RobBensinger

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The academic contribution to AI safety seems large

I agree with Max's take. MIRI researchers still look at Alignment for Advanced Machine Learning Systems (AAMLS) problems periodically, but per Why I am not currently working on the AAMLS agenda, they mostly haven't felt the problems are tractable enough right now to warrant a heavy focus.

Nate describes our new work here: 2018 Update: Our New Research Directions.

Since 2016, actually “about half” of MIRI’s research has been on their ML agenda, apparently to cover the chance of prosaic AGI.

I don't think any of MIRI's major research programs, including AAMLS, have been focused on prosaic AI alignment. (I'd be interested to hear if Jessica or others disagree with me.)

Paul introduced prosaic AI alignment (in November 2016) with:

It’s conceivable that we will build “prosaic” AGI, which doesn’t reveal any fundamentally new ideas about the nature of intelligence or turn up any “unknown unknowns.” I think we wouldn’t know how to align such an AGI; moreover, in the process of building it, we wouldn’t necessarily learn anything that would make the alignment problem more approachable. So I think that understanding this case is a natural priority for research on AI alignment.

In contrast, I think of AAMLS as assuming that we'll need new deep insights into intelligence in order to actually align an AGI system. There's a large gulf between (1) "Prosaic AGI alignment is feasible" and (2) "AGI may be produced by techniques that are descended from current ML techniques" or (3) "Working with ML concepts and systems can help improve our understanding of AGI alignment", and I think of AAMLS as assuming some combination of 2 and 3, but not 1. From a post I wrote in July 2016:

[... AAMLS] is intended to help more in scenarios where advanced AI is relatively near and relatively directly descended from contemporary ML techniques, while our agent foundations agenda is more agnostic about when and how advanced AI will be developed.
As we recently wrote, we believe that developing a basic formal theory of highly reliable reasoning and decision-making “could make it possible to get very strong guarantees about the behavior of advanced AI systems — stronger than many currently think is possible, in a time when the most successful machine learning techniques are often poorly understood.” Without such a theory, AI alignment will be a much more difficult task.
The authors of “Concrete problems in AI safety” write that their own focus “is on the empirical study of practical safety problems in modern machine learning systems, which we believe is likely to be robustly useful across a broad variety of potential risks, both short- and long-term.” Their paper discusses a number of the same problems as the [AAMLS] agenda (or closely related ones), but directed more toward building on existing work and finding applications in present-day systems.
Where the agent foundations agenda can be said to follow the principle “start with the least well-understood long-term AI safety problems, since those seem likely to require the most work and are the likeliest to seriously alter our understanding of the overall problem space,” the concrete problems agenda [by Amodei, Olah, Steinhardt, Christiano, Schulman, and Mané] follows the principle “start with the long-term AI safety problems that are most applicable to systems today, since those problems are the easiest to connect to existing work by the AI research community.”
Taylor et al.’s new [AAMLS] agenda is less focused on present-day and near-future systems than “Concrete problems in AI safety,” but is more ML-oriented than the agent foundations agenda.
Are Humans 'Human Compatible'?

I agree that suffering is bad in all universes, for the reasons described in https://www.lesswrong.com/posts/zqwWicCLNBSA5Ssmn/by-which-it-may-be-judged. I'd say that "ethics... is not constituted by any feature of the universe" in the sense you note, but I'd point to our human brains if we were asking any question like:

• What explains why "suffering is bad" is true in all universes? How could an agent realistically discover this truth -- how do we filter out the false moral claims and zero in on the true ones, and how could an alien do the same?
Are Humans 'Human Compatible'?
I doubt that a utilitarian ethic is useful for maximizing of human preferences, since utilitarianism is impartial in the sense that it takes everyone's wellbeing into account, human or otherwise.

The view I would advocate is that something like utilitarianism (i.e., some form of impartial, species-indifferent welfare maximization) is a core part of human values. What I mean by 'human values' here isn't on your list; it's closer to an idealized version of our preferences: what we would prefer if we were smarter, more knowledgeable, had greater self-control.

Russels' assumption that "The machine’s only objective is to maximize the realization of human preferences" seems to assume some controversial and (to my judgement) highly implausible moral views. In particular, it is speciesistic, for why should only human preferences be maximized? Why not animal or machine preferences?

The language of "human-compatible" is very speciesist, since ethically we should want AGI to be "compatible" with all moral patients, human or not.

On the other hand, the idea of using human brains as a "starting point" for identifying what's moral makes sense. "Which ethical system is correct?" isn't written in the stars or in Plato's heaven; it seems like if the answer is encoded anywhere in the universe, it must be encoded in our brains (or in logical constructs out of brains).

The same is true for identifying the right notion of "impartial", "fair", "compassionate", "taking other species' welfare into account", etc.; to figure out the correct moral account of those important values, you would primarily need to learn facts about human brains. You'd then need to learn facts about non-humans' brains in order to implement the resultant impartiality procedure (because the relevant criterion, "impartiality", says that whether you have human DNA is utterly irrelevant to moral conduct).

The need to bootstrap from values encoded in our brains doesn't and shouldn't mean that humans are the only moral patients (or even that we're particularly important moral patients; insects could turn out to be utility monsters, for all we know today). Hence "human-compatible" is an unfortunate phrase here.

But it does mean that if, e.g., it turns out that cats' ultimate true preferences are to torture all species forever, we shouldn't give that particular preference equal decision weight. Speaking very loosely, the goal is more like 'ensuring all beings gets to have a good life', not like 'ensuring all species (however benevolent or sadistic they turn out to be) get an equal say in what kind of life all beings get to live'.

If there's a more benevolent species than humans, I'd hope that sufficiently advanced science could identify that species, and pass the buck to them. (In an odd sense, we're already building an alien species to defer to if we're constructing 'an idealized version of human preferences', since I would expect sufficiently idealized preferences to turn out to be pretty alien compared to the views human beings espouse today.)

I think it's reasonable to worry that given humans' flaws, humans might not in fact build AGI that 'ensures all beings get to have a good life'. But I do think that something like the latter is the goal; and when you ask me what physical facts in the world make that 'the goal', and what we would need to investigate in order to work out all the wrinkles and implementation details, I'm forced to initially point to facts about human (if only to identify the right notions of 'what a moral patient is' and 'how one ought to impartially take into account all moral patients' welfare').

EA Leaders Forum: Survey on EA priorities (data and analysis)

Speaking as a random EA — I work at an org that attended the forum (MIRI), but I didn't personally attend and am out of the loop on just about everything that was discussed there — I'd consider it a shame if CEA stopped sharing interesting take-aways from meetings based on an "everything should either be 100% publicly disclosed or 100% secret" policy.

I also don't think there's anything particularly odd about different orgs wanting different levels of public association with EA's brand, or having different levels of risk tolerance in general. EAs want to change the world, and the most leveraged positions in the world don't perfectly overlap with 'the most EA-friendly parts of the world'. Even in places where EA's reputation is fine today, it makes sense to have a diversified strategy where not every wonkish, well-informed, welfare-maximizing person in the world has equal exposure if EA's reputation takes a downturn in the future.

MIRI is happy to be EA-branded itself, but I'd consider it a pretty large mistake if MIRI started cutting itself off from everyone in the world who doesn't want to go all-in on EA (refuse to hear their arguments or recommendations, categorically disinvite them from any important meetings, etc.). So I feel like I'm logically forced to say this broad kind of thing is fine (without knowing enough about the implementation details in this particular case to weigh in on whether people are making all the right tradeoffs).

I'm Buck Shlegeris, I do research and outreach at MIRI, AMA

This is a good discussion! Ben, thank you for inspiring so many of these different paths we've been going down. :) At some point the hydra will have to stop growing, but I do think the intuitions you've been sharing are widespread enough that it's very worthwhile to have public discussion on these points.

Therefore, when a member of the rationalist community uses the word "decision theory" to refer to a decision procedure, they are talking about something that's pretty conceptually distinct from what philosophers typically have in mind. Discussions about what decision procedure performs best or about what decision procedure we should build into future AI systems don't directly speak to the questions that most academic "decision theorists" are actually debating with one another.

On the contrary:

• MIRI is more interested in identifying generalizations about good reasoning ("criteria of rightness") than in fully specifying a particular algorithm.
• MIRI does discuss decision algorithms in order to better understand decision-making, but this isn't different in kind from the ordinary way decision theorists hash things out. E.g., the traditional formulation of CDT is underspecified in dilemmas like Death in Damascus. Joyce and Arntzenius' response to this wasn't to go "algorithms are uncouth in our field"; it was to propose step-by-step procedures that they think capture the intuitions behind CDT and give satisfying recommendations for how to act.
• MIRI does discuss "what decision procedure performs best", but this isn't any different from traditional arguments in the field like "naive EDT is wrong because it performs poorly in the smoking lesion problem". Compared to the average decision theorist, the average rationalist puts somewhat more weight on some considerations and less weight on others, but this isn't different in kind from the ordinary disagreements that motivate different views within academic decision theory, and these disagreements about what weight to give categories of consideration are themselves amenable to argument.
• As I noted above, MIRI is primarily interested in decision theory for the sake of better understanding the nature of intelligence, optimization, embedded agency, etc., not for the sake of picking a "decision theory we should build into future AI systems". Again, this doesn't seem unlike the case of philosophers who think that decision theory arguments will help them reach conclusions about the nature of rationality.
I think it's totally conceivable that no criterion of rightness is correct (e.g. because the concept of a "criterion of rightness" turns out to be some spooky bit of nonsense that doesn't really map onto anything in the real world.)

Could you give an example of what the correctness of a meta-criterion like "Don't Make Things Worse" could in principle consist in?

I’m not looking here for a “reduction” in the sense of a full translation into other, simpler terms. I just want a way of making sense of how human brains can tell what’s “decision-theoretically normative” in cases like this.

Human brains didn’t evolve to have a primitive “normativity detector” that beeps every time a certain thing is Platonically Normative. Rather, different kinds of normativity can be understood by appeal to unmysterious matters like “things brains value as ends”, “things that are useful for various ends”, “things that accurately map states of affairs”...

When I think of other examples of normativity, my sense is that in every case there's at least one good account of why a human might be able to distinguish "truly" normative things from non-normative ones. E.g. (considering both epistemic and non-epistemic norms):

1. If I discover two alien species who disagree about the truth-value of "carbon atoms have six protons", I can evaluate their correctness by looking at the world and seeing whether their statement matches the world.

2. If I discover two alien species who disagree about the truth value of "pawns cannot move backwards in chess" or "there are statements in the language of Peano arithmetic that can neither be proved nor disproved in Peano arithmetic", then I can explain the rules of 'proving things about chess' or 'proving things about PA' as a symbol game, and write down strings of symbols that collectively constitute a 'proof' of the statement in question.

I can then assert that if any member of any species plays the relevant 'proof' game using the same rules, from now until the end of time, they will never prove the negation of my result, and (paper, pen, time, and ingenuity allowing) they will always be able to re-prove my result.

(I could further argue that these symbol games are useful ones to play, because various practical tasks are easier once we've accumulated enough knowledge about legal proofs in certain games. This usefulness itself provides a criteria for choosing between "follow through on the proof process" and "just start doodling things or writing random letters down".)

The above doesn't answer questions like "do the relevant symbols have Platonic objects as truthmakers or referents?", or "why do we live in a consistent universe?", or the like. But the above answer seems sufficient for rejecting any claim that there's something pointless, epistemically suspect, or unacceptably human-centric about affirming Gödel's first incompleteness theorem. The above is minimally sufficient grounds for going ahead and continuing to treat math as something more significant than theology, regardless of whether we then go on to articulate a more satisfying explanation of why these symbol games work the way they do.

3. If I discover two alien species who disagree about the truth-value of "suffering is terminally valuable", then I can think of at least two concrete ways to evaluate which parties are correct. First, I can look at the brains of a particular individual or group, see what that individual or group terminally values, and see whether the statement matches what's encoded in those brains. Commonly the group I use for this purpose is human beings, such that if an alien (or a housecat, etc.) terminally values suffering, I say that this is "wrong".

Alternatively, I can make different "wrong" predicates for each species: , , , , etc.

This has the disadvantage of maybe making it sound like all these values are on "equal footing" in an internally inconsistent way ("it's wrong to put undue weight on what's !", where the first "wrong" is secretly standing in for ""), but has the advantage of making it easy to see why the aliens' disagreement might be important and substantive, while still allowing that aliens' normative claims can be wrong (because they can be mistaken about their own core values).

The details of how to go from a brain to an encoding of "what's right" seem incredibly complex and open to debate, but it seems beyond reasonable dispute that if the information content of a set of terminal values is encoded anywhere in the universe, it's going to be in brains (or constructs from brains) rather than in patterns of interstellar dust, digits of pi, physical laws, etc.

If a criterion like “Don’t Make Things Worse” deserves a lot of weight, I want to know what that weight is coming from.

If the answer is “I know it has to come from something, but I don’t know what yet”, then that seems like a perfectly fine placeholder answer to me.

If the answer is “This is like the ‘terminal values’ case, in that (I hypothesize) it’s just an ineradicable component of what humans care about”, then that also seems structurally fine, though I’m extremely skeptical of the claim that the “warm glow of feeling causally efficacious” is important enough to outweigh other things of great value in the real world.

If the answer is “I think ‘Don’t Make Things Worse’ is instrumentally useful, i.e., more useful than UDT for achieving the other things humans want in life”, then I claim this is just false. But, again, this seems like the right kind of argument to be making; if CDT is better than UDT, then that betterness ought to consist in something.

I'm Buck Shlegeris, I do research and outreach at MIRI, AMA
Since (in a physically determinstic sense) the P_UDT agent could not have two-boxed, there's no relevant sense in which the agent should have two-boxed."

No, I don't endorse this argument. To simplify the discussion, let's assume that the Newcomb predictor is infallible. FDT agents, CDT agents, and EDT agents each get a decision: two-box (which gets you $1000 plus an empty box), or one-box (which gets you$1,000,000 and leaves the $1000 behind). Obviously, insofar as they are in fact following the instructions of their decision theory, there's only one possible outcome; but it would be odd to say that a decision stops being a decision just because it's determined by something. (What's the alternative?) I do endorse "given the predictor's perfect accuracy, it's impossible for the P_UDT agent to two-box and come away with$1,001,000". I also endorse "given the predictor's perfect accuracy, it's impossible for the P_CDT agent to two-box and come away with $1,001,000". Per the problem specification, no agent can two-box and get$1,001,000 or one-box and get $0. But this doesn't mean that no decision is made; it just means that the predictor can predict the decision early enough to fill the boxes accordingly. (Notably, the agent following P_CDT two-boxes because$1,001,000 > $1,000,000 and$1000 > $0, even though this "dominance" argument appeals to two outcomes that are known to be impossible just from the problem statement. I certainly don't think agents "should" try to achieve outcomes that are impossible from the problem specification itself. The reason agents get more utility than CDT in Newcomb's problem is that non-CDT agents take into account that the predictor is a predictor when they construct their counterfactuals.) In the transparent version of this dilemma, the agent who sees the$1M and one-boxes also "could have two-boxed", but if they had two-boxed, it would only have been after making a different observation. In that sense, if the agent has any lingering uncertainty about what they'll choose, the uncertainty goes away as soon as they see whether the box is full.

In general, it seems to me like all statements that evoke counterfactuals have something like this problem. For example, it is physically determined what sort of decision procedure we will build into any given AI system; only choice of decision procedure is physically consistent with the state of the world at the time the choice is made. So -- insofar as we accept this kind of objection from determinism -- there seems to be something problematically non-naturalistic about discussing what "would have happened" if we built in one decision procedure or another.

No, there's nothing non-naturalistic about this. Consider the scenario you and I are in. Simplifying somewhat, we can think of ourselves as each doing meta-reasoning to try to choose between different decision algorithms to follow going forward; where the new things we learn in this conversation are themselves a part of that meta-reasoning.

The meta-reasoning process is deterministic, just like the object-level decision algorithms are. But this doesn't mean that we can't choose between object-level decision algorithms. Rather, the meta-reasoning (in spite of having deterministic causes) chooses either "I think I'll follow P_FDT from now on" or "I think I'll follow P_CDT from now on". Then the chosen decision algorithm (in spite of also having deterministic causes) outputs choices about subsequent actions to take. Meta-processes that select between decision algorithms (to put into an AI, or to run in your own brain, or to recommend to other humans, etc.)) can make "real decisions", for exactly the same reason (and in exactly the same sense) that the decision algorithms in question can make real decisions.

It isn't problematic that all these processes requires us to consider counterfactuals that (if we were omniscient) we would perceive as inconsistent/impossible. Deliberation, both at the object level and at the meta level, just is the process of determining the unique and only possible decision. Yet because we are uncertain about the outcome of the deliberation while deliberating, and because the details of the deliberation process do determine our decision (even as these details themselves have preceding causes), it feels from the inside of this process as though both options are "live", are possible, until the very moment we decide.

I'm Buck Shlegeris, I do research and outreach at MIRI, AMA
But there's nothing logically inconsistent about believing both (a) that R_CDT is true and (b) that agents should not implement P_CDT.

If the thing being argued for is "R_CDT plus P_SONOFCDT", then that makes sense to me, but is vulnerable to all the arguments I've been making: Son-of-CDT is in a sense the worst of both worlds, since it gets less utility than FDT and lacks CDT's "Don't Make Things Worse" principle.

If the thing being argued for is "R_CDT plus P_FDT", then I don't understand the argument. In what sense is P_FDT compatible with, or conducive to, R_CDT? What advantage does this have over "R_FDT plus P_FDT"? (Indeed, what difference between the two views would be intended here?)

So why shouldn't I believe that R_CDT is true? The argument needs an additional step. And it seems to me like the most addition step here involves an intuition that the criterion of rightness would not be not self-effacing.

The argument against "R_CDT plus P_SONOFCDT" doesn't require any mention of self-effacingness; it's entirely sufficient to note that P_SONOFCDT gets less utility than P_FDT.

The argument against "R_CDT plus P_FDT" seems to demand some reference to self-effacingness or inconsistency, or triviality / lack of teeth. But I don't understand what this view would mean or why anyone would endorse it (and I don't take you to be endorsing it).

For example, are we talking about expected lifetime utility from a causal or evidential perspective? But I don't think this ambiguity matters much for the argument.

We want to evaluate actual average utility rather than expected utility, since the different decision theories are different theories of what "expected utility" means.

I'm Buck Shlegeris, I do research and outreach at MIRI, AMA

So, as an experiment, I'm going to be a very obstinate reductionist in this comment. I'll insist that a lot of these hard-seeming concepts aren't so hard.

Many of them are complicated, in the fashion of "knowledge" -- they admit an endless variety of edge cases and exceptions -- but these complications are quirks of human cognition and language rather than deep insights into ultimate metaphysical reality. And where there's a simple core we can point to, that core generally isn't mysterious.

It may be inconvenient to paraphrase the term away (e.g., because it packages together several distinct things in a nice concise way, or has important emotional connotations, or does important speech-act work like encouraging a behavior). But when I say it "isn't mysterious", I mean it's pretty easy to see how the concept can crop up in human thought even if it doesn't belong on the short list of deep fundamental cosmic structure terms.

I would say that there's also at least a fourth way that philosophers often use the word "rational," which is also the main way I use the word "rational." This is to refer to an irreducibly normative concept.

Why is this a fourth way? My natural response is to say that normativity itself is either a messy, parochial human concept (like "love," "knowledge," "France") , or it's not (in which case it goes in bucket 2).

Some examples of concepts that are arguably irreducible are "truth," "set," "property," "physical," "existance," and "point."

Picking on the concept here that seems like the odd one out to me: I feel confident that there isn't a cosmic law (of nature, or of metaphysics, etc.) that includes "truth" as a primitive (unless the list of primitives is incomprehensibly long). I could see an argument for concepts like "intentionality/reference", "assertion", or "state of affairs", though the former two strike me as easy to explain in simple physical terms.

Mundane empirical "truth" seems completely straightforward. Then there's the truth of sentences like "Frodo is a hobbit", "2+2=4", "I could have been the president", "Hamburgers are more delicious than battery acid"... Some of these are easier or harder to make sense of in the naive correspondence model, but regardless, it seems clear that our colloquial use of the word "true" to refer to all these different statements is pre-philosophical, and doesn't reflect anything deeper than that "each of these sentences at least superficially looks like it's asserting some state of affairs, and each sentence satisfies the conventional assertion-conditions of our linguistic community".

I think that philosophers are really good at drilling down on a lot of interesting details and creative models for how we can try to tie these disparate speech-acts together. But I think there's also a common failure mode in philosophy of treating these questions as deeper, more mysterious, or more joint-carving than the facts warrant. Just because you can argue about the truthmakers of "Frodo is a hobbit" doesn't mean you're learning something deep about the universe (or even something particularly deep about human cognition) in the process.

[Parfit:] It is hard to explain the concept of a reason, or what the phrase ‘a reason’ means. Facts give us reasons, we might say, when they count in favour of our having some attitude, or our acting in some way. But ‘counts in favour of’ means roughly ‘gives a reason for’. Like some other fundamental concepts, such as those involved in our thoughts about time, consciousness, and possibility, the concept of a reason is indefinable in the sense that it cannot be helpfully explained merely by using words.

Suppose I build a robot that updates hypotheses based on observations, then selects actions that its hypotheses suggest will help it best achieve some goal. When the robot is deciding which hypotheses to put more confidence in based on an observation, we can imagine it thinking, "To what extent is observation o a [WORD] to believe hypothesis h?" When the robot is deciding whether it assigns enough probability to h to choose an action a, we can imagine it thinking, "To what extent is P(h)=0.7 a [WORD] to choose action a?" As a shorthand, when observation o updates a hypothesis h that favors an action a, the robot can also ask to what extent o itself is a [WORD] to choose a.

When two robots meet, we can moreover add that they negotiate a joint "compromise" goal that allows them to work together rather than fight each other for resources. In communicating with each other, they then start also using "[WORD]" where an action is being evaluated relative to the joint goal, not just the robot's original goal.

Thus when Robot A tells Robot B "I assign probability 90% to 'it's noon', which is [WORD] to have lunch", A may be trying to communicate that A wants to eat, or that A thinks eating will serve A and B's joint goal. (This gets even messier if the robots have an incentive to obfuscate which actions and action-recommendations are motivated by the personal goal vs. the joint goal.)

If you decide to relabel "[WORD]" as "reason", I claim that this captures a decent chunk of how people use the phrase "a reason". "Reason" is a suitcase word, but that doesn't mean there are no similarities between e.g. "data my goals endorse using to adjust the probability of a given hypothesis" and "probabilities-of-hypotheses my goals endorse using to select an action"), or that the similarity is mysterious and ineffable.

(I recognize that the above story leaves out a lot of important and interesting stuff. Though past a certain point, I think the details will start to become Gettier-case nitpicks, as with most concepts.)

For example, suppose we follow a suggestion once made by Eliezer to reduce the concept of "a rational choice" to the concept of "a winning choice" (or, in line with the type-2 conception you mention, a "utility-maximizing choice").

That essay isn't trying to "reduce" the term "rationality" in the sense of taking a pre-existing word and unpacking or translating it. The essay is saying that what matters is utility, and if a human being gets too invested in verbal definitions of "what the right thing to do is", they risk losing sight of the thing they actually care about and were originally in the game to try to achieve (i.e., their utility).

Therefore: if you're going to use words like "rationality", make sure that the words in question won't cause you to shoot yourself in the foot and take actions that will end up costing you utility (e.g., costing human lives, costing years of averted suffering, costing money, costing anything or everything). And if you aren't using "rationality" in a safe "nailed-to-utility" way, make sure that you're willing to turn on a time and stop being "rational" the second your conception of rationality starts telling you to throw away value.

It ultimately seems hard, at least to me, to make non-vacuous true claims about what it's "rational" to do withoit evoking a non-reducible notion of "rationality."

"Rationality" is a suitcase word. It refers to lots of different things. On LessWrong, examples include not just "(systematized) winning" but (as noted in the essay) "Bayesian reasoning", or in Rationality: Appreciating Cognitive Algorithms, "cognitive algorithms or mental processes that systematically produce belief-accuracy or goal-achievement". In philosophy, the list is a lot longer.

The common denominator seems to largely be "something something reasoning / deliberation" plus (as you note) "something something normativity / desirability / recommendedness / requiredness".

The idea of "normativity" doesn't currently seem that mysterious to me either, though you're welcome to provide perplexing examples. My initial take is that it seems to be a suitcase word containing a bunch of ideas tied to:

• Goals/preferences/values, especially overridingly strong ones.
• Encouraged, endorsed, mandated, or praised conduct.

Encouraging, endorsing, mandating, and praising are speech-acts that seem very central to how humans perceive and intervene on social situations; and social situations seem pretty central to human cognition overall. So I don't think it's particularly surprising if words associated with such loaded ideas would have fairly distinctive connotations and seem to resist reduction, especially reduction that neglects the pragmatic dimensions of human communication and only considers the semantic dimension.

I'm Buck Shlegeris, I do research and outreach at MIRI, AMA
Whereas others think self-consistency is more important.

The main argument against CDT (in my view) is that it tends to get you less utility (regardless of whether you add self-modification so it can switch to other decision theories). Self-consistency is a secondary issue.

It's not clear to me that the justification for CDT is more circular than the justification for FDT. Doesn't it come down to which principles you favor?

FDT gets you more utility than CDT. If you value literally anything in life more than you value "which ritual do I use to make my decisions?", then you should go with FDT over CDT; that's the core argument.

This argument for FDT would be question-begging if CDT proponents rejected utility as a desirable thing. But instead CDT proponents who are familiar with FDT agree utility is a positive, and either (a) they think there's no meaningful sense in which FDT systematically gets more utility than CDT (which I think is adequately refuted by Abram Demski), or (b) they think that CDT has other advantages that outweigh the loss of utility (e.g., CDT feels more intuitive to them).

The latter argument for CDT isn't circular, but as a fan of utility (i.e., of literally anything else in life), it seems very weak to me.