I observe doesn’t go as far forward or back as I thought, and the true everything-is-causes-and-effects structure is pushed one layer back to something completely hidden from me. I can imagine a universe in which I’ve falsely inferred an ordering which isn’t there, and getting confused by cycles in a graph that I thought was causal. But a universe with no causality at the lowest layer—I think causality is inherent in too many things, and that after subtracting those things there’s not enough option space left to make a universe out of.
I think this is one of the few instances where p(0) is actually appropriate! :)
If you can’t imagine an universe that’s not made out of causes and effects than talking about such an universe is meaningless.
To be able to assign a probability zero to the statement that the universe is not made out of causes and effects you have to be able to imagine a universe that’s not made out of causes and effects.
Meaningless statements can’t be true or false. Speaking about their probability makes no sense.
Before Einstein nobody could imagine without universal time either.
In other words, if you can’t imagine a universe with property X, that’s a fact about you not about the universe.
In other words, causality is the invisible pink unicorn.
I don’t understand this reply at all, except as an indication that I didn’t communicate these concepts as well as I’d hoped.
The text I quoted in the grandparent seems to be saying that even if the universe doesn’t contain causality, we can always postulate an external causality structure even if most of it can’t be observed.
How about mild violations of causality?
That isn’t a violation of causality, it’s just a universe with time that goes infinitely far forward and back.
Time appears to stretch backward infinitely, because local causality still looks nice. But actually it only stretches backward to now. If time was actually a straight line rather than a cycle, then one could intervene in this system and it would only change the future. But if you intervened in a cyclic system, you would find that you had changed what looks like the past.
In fact, self-consistency constraints would kick in and logically prevent you from some sorts of intervention that would make perfect sense if time stretched off to infinity—it’s like using quantum mechanics instead of classical mechanics, where classically it seems like you should be able to have any amount of energy you want.
More philosophically, we’ve run into Aristotle’s distinction between self-cause and infinite regress. And also why Bayesian networks are typically defined as directed acyclic graphs, thus putting cyclic graphs outside of the hypothesis-space.
I think I understand your distinction between infinite regress and cyclical causation, but I don’t understand why that implies a cyclical universe violates causality. To rephrase jimrandomh: that isn’t a violation of causality, it’s just a universe with cyclical time.
Well, one can still think of it causally—you can still draw a graph with arrows, at least. But it’s atypical causality.
Typical causality is like kicking a ball. The ball sits still until you kick it, and you can kick it however you like and it will roll away. But once you have loops, it’s like if the ball had to go through a portal to the past and kick itself. As soon as you try to kick the ball, the ball you would have kicked has already gone back to the past and hit itself in a way consistent with the motion of your foot, so it will feel quite unlike kicking the first ball. And in fact it is physically impossible to move your foot in a way inconsistent with the ball being the cause of its own motion, even though trying to kick the ball restricts the possibilities—or rather, being able to try to kick the ball tells you that the possibilities were already restricted...
In typical causality, the ball has a reason for moving the way it does—you can trace the motion backwards to some acceptable starting point, like “I kicked it as hard as I could toward the fence.” When you add cycles, tracing the chain of arrows back does not need to end at anything you find remotely satisfactory or even unique—“the ball moved because it hit itself because it moved because it hit itself...”
This is a problem with your personal intuitions as a medium-sized multicellular century-lived mammalian tetrapod. No event in this chain is left uncaused, and there are no causes which lack effects in this model. Causality is satisfied. If you are not, that’s your problem. Hell, the energy is even conserved. It runs in a spatial as well as a temporal circle, what with the ball hitting itself and skidding to a stop exactly where it was sitting to wait for the next hit. On the other hand, in such a universe quantum mechanics does not apply, because worldlines cannot split, which also removes any possibility of entropy. ALL interactions are 100% efficient.
Does EY give his own answer to this elsewhere?
Try to guess what he would say before reading it. You can also click on one of the tags above to read, say, the sequence on epistemology.
Meditation 3: [Hardest of the meditations, for me.] Let us observe the difference between [post-utopian]-->[colonial alienation] and a connected thing (say [I see you picked Ace]-->[You see you picked Ace] from a deck of cards): In the first case, there is no way to settle an argument about whether Ellie is post-utopian or not. We would predict that it would cause arguments between people that are not settled. Anything connected to the causal web is more likely to lead to settlable arguments, at least among people behaving more-or-less rationally. It is not a perfect test, but it does suggest that I expect to see different things from connected networks and unconnected networks, like people changing their minds.
There are three alternatives I can think of:
1) The universe has a joint probability distribution such that events are not independent, but so few events are independent that limiting the description to a causal one does not materially reduce the complexity of the “true” model. In this case, There would only be the joint look-up table.
2) All events are independent.
3) The universe is not well-described by the laws of probability.
The first case would make prediction pretty much impossible (since you’re never dealing with the exact same set of variables twice). “Same river” and all that. No prediction more specific than “the universe persists in some way” would be true very often on average, since there are so many possible outcomes, and no reason to believe that the next joint probability for the event you care about is similar to the last one.
In the second, you could predict roughly the proportion of events based on the proportion of past events, but there would be no discernible pattern, or result of action.
In the third, I can’t tell you what you’re likely to observe, for obvious reasons.
It would be completely random, with all events being equally likely at every point in time. It would have no history, since the past has no effect on the present or future
You could plug a baby’s nervous system into the output of a radium decay random number generator. It’d probably disagree (disregarding how crazy it would be) that its observations were best described by causal graphs.
I think it is a mistake to tie the question of what reality is to the particulars of the physics of our actual universe. These questions are about what it is to have an external reality, and the answers to them should be the same whether the question is asked by us in our current universe, or by some other hapless inhabitants of a universe bearing a distinct resemblance to Minecraft.
I can imagine types of existence which don’t include cause and effect—geometrical patterns are an example—there are relationships, but they are not cause and effect relationships—they are purely spatial relations. I can imagine living in a universe where part of its structure was purely such spatial relationships, and not a matter of cause and effect.
Imagine a universe that is made only of ideal billiard balls eternally bouncing around on a frictionless, pocketless billiard table. Essentially the same thing as selylindi’s idea of a gas in thermodynamic equilibrium. Imagine yourself observing this universe as a timeless observer, or to aid the imagination, that it’s “time” dimension is correlated to our space dimension, so we see the system as an infinite frozen solid, 11 by 6 by infinity, with the balls represented by solid streaks inside that go in straight lines except where they bounce off each other or the boundary of the solid.
Now, this system internally has a timelike dimension, except without increasing or decreasing entropy. And the physics of the system are completely reversible, so we have no basis of saying which way is the “future” and which way is the “past” in this system. We can equally well say a collision at one time is “caused” by the positions of the balls one second in the “past” or one second in the “future”. There is no basis for choosing a direction of causality between two events.
In our universe, our time is microscopically reversible but macroscopically irreversible, because of the fact that the universe is proceeding from a low entropy state (we call that direction the “past”) to a high entropy state (the “future”). I am curious, can anyone coherently describe a universe with nothing similar to irreversible time, but with a useful notion of causation? Or with something like irreversible time, but no causation whatsoever? I have tried (for much more than five minutes!) and not succeeded , but I am still far from sure that it’s impossible to do. It might be too much to ask to imagine actually being in a universe without causation or time, but perhaps we can think of how such a universe could look from the outside.
What is the difference between constraining experience and constraining expectations? Is there one?
I think that in a universe without a cause and effect structure, we’d tend to see more chaos than we do. Casual models would tend to fail to correspond to reality; all we could do is attempt to reason over joint probability distributions, which, as was explained, is kind of hopeless.
Well, my experiences could not be readily predicted by a simple Bayesian net. Thus I would expect the joint probability distribution on all things to be really complicated unless there were some other kind of pattern to it. Heck, maybe my experiences correspond to repeated independent samples from a giant multidimensional Gaussian or something (rotated of course so that the natural observable variables have non-trivial covariance).
I’m having a hard time making sense of the question. I’m sort of trying to imagine that there are no causal relations, and then opening my eyes to see what’s different. Except ‘seeing’ and ‘looking’ don’t make sense any more. What could it mean for something to ‘appear’? I can’t get a grip on even the idea of ‘experience’.
At which point I conclude that either I am not imaginative enough, or the exercise is inconceivable.
(Written before reading other comments.)
Assuming our universe is causal, then no you cannot. Any universe you can imagine has laws of physics which can be modelled by the interactions of the neurons in your brain, and are therefore causal.
There might be some things that can only be experienced in an acausal universe, but it is not possible for me to imagine them.
In a universe without causal structure, I would expect an intelligent agent that uses an internal causal model of the universe to never work.
Of course you can’t really have an intelligent agent with an internal causal model in a universe with no causal structure, so this might seem like a vacuous claim. But it still has the consequence that
P(intelligence is possible|causal universe)>P(intelligence|acausal universe).
That seems plausible but I must admit that I don’t know enough details about possible “acausal universes” to be particularly confident.
If intelligence is seen as optimization power- in the sense of agents that constrain possible futures for their benefit- then it seems clear that the rewards to intelligence are 0 or negative in acausal universes, and so they should be less likely than in universes where they have positive rewards.
This one is great—it really does have the contradictory nature of traditional koans.
Just try to picture what you would do to test whether the universe was causal, and how we would adjust our models based on such a test.
I suppose I would say that reality would look as if things happened with no observable pattern related to the things that happen before them, but looking at things requires a long causal chain between photons being emitted and signals in my brain. Supposing I happened to somehow flash into existence for an instant in a noncausal world, or that causality suddenly failed, I would not expect to be able to experience anything past that point since my experiences depend on so many causal processes.
An acausal world would be a world where there is experience (some kind of ‘reality’) but without the possibility of contradiction. It is like a dream, where what you experience is a story and that story can be written over, and can shift, at any moment, without contradiction. So at one moment you see a cup, and then the next moment, you didn’t see a cup. It’s not that the cup changed or that you were mistaken, it’s just that at first your experience was “seeing a cup” and then at the next moment your experience was, “I wasn’t there to see that cup”. The experiences both happened: You saw it. And you weren’t there and didn’t see it. It’s a string of happenings connected by the word ‘and’ : I saw a cup and I didn’t see a cup and I was there and I wasn’t hungry and the grape hurt.
This isn’t an original idea, I realize now. I’ve read of a place like this in at least a couple science fiction stories.
I would expect not exist in a way that suggests causality, e.i. being born and then expecting death, rather than the other way around. This is hard for me to imagine because I didn’t really evolve for that world. It’s possible that our universe doesn’t work that way at the smallest level, but it seems might suspicious that random events lead to a largest world that operates very deterministically. Still, it is possible that this is just the manifestation of probabilistic laws at the smallest level. It’s definitely paying rent so far,(for those who do the experiments) so that’s we’re going with, and there hasn’t been a good argument or experiment against it yet.
Infintesmal “violations” of causal laws as manifestations of probabilistic laws don’t seem to effect me very much. Large ones that would pay rent haven’t happened on the level that would pay rent on an evolutionary or personal level, and, as I understand it (which is not terribly well) these probably won’t happen unless the universe ran from the big bang to heat death a couple hundred times.
I can make models in my head where the universe (on my scale) is really chaotic, but looks deterministic because of a conspiracy by matrix gods or whatever, but that seems to violate Occam’s Razor, for what that’s worth when matrix gods control your life.