It seems rather obvious to me that there are no “Platonic” laws of physics, and there is no Platonic math existing in some ideal realm.
I am rather uncertain about what it means for something to “exist”, as a stand-alone form. When people use this word, it often seems to end up referring to a free-floating belief that does not pay rent in anticipated experiences.
Is there anything different about the world that I should expect to observe depending on whether Platonic math “exists” in some ideal realm? If not, why would I care about this topic once I have already dissolved my confusion about what beliefs are meant to refer to? What could serve as evidence one way or another when answering the question of whether math “exists”?
By contrast, we can talk about “reality” existing separately from our internal conception of it because the map is not the territory, which has specific observable consequences, as Eliezer beautifully explained in a still-underrated post from 17 years ago:
I pause. “Well . . .” I say slowly. “Frankly, I’m not entirely sure myself where this ‘reality’ business comes from. I can’t create my own reality in the lab, so I must not understand it yet. But occasionally I believe strongly that something is going to happen, and then something else happens instead. I need a name for whatever-it-is that determines my experimental results, so I call it ‘reality’. This ‘reality’ is somehow separate from even my very best hypotheses. Even when I have a simple hypothesis, strongly supported by all the evidence I know, sometimes I’m still surprised. So I need different names for the thingies that determine my predictions and the thingy that determines my experimental results. I call the former thingies ‘belief,’ and the latter thingy ‘reality.’ ”—The Simple Truth
(Bolding mine) If the bolded section was not correct, i.e., if you were an omniscient being whose predictions always panned out in actuality, you would likely not need to keep track of reality as a separate concept from the inner workings of your mind, because… reality would be the same as the inner workings of your mind. But because this is false, and all of us are bounded, imperfect, embedded beings without the ability to fully understand what is around us, we need to distinguish between “what we think will happen” and “what actually happens.”
Later on in the thread, you talked about “laws of physics” as abstractions written in textbooks, made so they can be understandable to human minds. But, as a terminological matter, I think it is better to think of the laws of physics as the rules that determine how the territory functions, i.e., the structured, inescapable patterns guiding how our observations come about, as opposed to the inner structure of our imperfect maps that generate our beliefs.
From this perspective, Newton’s 3rd law, for example, is not a real “law” of physics, for we know it can be broken (it does not perfectly represent the underlying reality). Neither is General Relativity or QFT, partly because we know they are at odds with one another in particular regimes and do not always give predictions that align with our observations. The “laws” of physics would be restricted to the collection of rules that always output correct predictions (which might very well be an empty set if, for example, reductionism ends up being false and we turn out to live in a world devoid of perfect underlying structure).
Is there anything different about the orld that I should expect to observe depending on whether Platonic math “exists” in some ideal realm? If not, why would I care about this topic once I have already dissolved my confusion about what beliefs are meant to refer to?
Word of Yud is that beliefs aren’t just about predicting experience. While he wrote Beliefs Must Pay Rent, he also wrote No Logical Positivist I.
(Another thing that has been going on for years is people quoting VBeliefs Must Pay Rent as though it’s the whole story).
Maybe you are a logical positivist, though....you’re allowed to be , and the rest of us are allowed not to be. It’s a value judgement: what doesn’t have instrumental value toward predicting experience can still.have terminal value.
If you are not an LP,.idealist, etc, you are interested in finding the best explanation for.your observations—that’s metaphysics. Shminux seems.sure that certain negative metaphysical claims are true—there are No Platonic numbers, objective laws,.nor real probabilities. LP. does not allow such conclusions: it rejects both positive and negative metaphysical claim as meaningless.
The question is what would support the dogmatic version of nomic antirealism, as.opposed to the much more defensible claim that we don’t know one way or the other (irrealism)
Later on in the thread, you talked about “laws of physics” as abstractions written in textbooks, made so they can be understandable to human minds. But, as a terminological matter, I think it is better to think of the laws of physics as the rules that determine how the territory functions, i.e., the structured, inescapable patterns guiding how our observations come about, as opposed to the inner structure of our imperfect maps that generate our beliefs.
The term can be used in either sense. Importantly, it can be used in both senses: the existence of in-the-mind sense doesn’t preclude the existence of the in—reality sense. Maps dont necessarily correspond to reality, but they can. “Doesn’t necessarily correspond ” doesnt mean the same thing as necessarily doesn’t correspond”.
@Shminux
It is not clear whether any randomly generated world would necessarily get emergent patterns like that, but the one we live in does, at least to a degree
And maybe there is a.reason for that...and maybe the reason is the existence of Platonic in -the-territory physical laws. So there .s an argument for nomic realism. Is there an argument against? You haven’t given one, just “articulated a claim”.
So in your opinion, there is no reason why anything happens?
There is an emergent reason, one that lives in the minds of the agents.
But that’s not the kind of reason that makes anything happen—it’s just a passive model.
The universe just is.
That isn’t an argument against or for Platonic laws. Maybe it just is in a way that includes Platonic laws, maybe it isn’t.
In other words, if you are a hypothetical Laplace’s demon, you don’t need the notion of a reason, you see it all at once, past, present and future.
I think you mean a hypothetical God with a 4D view of spacetime. And LD only has the ability to work out the future from a 3D snapshot. Yes, if you could see past present , you wouldn’t need in-the-mind laws to.make predictions..but, again that says nothing about in-the-territory, Platonic laws. Even if God doesn’t need in-the-mind laws, it’s still possible that reality needs in-the-territory laws to make things happen.
“a causal or explanatory factor” is also inside the mind
Anthropics and Boltzmann brains are also in the mind. As concepts.
What’s in the mind has to make sense, to fit together. Even if maths is all in the mind, maths problems still need to be solved. Saying maths is all in the mind does not tell you whether a particular theorem is true or false. Likewise , saying metaphysics is all in the mind does bot tell you that nomic realism is false, and anthropics true.
We have a meta map of the mind world relation, and if we assume a causal relation from the world to the mind, we can explain where new information comes from, and if we assume lawful behaviour in the world, we can explain regularities. Maybe these are all concepts we have, but we still need to fit them.together in a way that reduces the overall mystery, just as we still need to solve maths problems.
What do you mean by an “actual explanation”?
Fitting them.together in a way that reduces the overall mystery.
We live in it and are trying to make sense of it
And if you want us to believe that the instrumentalist picture makes the most sense, you need to argue for it. The case for realism.l, by contrast, has been made.
A more coherent question would be “why is the world partially lossily compressible from the inside”, and I don’t know a non-anthropic answer
The objective existence of physical laws, nomic realism, is a non anthropic answer which has already been put to you.
ETA
Maybe, again, we differ where they live, in the world as basic entities or in the mind as our model of making sense of the world.
...or both, since...
it is foolish to reduce potential avenues of exploration.
Yudowsky’s argument that probability is subjective is flawed, because it rests on assumption that the existence of subjective probability implies the non existence of objective probabilty but the assumption is never justified. But you seem to buy into it anyway. And you seem to be basing your anti realism o n a similar unargued assumption.
you are interested in finding the best explanation for.your observations—that’s metaphysics. Shminux seems.sure that certain negative metaphysical claims are true—there are No Platonic numbers, objective laws,.nor real probabilities
I really don’t understand what “best explanation”, “true”, or “exist” mean, as stand-alone words divorced from predictions about observations we might ultimately make about them.
This isn’t just a semantic point, I think. If there are no observations we can make that ultimately reflect whether something exists in this (seems to me to be) free-floating sense, I don’t understand what it can mean to have evidence for or against such a proposition. So I don’t understand how I am even supposed to ever justifiably change my mind on this topic, even if I were to accept it as something worth discussing on the object-level.
A: “I am interested in knowing whether Platonic mathematical entities exist.”
B: “What does it mean for something to ‘exist’?”
A: “Well, it seems to be an irreducible metaphysical claim; something can exist, or not exist.”
B: “Um… I’m not sure about this whole notion of ‘metaphysics’. But anyway, trying a different track, do these Platonic mathematical entities interact with observable physical reality in any discernible way?”
A: “I mean, as a practical descriptor, we use those particular mathematical entities because they are useful to us when we model reality; but at their core, they are supposed to be Platonic. They are forms, not concrete entities. Nevertheless, we can reason about them; we can define them, relate them to one another, prove theorems about them. We can even develop better intuitions about them over time as we work with them more and more. Is that what do you mean by ‘discernible’?”
“Information theory 101,” the boy said in a lecturing tone. “Observing variable X conveys information about variable Y, if and only if the possible values of X have different probabilities given different states of Y.
B (continuing): “So let’s think of the existence/non-existence status of Platonic math as the variable Y. Now, look, I am fine with accepting a broad perspective on the ‘variable’ X. Let it be an ocular observation, or the running of a scientific experiment, or a bunch of internal reasoning, or other stuff you might propose. I just want to know whether, given that these Platonic entities seem to live in an entirely separate magisterium, how is it that any observation/thought/conclusion we reach about the supposed existence of Platonic math (i.e., any particular value of Y) can result in different probabilities for the possible values of X?”
A: “You’re implicitly adopting a strong Bayesian perspective that you have neither argued for nor properly applied-”
B: “Fine! Drop the explicit probability stuff, then. I exist as a being embedded in the physical world. These mathematical entities are defined to exist (if they exist, which seems to be the question) in a Platonic realm that does not intersect this reality. After all, they are ideal forms, not concrete instances. So where is the entanglement between the two realms?”
A: “What do you mean by entanglement? I hope you’re not sneakily trying to assume a correspondence theory of truth yet again without justifying it.”
B: “What I mean is that I don’t understand how anything I do in this physical world that I belong to-”
A: “What makes you so sure you really live in a physical world? That’s the territory, not the map. All you have access to is the information given by your sense data and by your internal state of mind, including your memory. Maybe there is no outside world after all; maybe solipsism is true; maybe you live in an infinite-layer-deep simulation. Or maybe all of that is wrong and you actually are correct about living in some universe that runs on rough modifications of General Relativity and QFT, but even in that case, at the present moment you are totally not justified in assigning such confidence to this. You are merely assuming it instead, and this is precisely the type of metaphysical assumption you were pretending to be unable to wrap your head around at the start of the conversation.”
B: “Good Lord, fine! I’ll drop the physical universe assumption as well, for purposes of this conversation, even though I think I actually do have great justifications for being confident in it. But I won’t let the discussion get derailed any further in that direction. But I can still say that I am a concrete entity, precisely the type of being that shminux was contrasting the nature of when they mentioned Platonic mathematics. So I am concrete, and everything that goes on in my brain runs on the concrete me-stuff (I am intentionally avoiding the word ‘matter’), and yet I am supposed to have an opinion about the existence/non-existence of something that is entirely not concrete.”
A: “Isn’t that something you already conceded you were willing to try to do when you entered this dialogue? You could have walked away at the beginning or anytime after giving your whole spiel about beliefs paying rent in anticipated experiences.”
B: “Yes, I am willing to try to do that. But I don’t understand how I am supposed to ever change my mind on this topic, as I have already mentioned. What can possibly sway me one way or another when all variables X that I appear to be able to observe (or think about, etc.) are in the concrete realm, which is defined to be entirely non-intersecting with the Platonic realm? Does anything in this concrete realm have different values, or likelihoods, or entanglements, given different possible versions of whether the Platonic realm and its inhabitants exist? If math exists, is there anything that distinguishes this possibility? If math doesn’t exist, is there anything that distinguishes that possibility? What can count as epistemically justifiable updating (or, if you dislike the Bayesian connotations around that word, think ‘mind-changing’ instead) on this topic? As a general matter, I usually change my mind if I see new evidence or hear new good arguments, but I think of ‘good arguments’ as lines of logic and reasoning, whose validity and soundness implies we are more likely to be in a world where certain possibilities are true rather than others (when mulling over multiple hypotheses). What can that possibly mean in this context?”
A: [I’m not sure I can simulate A’s perspective after this point]
I really don’t understand what “best explanation”, “true”, or “exist” mean, as stand-alone words divorced from predictions about observations we might ultimately make about them.
Nobody is saying that anything has to be divorced from prediction , in the sense that emperical evidence is ignored: the realist claim is that empirical evidence should be supplemented by other epistemic considerations.
Best explanation:-
I already pointed out that EY is not an instrumentalist. For instance, he supports the MWI over the CI, although they make identical predictions. Why does he do that? For reasons of explanatory simplicity , consilience with the rest of physics, etc
.as he says. That gives you a clue as to what “best explanation” is. (Your bafflement is baffling...it sometimes sounds like you have read the sequences, it sometimes sounds like you haven’t. Of course abduction, parsimony, etc are widely discussed in the mainstream literature as well ).
True:- mental concept corresponds to reality.
Exists:- You can take yourself as existing , and you can regard other putative entieties as existing if they gave some ability to causally interact with you. That’s another baffling one, because you actually use something like that definition in your argument against mathematical realism below.
This isn’t just a semantic point, I think. If there are no observations we can make that ultimately reflect whether something exists in this (seems to me to be) free-floating sense, I don’t understand what it can mean to have evidence for or against such a proposition.
Empirical evidence doesn’t exhaust justification. But you kind of know that, because you mention “good argument” below.
So I don’t understand how I am even supposed to ever justifiably change my mind on this topic, even if I were to accept it as something worth discussing on the object-level.
Apriori necessary truths can be novel and surprising to an agent, in practice, even though they are apriori and necessary in principle… because a realistic agent can’t instantaneously and perfectly correlate their mental contents, and don’t have an oracular list of every theory in their head. You are not a perfect Bayesian. You can notice a contradiction that you haven’t noticed before. You can be informed of a simpler explanation that you hadn’t formulated yourself.
What can possibly sway me one way or another when all variables X that I appear to be able to observe (or think about, etc.) are in the concrete realm, which is defined to be entirely non-intersecting with the Platonic realm?
Huh? I was debating nomic realism. Mathematical realism is another thing. Objectively existing natural laws obviously intersect with concrete observations , because if Gravity worked on an inverse cube law (etc), everything looked very different.
You don’t have to buy into realism about all things, or anti realism about all things. You can pick and choose. I don’t personally believe in Platonic realism about mathematics, for the same reasons you don’t. I believe Nomic realism is another question...its logically possible for physical laws to have been different.
@shminux defined the the thing he is arguing against as “Platonic” .. I don’t have to completely agree with that, nor do you. Maybe it’s just a mistake to think of nomic realism as Platonism. Platonism marries the idea of non-mental existence and the idea of non causality...But they can be treated separately.
What can that possibly mean in this context?”
what context? You’re talking about mathematical realism, I’m talking about nomic realism.
as lines of logic and reasoning, whose validity and soundness implies we are more likely to be in a world where certain possibilities are true rather than others (when mulling over multiple hypotheses
What have I said that makes you think I have departed from that?
@Shminux
If push comes to shove, I would even dispute that “real” is a useful category once we start examining deep ontological claims
Useful for what? If you terminally value uncovering the true nature of reality, as most scientists and philosophers do, you can hardly manage without some concept of “real”. If you only value making predictions, perhaps you don’t need the concept....But then the instrumentalist/realist divide is a difference in values, as I previously said, not a case of one side being wrong and the other side being right.
“Exist” is another emergent concept that is not even close to being binary, but more of a multidimensional spectrum (numbers, fairies and historical figures lie on some of the axes).
“Not a binary” is a different take from “not useful”.
The critical point is that we have no direct access to the underlying reality, so we, as tiny embedded agents, are stuck dealing with the models regardless.
“No direct access to reality” is a different claim to “no access to reality” is a different claim to “there is no reality” is a different to “the concept of reality is not useful”.l
I can provisionally accept that there is something like a universe that “exists”, but, as I said many years ago in another thread, I am much more comfortable with the ontology where it is models all thea way down (and up and sideways and every which way).
It’s incoherent. What are these models, models of?
Thanks, I think you are doing a much better job voicing my objections than I would.
If push comes to shove, I would even dispute that “real” is a useful category once we start examining deep ontological claims. “Exist” is another emergent concept that is not even close to being binary, but more of a multidimensional spectrum (numbers, fairies and historical figures lie on some of the axes). I can provisionally accept that there is something like a universe that “exists”, but, as I said many years ago in another thread, I am much more comfortable with the ontology where it is models all the way down (and up and sideways and every which way). This is not really a critical point though. The critical point is that we have no direct access to the underlying reality, so we, as tiny embedded agents, are stuck dealing with the models regardless.
Thank you for your thoughtful and insightful reply! I think there is a lot more discussion that could be had on this topic, and we are not very far apart, but this is supposed to be a “shortform” thread.
I never liked The Simple Truth post, actually. I sided with Mark, the instrumentalist, whom Eliezer turned into what I termed back then as “instrawmantalist”. Though I am happy with the part
“Necessary?” says Inspector Darwin, sounding puzzled. “It just happened. . . I don’t quite understand your question.”
Rather recently Devs the show, which, for all its flaws, has a bunch of underrated philosophical highlights, had an episode with a somewhat similar storyline.
I am rather uncertain about what it means for something to “exist”, as a stand-alone form. When people use this word, it often seems to end up referring to a free-floating belief that does not pay rent in anticipated experiences.
Is there anything different about the world that I should expect to observe depending on whether Platonic math “exists” in some ideal realm? If not, why would I care about this topic once I have already dissolved my confusion about what beliefs are meant to refer to? What could serve as evidence one way or another when answering the question of whether math “exists”?
By contrast, we can talk about “reality” existing separately from our internal conception of it because the map is not the territory, which has specific observable consequences, as Eliezer beautifully explained in a still-underrated post from 17 years ago:
(Bolding mine) If the bolded section was not correct, i.e., if you were an omniscient being whose predictions always panned out in actuality, you would likely not need to keep track of reality as a separate concept from the inner workings of your mind, because… reality would be the same as the inner workings of your mind. But because this is false, and all of us are bounded, imperfect, embedded beings without the ability to fully understand what is around us, we need to distinguish between “what we think will happen” and “what actually happens.”
Later on in the thread, you talked about “laws of physics” as abstractions written in textbooks, made so they can be understandable to human minds. But, as a terminological matter, I think it is better to think of the laws of physics as the rules that determine how the territory functions, i.e., the structured, inescapable patterns guiding how our observations come about, as opposed to the inner structure of our imperfect maps that generate our beliefs.
From this perspective, Newton’s 3rd law, for example, is not a real “law” of physics, for we know it can be broken (it does not perfectly represent the underlying reality). Neither is General Relativity or QFT, partly because we know they are at odds with one another in particular regimes and do not always give predictions that align with our observations. The “laws” of physics would be restricted to the collection of rules that always output correct predictions (which might very well be an empty set if, for example, reductionism ends up being false and we turn out to live in a world devoid of perfect underlying structure).
Word of Yud is that beliefs aren’t just about predicting experience. While he wrote Beliefs Must Pay Rent, he also wrote No Logical Positivist I.
(Another thing that has been going on for years is people quoting VBeliefs Must Pay Rent as though it’s the whole story).
Maybe you are a logical positivist, though....you’re allowed to be , and the rest of us are allowed not to be. It’s a value judgement: what doesn’t have instrumental value toward predicting experience can still.have terminal value.
If you are not an LP,.idealist, etc, you are interested in finding the best explanation for.your observations—that’s metaphysics. Shminux seems.sure that certain negative metaphysical claims are true—there are No Platonic numbers, objective laws,.nor real probabilities. LP. does not allow such conclusions: it rejects both positive and negative metaphysical claim as meaningless.
The question is what would support the dogmatic version of nomic antirealism, as.opposed to the much more defensible claim that we don’t know one way or the other (irrealism)
The term can be used in either sense. Importantly, it can be used in both senses: the existence of in-the-mind sense doesn’t preclude the existence of the in—reality sense. Maps dont necessarily correspond to reality, but they can. “Doesn’t necessarily correspond ” doesnt mean the same thing as necessarily doesn’t correspond”.
@Shminux
And maybe there is a.reason for that...and maybe the reason is the existence of Platonic in -the-territory physical laws. So there .s an argument for nomic realism. Is there an argument against? You haven’t given one, just “articulated a claim”.
But that’s not the kind of reason that makes anything happen—it’s just a passive model.
That isn’t an argument against or for Platonic laws. Maybe it just is in a way that includes Platonic laws, maybe it isn’t.
I think you mean a hypothetical God with a 4D view of spacetime. And LD only has the ability to work out the future from a 3D snapshot. Yes, if you could see past present , you wouldn’t need in-the-mind laws to.make predictions..but, again that says nothing about in-the-territory, Platonic laws. Even if God doesn’t need in-the-mind laws, it’s still possible that reality needs in-the-territory laws to make things happen.
Anthropics and Boltzmann brains are also in the mind. As concepts.
What’s in the mind has to make sense, to fit together. Even if maths is all in the mind, maths problems still need to be solved. Saying maths is all in the mind does not tell you whether a particular theorem is true or false. Likewise , saying metaphysics is all in the mind does bot tell you that nomic realism is false, and anthropics true.
We have a meta map of the mind world relation, and if we assume a causal relation from the world to the mind, we can explain where new information comes from, and if we assume lawful behaviour in the world, we can explain regularities. Maybe these are all concepts we have, but we still need to fit them.together in a way that reduces the overall mystery, just as we still need to solve maths problems.
Fitting them.together in a way that reduces the overall mystery.
And if you want us to believe that the instrumentalist picture makes the most sense, you need to argue for it. The case for realism.l, by contrast, has been made.
The objective existence of physical laws, nomic realism, is a non anthropic answer which has already been put to you.
ETA
...or both, since...
Yudowsky’s argument that probability is subjective is flawed, because it rests on assumption that the existence of subjective probability implies the non existence of objective probabilty but the assumption is never justified. But you seem to buy into it anyway. And you seem to be basing your anti realism o n a similar unargued assumption.
I really don’t understand what “best explanation”, “true”, or “exist” mean, as stand-alone words divorced from predictions about observations we might ultimately make about them.
This isn’t just a semantic point, I think. If there are no observations we can make that ultimately reflect whether something exists in this (seems to me to be) free-floating sense, I don’t understand what it can mean to have evidence for or against such a proposition. So I don’t understand how I am even supposed to ever justifiably change my mind on this topic, even if I were to accept it as something worth discussing on the object-level.
A: “I am interested in knowing whether Platonic mathematical entities exist.”
B: “What does it mean for something to ‘exist’?”
A: “Well, it seems to be an irreducible metaphysical claim; something can exist, or not exist.”
B: “Um… I’m not sure about this whole notion of ‘metaphysics’. But anyway, trying a different track, do these Platonic mathematical entities interact with observable physical reality in any discernible way?”
A: “I mean, as a practical descriptor, we use those particular mathematical entities because they are useful to us when we model reality; but at their core, they are supposed to be Platonic. They are forms, not concrete entities. Nevertheless, we can reason about them; we can define them, relate them to one another, prove theorems about them. We can even develop better intuitions about them over time as we work with them more and more. Is that what do you mean by ‘discernible’?”
B: “Not exactly… Look, as Eliezer has said:
B (continuing): “So let’s think of the existence/non-existence status of Platonic math as the variable Y. Now, look, I am fine with accepting a broad perspective on the ‘variable’ X. Let it be an ocular observation, or the running of a scientific experiment, or a bunch of internal reasoning, or other stuff you might propose. I just want to know whether, given that these Platonic entities seem to live in an entirely separate magisterium, how is it that any observation/thought/conclusion we reach about the supposed existence of Platonic math (i.e., any particular value of Y) can result in different probabilities for the possible values of X?”
A: “You’re implicitly adopting a strong Bayesian perspective that you have neither argued for nor properly applied-”
B: “Fine! Drop the explicit probability stuff, then. I exist as a being embedded in the physical world. These mathematical entities are defined to exist (if they exist, which seems to be the question) in a Platonic realm that does not intersect this reality. After all, they are ideal forms, not concrete instances. So where is the entanglement between the two realms?”
A: “What do you mean by entanglement? I hope you’re not sneakily trying to assume a correspondence theory of truth yet again without justifying it.”
B: “What I mean is that I don’t understand how anything I do in this physical world that I belong to-”
A: “What makes you so sure you really live in a physical world? That’s the territory, not the map. All you have access to is the information given by your sense data and by your internal state of mind, including your memory. Maybe there is no outside world after all; maybe solipsism is true; maybe you live in an infinite-layer-deep simulation. Or maybe all of that is wrong and you actually are correct about living in some universe that runs on rough modifications of General Relativity and QFT, but even in that case, at the present moment you are totally not justified in assigning such confidence to this. You are merely assuming it instead, and this is precisely the type of metaphysical assumption you were pretending to be unable to wrap your head around at the start of the conversation.”
B: “Good Lord, fine! I’ll drop the physical universe assumption as well, for purposes of this conversation, even though I think I actually do have great justifications for being confident in it. But I won’t let the discussion get derailed any further in that direction. But I can still say that I am a concrete entity, precisely the type of being that shminux was contrasting the nature of when they mentioned Platonic mathematics. So I am concrete, and everything that goes on in my brain runs on the concrete me-stuff (I am intentionally avoiding the word ‘matter’), and yet I am supposed to have an opinion about the existence/non-existence of something that is entirely not concrete.”
A: “Isn’t that something you already conceded you were willing to try to do when you entered this dialogue? You could have walked away at the beginning or anytime after giving your whole spiel about beliefs paying rent in anticipated experiences.”
B: “Yes, I am willing to try to do that. But I don’t understand how I am supposed to ever change my mind on this topic, as I have already mentioned. What can possibly sway me one way or another when all variables X that I appear to be able to observe (or think about, etc.) are in the concrete realm, which is defined to be entirely non-intersecting with the Platonic realm? Does anything in this concrete realm have different values, or likelihoods, or entanglements, given different possible versions of whether the Platonic realm and its inhabitants exist? If math exists, is there anything that distinguishes this possibility? If math doesn’t exist, is there anything that distinguishes that possibility? What can count as epistemically justifiable updating (or, if you dislike the Bayesian connotations around that word, think ‘mind-changing’ instead) on this topic? As a general matter, I usually change my mind if I see new evidence or hear new good arguments, but I think of ‘good arguments’ as lines of logic and reasoning, whose validity and soundness implies we are more likely to be in a world where certain possibilities are true rather than others (when mulling over multiple hypotheses). What can that possibly mean in this context?”
A: [I’m not sure I can simulate A’s perspective after this point]
Nobody is saying that anything has to be divorced from prediction , in the sense that emperical evidence is ignored: the realist claim is that empirical evidence should be supplemented by other epistemic considerations.
Best explanation:- I already pointed out that EY is not an instrumentalist. For instance, he supports the MWI over the CI, although they make identical predictions. Why does he do that? For reasons of explanatory simplicity , consilience with the rest of physics, etc .as he says. That gives you a clue as to what “best explanation” is. (Your bafflement is baffling...it sometimes sounds like you have read the sequences, it sometimes sounds like you haven’t. Of course abduction, parsimony, etc are widely discussed in the mainstream literature as well ).
True:- mental concept corresponds to reality.
Exists:- You can take yourself as existing , and you can regard other putative entieties as existing if they gave some ability to causally interact with you. That’s another baffling one, because you actually use something like that definition in your argument against mathematical realism below.
Empirical evidence doesn’t exhaust justification. But you kind of know that, because you mention “good argument” below.
Apriori necessary truths can be novel and surprising to an agent, in practice, even though they are apriori and necessary in principle… because a realistic agent can’t instantaneously and perfectly correlate their mental contents, and don’t have an oracular list of every theory in their head. You are not a perfect Bayesian. You can notice a contradiction that you haven’t noticed before. You can be informed of a simpler explanation that you hadn’t formulated yourself.
Huh? I was debating nomic realism. Mathematical realism is another thing. Objectively existing natural laws obviously intersect with concrete observations , because if Gravity worked on an inverse cube law (etc), everything looked very different.
You don’t have to buy into realism about all things, or anti realism about all things. You can pick and choose. I don’t personally believe in Platonic realism about mathematics, for the same reasons you don’t. I believe Nomic realism is another question...its logically possible for physical laws to have been different.
@shminux defined the the thing he is arguing against as “Platonic” .. I don’t have to completely agree with that, nor do you. Maybe it’s just a mistake to think of nomic realism as Platonism. Platonism marries the idea of non-mental existence and the idea of non causality...But they can be treated separately.
what context? You’re talking about mathematical realism, I’m talking about nomic realism.
What have I said that makes you think I have departed from that?
@Shminux
Useful for what? If you terminally value uncovering the true nature of reality, as most scientists and philosophers do, you can hardly manage without some concept of “real”. If you only value making predictions, perhaps you don’t need the concept....But then the instrumentalist/realist divide is a difference in values, as I previously said, not a case of one side being wrong and the other side being right.
“Not a binary” is a different take from “not useful”.
“No direct access to reality” is a different claim to “no access to reality” is a different claim to “there is no reality” is a different to “the concept of reality is not useful”.l
It’s incoherent. What are these models, models of?
Thanks, I think you are doing a much better job voicing my objections than I would.
If push comes to shove, I would even dispute that “real” is a useful category once we start examining deep ontological claims. “Exist” is another emergent concept that is not even close to being binary, but more of a multidimensional spectrum (numbers, fairies and historical figures lie on some of the axes). I can provisionally accept that there is something like a universe that “exists”, but, as I said many years ago in another thread, I am much more comfortable with the ontology where it is models all the way down (and up and sideways and every which way). This is not really a critical point though. The critical point is that we have no direct access to the underlying reality, so we, as tiny embedded agents, are stuck dealing with the models regardless.
Thank you for your thoughtful and insightful reply! I think there is a lot more discussion that could be had on this topic, and we are not very far apart, but this is supposed to be a “shortform” thread.
I never liked The Simple Truth post, actually. I sided with Mark, the instrumentalist, whom Eliezer turned into what I termed back then as “instrawmantalist”. Though I am happy with the part
Rather recently Devs the show, which, for all its flaws, has a bunch of underrated philosophical highlights, had an episode with a somewhat similar storyline.
Anyway, appreciate your perspective.