It seems to me, rather, that people often talk about updating your credences in accordance with Bayes’ rule and maximizing the expected fulfillment of your current desires as the correct things to do.
It’s important to disentangle two claims:
1. In general, if you have the goal of understanding the world, or any other goal that relies on doing so, being Bayesian will allow you to achieve it to a greater extent than any other approach (in the limit of infinite compute).
2. Regardless of your goals, you should be Bayesian anyway.
Believing #2 commits you to normative realism as I understand the term, but believing #1 doesn’t - #1 is simply an empirical claim about what types of cognition tend to do best towards a broad class of goals. I think that many rationalists would defend #1, and few would defend #2 - if you disagree, I’d be interested in seeing examples of the latter. (One test is by asking “Aside from moral considerations, if someone’s only goal is to have false beliefs right now, should they believe true things anyway?”) Either way, I agree with Wei that distinguishing between moral normativity and epistemic normativity is crucial for fruitful discussions on this topic.
Another way of framing this distinction: assume there’s one true theory of physics, call it T. Then someone might make the claim “Modelling the universe using T is the correct way to do so (in the limit of having infinite compute available).” This is analogous to claim #1, and believing this claim does not commit you to normative realism, because it does not imply that anyone should want to model the universe correctly.
It might also be useful to clarify that in ricraz’s recent post criticizing “realism about rationality,” several of the attitudes listed aren’t directly related to “realism” in the sense of this post.
I would characterise “realism about rationality” as approximately equivalent to claim #1 above (plus a few other similar claims). In particular, it is a belief about whether there is a set of simple ideas which elegantly describe the sort of “agents” who do well at their “goals”—not a belief about the normative force of those ideas. Of course, under most reasonable interpretations of #2, the truth of #2 implies #1, but not vice versa.
Eliezer used some pretty strong normative language when talking about having false beliefs, e.g. in Dark Side Epistemology:
Steven Kaas said, “Promoting less than maximally accurate beliefs is an act of sabotage. Don’t do it to anyone unless you’d also slash their tires.” Giving someone a false belief to protect—convincing them that the belief itself must be defended from any thought that seems to threaten it—well, you shouldn’t do that to someone unless you’d also give them a frontal lobotomy.
The quote from Eliezer is consistent with #1, since it’s bad to undermine people’s ability to achieve their goals.
More generally, you might believe that it’s morally normative to promote true beliefs (e.g. because they lead to better outcomes) but not believe that it’s epistemically normative, in a realist sense, to do so (e.g. the question I asked above, about whether you “should” have true beliefs even when there are no morally relevant consequences and it doesn’t further your goals).
In general, if you have the goal of understanding the world, or any other goal that relies on doing so, being Bayesian will allow you to achieve it to a greater extent than any other approach (in the limit of infinite compute).
Regardless of your goals, you should be Bayesian anyway.
Believing #2 commits you to normative realism as I understand the term, but believing #1 doesn’t - #1 is simply an empirical claim about what types of cognition tend to do best towards a broad class of goals. I think that many rationalists would defend #1, and few would defend #2 - if you disagree, I’d be interested in seeing examples of the latter.
I don’t necessarily think that #2 is a common belief. But I do have the impression that many people would at least endorse this equally normative claim: “If you have the goal of understanding the world, you should be a Bayesian.”
In general—at least in the context of the concepts/definitions in this post—the inclusion of an “if” clause doesn’t prevent a claim from being normative. So, for example, the claim “You should go to Spain if you want to go to Spain” isn’t relevantly different from the claim “You should give money to charity if you have enough money to live comfortably.”
Either way, I agree with Wei that distinguishing between moral normativity and epistemic normativity is crucial for fruitful discussions on this topic.
I agree there’s an important distinction, but it doesn’t necessarily seem that deep to me.
For example: We can define different “epistemic utility functions” that map {agent’s credences; state of the world} to real values and then discuss theories like Bayesianism in the context of “epistemicdecision theory,” in relatively close analogy with traditional (practical) decision theory.
It seems like some theories—e.g. certain theories that say we should have faith in the existance of God, or theories that say that we shouldn’t take into account certain traits when forming impressions of people—might also be classified as both moral and epistemological.
But I do have the impression that many people would at least endorse this equally normative claim: “If you have the goal of understanding the world, you should be a Bayesian.”
Okay, this seems like a crux of our disagreement. This statement seems pretty much equivalent to my statement #1 in almost all practical contexts. Can you point out how you think they differ?
I agree that some statements of that form seem normative: e.g. “You should go to Spain if you want to go to Spain”. However, that seems like an exception to me, because it provides no useful information about how to achieve the goal, and so from contextual clues would be interpreted as “I endorse your desire to go to Spain”. Consider instead “If you want to murder someone without getting caught, you should plan carefully”, which very much lacks endorsement. Or even “If you want to get to the bakery, you should take a left turn here.” How do you feel about the normativity of the last statement in particular? How does it practically differ from “The most convenient way to get to the bakery from here is to take a left turn”? Clearly that’s something almost everyone is a realist about (assuming a shared understanding of “convenient”) at Less Wrong and elsewhere.
In general—at least in the context of the concepts/definitions in this post—the inclusion of an “if” clause doesn’t prevent a claim from being normative. So, for example, the claim “You should go to Spain if you want to go to Spain” isn’t relevantly different from the claim “You should give money to charity if you have enough money to live comfortably.”
I think there’s a difference between a moral statement with conditions, and a statement about what is best to do given your goals (roughly corresponding to the difference between Kant’s categorical and hypothetical imperatives). “You should give money to charity if you have enough money to live comfortably” is an example of the former—it’s the latter which I’m saying aren’t normative in any useful sense.
Okay, this seems like a crux of our disagreement. This statement seems pretty much equivalent to my statement #1 in almost all practical contexts. Can you point out how you think they differ?
This stuff is definitely a bit tricky to talk about, since people can use the word “should” in different ways. I think that sometimes when people say “You should do X if you want Y” they do basically just mean to say “If you do X you will receive Y.” But it doesn’t seem to me like this is always the case.
A couple examples:
1. “Bayesian updating has a certain asymptoptic convergence property, in the limit of infinite experience and infinite compute. So if you want to understand the world, you should be a Bayesian.”
If the first and second sentence were meant to communicate the same thing, then the second would be totally vacuous given the first. Anyone who accepted the first sentence could not intelligibly disagree with or even really consider disagreeing with the second. But I don’t think that people who say things like this typically mean for the second sentence to be vacuous or typically regard disagreement as unintelligible.
Suppose, for example, that I responded to this claim by saying something like: “I disagree. Since we only have finite lives, asymptoptic convergence properties don’t have direct relevance. I think we should instead use a different ‘risk averse’ updating rule that, for agents with finite lives, more strongly reduces the likelihood of ending up with especially inaccurate beliefs about key features of the world.”
The speaker might think I’m wrong. But if the speaker thinks that what I’m saying constitutes intelligible disagreement with their claim, then it seems like this means their claim is in fact a distinct normative one.
2. (To someone with no CS background) “If you want to understand the world, you should be a Bayesian.”
If this sentence were meant to communicate the same thing as the claim about asymptotic convergence, then the speaker shouldn’t expect the listener to understand what they’re saying (even if the speaker has already explained what it means to be a Bayesian). Most people don’t naturally understand or care at all about asymptotic convergence properties.
1. “Bayesian updating has a certain asymptoptic convergence property, in the limit of infinite experience and infinite compute. So if you want to understand the world, you should be a Bayesian.”
If the first and second sentence were meant to communicate the same thing, then the second would be totally vacuous given the first.
I was a little imprecise in saying that they’re exactly equivalent—the second sentence should also have a “in the limit of infinite compute” qualification. Or else we need a hidden assumption like “These asymptotic convergence properties give us reason to believe that even low-compute approximations to Bayesianism are very good ways to understand the world.” This is usually left implicit, but it allows us to think of “if you want to understand the world, you should be (approximately) a Bayesian” as an empirical claim not a normative one. For this to actually be an example of normativity, it needs to be the case that some people consider this hidden assumption unnecessary and would endorse claims like “You should use low-compute approximations to Bayesianism because Bayesianism has certain asymptotic convergence properties, even if those properties don’t give us any reason to think that low-compute approximations to Bayesianism help you understand the world better.” Do you expect that people would endorse this?
Hmm, I think focusing on a simpler case might be better for getting at the crux.
Suppose Alice says: “Eating meat is the most effective way to get protein. So if you want to get protein, you should eat meat.”
And then Bob, an animal welfare person, responds: “You’re wrong, people shouldn’t eat meat no matter how much they care about getting protein.”
If Alice doesn’t mean for her second sentence to be totally redundant—or if she is able to interpret Bob’s response as an intelligible (if incorrect) statement of disagreement with her second sentence—then that suggests her second sentence actually constitutes a substantively normative claim. Her second sentence isn’t just repeating the same non-normative claim as the first one.
I definitely don’t think that all “If you want X, do Y” claims are best understood as normative claims. It’s possible that when people make claims of this form about Bayesianism, and other commonly discussed topics, they’re not really saying anything normative. But a decent chunk of statements of this form do strike me as difficult to interpret in non-normative terms.
If Alice doesn’t mean for her second sentence to be totally redundant—or if she is able to interpret Bob’s response as an intelligible (if incorrect) statement of disagreement with her second sentence—then that suggests her second sentence actually constitutes a substantively normative claim.
I don’t think you can declare a sentence redundant without also considering the pragmatic aspects of meaning. In this example, Alice’s second sentence is a stronger claim than the first, because it again contains an implicit clause: “If you want to get protein, and you don’t have any other relevant goals, you should eat meat”. Or maybe it’s more like “If you want to get protein, and your other goals are standard ones, you should eat meat.”
Compare: Alice says “Jumping off cliffs without a parachute is a quick way to feel very excited. If you want to feel excited, you should jump off cliffs without a parachute.” Bob says “No you shouldn’t, because you’ll die.” Alice’s first sentence is true, and her second sentence is false, so they can’t be equivalent—but both of them can be interpreted as goal-conditional empirical sentences. It’s just the case that when you make broad statements, pragmatically you are assuming a “normal” set of goals.
If she is able to interpret Bob’s response as an intelligible (if incorrect) statement of disagreement with her second sentence
It’s not entirely unintelligible, because Alice is relying on an implicit premise of “standard goals” I mentioned above, and the reason people like Bob are so outspoken on this issue is because they’re trying to change that norm of what we consider “standard goals”. I do think that if Alice really understood normativity, she would tell Bob that she was trying to make a different type of claim to his one, because his was normative and hers wasn’t—while conceding that he had reason to find the pragmatics of her sentence objectionable.
Also, though, you’ve picked a case where the disputed statement is often used both in empirical ways and in normative ways. This is the least clear sort of example (especially since, pragmatically, when you repeat almost the same thing twice, it makes people think you’re implying something different). The vast majority of examples of people using “if you want..., then you should...” seem clearly empirical to me—including many that are in morally relevant domains, where the pragmatics make their empirical nature clear:
A: “If you want to murder someone without getting caught, you should plan carefully.”
B: “No you shouldn’t, because you shouldn’t murder people.”
A: “Well obviously you shouldn’t murder people, but I’m just saying that if you wanted to, planning would make things much easier.”
Upon further thought, maybe just splitting up #1 and #2 is oversimplifying. There’s probably a position #1.5, which is more like “Words like “goals” and “beliefs” only make sense to the extent that they’re applied to Bayesians with utility functions—every other approach to understanding agenthood is irredeemably flawed.” This gets pretty close to normative realism because you’re only left with one possible theory, but it’s still not making any realist normative claims (even if you think that goals and beliefs are morally relevant, as long as you’re also a moral anti-realist). Maybe a relevant analogy: you might believe that using any axioms except the ZFC axioms will make maths totally incoherent, while not actually holding any opinion on whether the ZFC axioms are “true”.
It’s important to disentangle two claims:
1. In general, if you have the goal of understanding the world, or any other goal that relies on doing so, being Bayesian will allow you to achieve it to a greater extent than any other approach (in the limit of infinite compute).
2. Regardless of your goals, you should be Bayesian anyway.
Believing #2 commits you to normative realism as I understand the term, but believing #1 doesn’t - #1 is simply an empirical claim about what types of cognition tend to do best towards a broad class of goals. I think that many rationalists would defend #1, and few would defend #2 - if you disagree, I’d be interested in seeing examples of the latter. (One test is by asking “Aside from moral considerations, if someone’s only goal is to have false beliefs right now, should they believe true things anyway?”) Either way, I agree with Wei that distinguishing between moral normativity and epistemic normativity is crucial for fruitful discussions on this topic.
Another way of framing this distinction: assume there’s one true theory of physics, call it T. Then someone might make the claim “Modelling the universe using T is the correct way to do so (in the limit of having infinite compute available).” This is analogous to claim #1, and believing this claim does not commit you to normative realism, because it does not imply that anyone should want to model the universe correctly.
I would characterise “realism about rationality” as approximately equivalent to claim #1 above (plus a few other similar claims). In particular, it is a belief about whether there is a set of simple ideas which elegantly describe the sort of “agents” who do well at their “goals”—not a belief about the normative force of those ideas. Of course, under most reasonable interpretations of #2, the truth of #2 implies #1, but not vice versa.
Eliezer used some pretty strong normative language when talking about having false beliefs, e.g. in Dark Side Epistemology:
The quote from Eliezer is consistent with #1, since it’s bad to undermine people’s ability to achieve their goals.
More generally, you might believe that it’s morally normative to promote true beliefs (e.g. because they lead to better outcomes) but not believe that it’s epistemically normative, in a realist sense, to do so (e.g. the question I asked above, about whether you “should” have true beliefs even when there are no morally relevant consequences and it doesn’t further your goals).
I don’t necessarily think that #2 is a common belief. But I do have the impression that many people would at least endorse this equally normative claim: “If you have the goal of understanding the world, you should be a Bayesian.”
In general—at least in the context of the concepts/definitions in this post—the inclusion of an “if” clause doesn’t prevent a claim from being normative. So, for example, the claim “You should go to Spain if you want to go to Spain” isn’t relevantly different from the claim “You should give money to charity if you have enough money to live comfortably.”
I agree there’s an important distinction, but it doesn’t necessarily seem that deep to me.
For example: We can define different “epistemic utility functions” that map {agent’s credences; state of the world} to real values and then discuss theories like Bayesianism in the context of “epistemic decision theory,” in relatively close analogy with traditional (practical) decision theory.
It seems like some theories—e.g. certain theories that say we should have faith in the existance of God, or theories that say that we shouldn’t take into account certain traits when forming impressions of people—might also be classified as both moral and epistemological.
Okay, this seems like a crux of our disagreement. This statement seems pretty much equivalent to my statement #1 in almost all practical contexts. Can you point out how you think they differ?
I agree that some statements of that form seem normative: e.g. “You should go to Spain if you want to go to Spain”. However, that seems like an exception to me, because it provides no useful information about how to achieve the goal, and so from contextual clues would be interpreted as “I endorse your desire to go to Spain”. Consider instead “If you want to murder someone without getting caught, you should plan carefully”, which very much lacks endorsement. Or even “If you want to get to the bakery, you should take a left turn here.” How do you feel about the normativity of the last statement in particular? How does it practically differ from “The most convenient way to get to the bakery from here is to take a left turn”? Clearly that’s something almost everyone is a realist about (assuming a shared understanding of “convenient”) at Less Wrong and elsewhere.
I think there’s a difference between a moral statement with conditions, and a statement about what is best to do given your goals (roughly corresponding to the difference between Kant’s categorical and hypothetical imperatives). “You should give money to charity if you have enough money to live comfortably” is an example of the former—it’s the latter which I’m saying aren’t normative in any useful sense.
This stuff is definitely a bit tricky to talk about, since people can use the word “should” in different ways. I think that sometimes when people say “You should do X if you want Y” they do basically just mean to say “If you do X you will receive Y.” But it doesn’t seem to me like this is always the case.
A couple examples:
1. “Bayesian updating has a certain asymptoptic convergence property, in the limit of infinite experience and infinite compute. So if you want to understand the world, you should be a Bayesian.”
If the first and second sentence were meant to communicate the same thing, then the second would be totally vacuous given the first. Anyone who accepted the first sentence could not intelligibly disagree with or even really consider disagreeing with the second. But I don’t think that people who say things like this typically mean for the second sentence to be vacuous or typically regard disagreement as unintelligible.
Suppose, for example, that I responded to this claim by saying something like: “I disagree. Since we only have finite lives, asymptoptic convergence properties don’t have direct relevance. I think we should instead use a different ‘risk averse’ updating rule that, for agents with finite lives, more strongly reduces the likelihood of ending up with especially inaccurate beliefs about key features of the world.”
The speaker might think I’m wrong. But if the speaker thinks that what I’m saying constitutes intelligible disagreement with their claim, then it seems like this means their claim is in fact a distinct normative one.
2. (To someone with no CS background) “If you want to understand the world, you should be a Bayesian.”
If this sentence were meant to communicate the same thing as the claim about asymptotic convergence, then the speaker shouldn’t expect the listener to understand what they’re saying (even if the speaker has already explained what it means to be a Bayesian). Most people don’t naturally understand or care at all about asymptotic convergence properties.
I was a little imprecise in saying that they’re exactly equivalent—the second sentence should also have a “in the limit of infinite compute” qualification. Or else we need a hidden assumption like “These asymptotic convergence properties give us reason to believe that even low-compute approximations to Bayesianism are very good ways to understand the world.” This is usually left implicit, but it allows us to think of “if you want to understand the world, you should be (approximately) a Bayesian” as an empirical claim not a normative one. For this to actually be an example of normativity, it needs to be the case that some people consider this hidden assumption unnecessary and would endorse claims like “You should use low-compute approximations to Bayesianism because Bayesianism has certain asymptotic convergence properties, even if those properties don’t give us any reason to think that low-compute approximations to Bayesianism help you understand the world better.” Do you expect that people would endorse this?
Hmm, I think focusing on a simpler case might be better for getting at the crux.
Suppose Alice says: “Eating meat is the most effective way to get protein. So if you want to get protein, you should eat meat.”
And then Bob, an animal welfare person, responds: “You’re wrong, people shouldn’t eat meat no matter how much they care about getting protein.”
If Alice doesn’t mean for her second sentence to be totally redundant—or if she is able to interpret Bob’s response as an intelligible (if incorrect) statement of disagreement with her second sentence—then that suggests her second sentence actually constitutes a substantively normative claim. Her second sentence isn’t just repeating the same non-normative claim as the first one.
I definitely don’t think that all “If you want X, do Y” claims are best understood as normative claims. It’s possible that when people make claims of this form about Bayesianism, and other commonly discussed topics, they’re not really saying anything normative. But a decent chunk of statements of this form do strike me as difficult to interpret in non-normative terms.
I don’t think you can declare a sentence redundant without also considering the pragmatic aspects of meaning. In this example, Alice’s second sentence is a stronger claim than the first, because it again contains an implicit clause: “If you want to get protein, and you don’t have any other relevant goals, you should eat meat”. Or maybe it’s more like “If you want to get protein, and your other goals are standard ones, you should eat meat.”
Compare: Alice says “Jumping off cliffs without a parachute is a quick way to feel very excited. If you want to feel excited, you should jump off cliffs without a parachute.” Bob says “No you shouldn’t, because you’ll die.” Alice’s first sentence is true, and her second sentence is false, so they can’t be equivalent—but both of them can be interpreted as goal-conditional empirical sentences. It’s just the case that when you make broad statements, pragmatically you are assuming a “normal” set of goals.
It’s not entirely unintelligible, because Alice is relying on an implicit premise of “standard goals” I mentioned above, and the reason people like Bob are so outspoken on this issue is because they’re trying to change that norm of what we consider “standard goals”. I do think that if Alice really understood normativity, she would tell Bob that she was trying to make a different type of claim to his one, because his was normative and hers wasn’t—while conceding that he had reason to find the pragmatics of her sentence objectionable.
Also, though, you’ve picked a case where the disputed statement is often used both in empirical ways and in normative ways. This is the least clear sort of example (especially since, pragmatically, when you repeat almost the same thing twice, it makes people think you’re implying something different). The vast majority of examples of people using “if you want..., then you should...” seem clearly empirical to me—including many that are in morally relevant domains, where the pragmatics make their empirical nature clear:
A: “If you want to murder someone without getting caught, you should plan carefully.”
B: “No you shouldn’t, because you shouldn’t murder people.”
A: “Well obviously you shouldn’t murder people, but I’m just saying that if you wanted to, planning would make things much easier.”
Upon further thought, maybe just splitting up #1 and #2 is oversimplifying. There’s probably a position #1.5, which is more like “Words like “goals” and “beliefs” only make sense to the extent that they’re applied to Bayesians with utility functions—every other approach to understanding agenthood is irredeemably flawed.” This gets pretty close to normative realism because you’re only left with one possible theory, but it’s still not making any realist normative claims (even if you think that goals and beliefs are morally relevant, as long as you’re also a moral anti-realist). Maybe a relevant analogy: you might believe that using any axioms except the ZFC axioms will make maths totally incoherent, while not actually holding any opinion on whether the ZFC axioms are “true”.