NoR 1.5a Substantive rationality

This is one of a series of posts setting out my work on the Nature of Representation. You can view the whole series by following this link

In the last post I argued that it’s possible to construct an interpretation on which an agent is agnostic and indifferent to the character of the world outside her local bubble (the part of the world she can directly perceive and manipulate). This can be done in a way that still makes her “structurally” rational–formally and means-end consistent, updating coherently in the light of experience, and so forth. That’s trouble for structural radical interpretation, which said that what it was for an interpretation of Sally to be correct was for it to rationalize her dispositions to act in light of her course of experience. But we’ve seen that structurally rationality alone can’t rule out obviously incorrect interpretations on which Sally is agnostic about extra-bubbular matters, or even takes the world outside her bubble to be void.

The bubble puzzle refutes structural radical interpretation. But it is only a problem because of the unforced error taking the ‘rationalization’ relevant to radical interpretation to be structural rather than substantive. Recall: there’s nothing structurally irrational with future Tuesday indifference or a basic desire for a saucer of mud, And we might now add: nothing structurally irrational with taking one’s local bubble to be radically different in character from the world outside that local bubble. But forming such beliefs or desires is nevertheless not a reasonable place to end up, given standard, mundane course of experiences. Such beliefs and desires are irrational (given the available evidence) in an ordinary, non-technical sense, and it is only when we refine the notion to focus on  attitudes whose badness is distinctively “formal” that we generate these difficulties. Structural rationality is I think an important normative notion but it is not the right tool for this project.

The trouble is that the ordinary, broader notion of rationality is at this point inchoate. In the case of structural rationality, we have many ideas about what sorts of things are in the offing to be rational constrains, and we have a century of development of formal articulations of these constraints to model the account being proposed. This level of detail makes structural radical interpretation a predictive theory, since we can apply our existing theory of structural rationality to patterns of acts and experiences, and see what interpretations pass the test. If it weren’t predictive, we wouldn’t get the kind of nasty surprises we’ve just been worrying about!

If substantive radical interpretation is to be a credible option, we need something similar. We need some body of theory about substantive rationality that we can bring to candidate interpretations of an agent, which we can use to see what the theory predicts. The bubble puzzle makes this pressing. Are the interpretations Deviant or Paranoid substantively irrational, or at least less substantively rational than Original? On what basis shall we adjudicate such questions?

In what follows I add content to this theory in a number of ways:

  1. By endorsing specific assumptions about what a substantively rational agent is like.
  2. By endorsing restricted identifications: for example, that a substantively rational agent will have justified beliefs.
  3. By giving general theoretical glosses on the notion of substantive rationality.

In the applications in future posts, strategy 1—specific assumptions about  will be centre-stage. Any reading of substantive rationality on which those specific assumptions follow will do. But specific assumptions may look ad hoc without the wider theoretical context provided by the second and third. The second and third themselves get their power by linking substantive rationality to existing normative accounts, and will tend to involve some contentious choices. So let me spend some initial time here talking a bit about substantive rationality, in the spirit of approaches 2 and 3.

As regards 2, I will indeed take it that a (perfectly) substantively rational agent is one whose every belief (disbelief, suspension of belief) is justified. Further, I assume that subjects are, all else equal, more substantively rational the more their beliefs are justified by the evidence they possess. Substantive radical interpretation tells us, therefore, that ceteris paribus, the correct interpretation of Sally is a justification-maximizing one.

Similarly, I take it that a (perfectly) substantively rational agent is moral, and that agents all else equal are more substantively rational the more their actions are ethically correct given their beliefs/desires. Substantive radical interpretation tells us, therefore, that ceteris paribus, the correct interpretation of Sally is a morality-maximizing one.

These are just two ways to add content to substantive radical interpretation. More such constraints could be added, further fleshing out substantive rationality—for example, prudence as well as morality may be a desiderata on the practical side. These restricted identifications give a lot of content to work with, but if they’re not to be a laundry list, we need some general sense of what virtues we should include or not within “substantive rationality. This is where an overarching type-3 gloss comes in.

My central theoretical gloss is the following: that a substantively rational agent believes as they ought (or as is permissible), given their evidence, and an ideally reason-responsive agent acts they as they ought (or as is permissible), given their options and beliefs. Further:

  • The “oughts” in question factor in the agent’s limited perspective. Consider a bomb-disposal expert who is perfectly justified in believing that cutting the green wire will defuse the bomb, but where this will in fact detonate it. In some sense, perhaps, they ought not cut the wire (since that would lead to an explosion!) But in the relevant sense, cutting the wire is The Thing To Do, given their evidence.
  • The ought is “all things considered”. On the practical side, it aggregates moral, prudential (etc) considerations with the agent’s subjective preferences (/tastes/context) in whatever way is appropriate.
  • We shouldn’t presuppose that there is exactly one thing it’s all-things-considered okay to do in decision situation, or exactly one attitude it’s okay to have to a particular context. In the case of acts, for example, we can have ties, incommensurabilities, supererogatory options, or individual differences in taste, etc, generating normative non-uniqueness. The permissibility gloss allows for this—so long as an agent isn’t acting (or believing) in a way that’s all-things-considered wrong, they’ll count as substantively rational. For ease of exposition, I’ll drop the caveat here, and only reintroduce it where non-uniqueness is particularly salient.

Principles that favour justification-maximization fit this overarching gloss. Principles that favour truth-justification do not (even if on some reading or other, one ought to believe what’s true). Principles that favour morality-maximization fit this overarching gloss so long as the moral-ought in question factors in the agent’s factual uncertainty–overly “objective” moral oughts would not.

So when it comes to determining the correct interpretation, we should ideally find an interlocking hierarchy. Specific normative principles explain why this interpretation is favoured over that one. The specific normative principle is backed up by some general first-order normative theory (e.g. theory of justification, theory of morality), which is a determinant of substantive rationality via the kind of “restricted identifications” recently illustrated. And those restricted identifications need to be defensible as determinants of what the agent ought to believe and ought to do, on an appropriately information/evidence-sensitive reading of “ought”.

Turning back to our earlier examples of specific constraints of substantive rationality we can set them in context. Counterinductive belief formation is structurally rational, but doesn’t lead to epistemically justified beliefs. What you ought to believe is determined (at least in part) by what you’re epistemically justified in believing. So counterinductive beliefs are not substantively rational, and interpretations that attribute them are disfavoured. Being indifferent to what happens on future Tuesdays is structurally rational, but leads to imprudence—a failure to properly respect your own future interests. What you ought to do is determined (at least in part) by what it is prudent to do. So such desires are not substantively rational, and interpretations that attribute them are disfavoured. What about basic desires for saucers of mud? The underlying idea here, I take it, is that even idiosyncratic desires need to be for something valuable, and so substantively rational agents, though they may differ in their preferences, would always lock onto goals that are of value. Personally, I don’t know if I accept this piece of normative theory — or if it is a constraint on what the agent all things considered ought do, in the appropriate sense. So I’m agnostic, at this point, about whether this really is an example of something that would make an interpretation disfavoured. That shows that the framework I’ve introduced has teeth, and that we are no longer just dealing with an ad hoc list of psychological features that strike us as odd. To figure out whether desires for saucers of mud are to count as substantively irrational, we need to get into first-order normative theory.



Okay, so I think we have enough here to flesh out what substantive rationality is to be, and hence the content of substantive radical interpretation. In the next post, I’ll discuss how this resolves the bubble puzzle.

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