NoR 1.5b: Popping the bubble puzzle.

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

To recap: I distinguished two forms of radical interpretation: structural and substantive, based on a distinction between two corresponding readings of “rationalization”. Structural radical interpretation has a counterexample in the bubble puzzle: obviously wrong interpretations of an agent can perfectly structurally-rationalize her actions given her course of experience. Attention turns then to substantive radical interpretation, but that’s going to be no good if all we have to offer by way of fleshing out “substantive rationality” is an ad hoc laundry list of odd-seeming psychological states. But I’ve set out a principled framework which we use to explain and predict which interpretations will be counted as substantively rational, and which not. In this post, I’ll turn back to the bubble puzzle, and show why it isn’t a problem for substantive radical interpretation.

What the construction provides us with are (structurally-rational) candidate interpretations Deviant and Paranoid. Now this was a counterexample to structural radical interpretation, but because we deny that all structurally rational interpretations are substantively rational, they are not (at this point) a counterexample to substantive radical interpretation. However, they still serve generate a challenge: to pin down what constraints of substantive rationality they violate.

Consider the case of a character to whom Deviant would truly apply, who really is agnostic and indifferent about matters outside her local bubble. You might think of her—at least as far as her beliefs are concerned—as someone who read too many classic Cartesian and Humean sceptical arguments and, convinced, ends up suspending judgement on the character of the wider world beyond her local surroundings. This suggests a way of identifying what’s wrong with Deviant. Take your favourite anti-sceptical story about how and why agents are justified in their (standard) beliefs about the world around them, given their evidence. Cite the anti-sceptical story to defend the view that the beliefs attributed by the interpretation Original are justified by the agent’s course of experience, but suspending belief or having paranoid beliefs is not. Then (via a restricted identification of kind 2 above, e.g. that substantive rationality of beliefs coincides with justification) we explain on this basis why Original is more substantively rational than Deviant or Paranoid (all else equal).

To illustrate, suppose the local bubble around an agent encompasses a region of space time varying from a few metres to a several miles (perhaps on occasion, when gazing at the stars, it is much more extensive). We believe that the world outside that bubble—in the region now behind the wall that blocks my view, in the years before I was born and after my death—is similar in character to the world in my bubble. That belief in the spatio-temporal uniformity of nature, across the boundaries of the bubble of my experience and action, is a presupposition of my reasons for holding more specific beliefs, e.g. that the hose I left in the yard yesterday is still there now, that there was some decent popular music recorded in the 1960s, and that pouring chemicals in the local streams will cause environmental damage that will last centuries.  What justification we have for believing that nature is uniform in this way is a familiar, Humean, question, to which first-order epistemology owes us an answer. Perhaps it is this: a belief in the uniformity of nature is the best, simplest explanation of the uniformity that we do see within our local bubble. Add to this the claim that we are justified in believing the best explanation of the phenomenon we observe, and that we are not so justified in believing a worse explanation/no explanation, or in suspending judgement, and we have a epistemic principle we can wield in defence of substantive radical interpretation.

Suppose that the local bubble is more “Cartesian”, including only the agent’s pattern of sense-data and inner volitions—this on the basis that sense-data constitute the sphere of experiential evidence and volitions the sphere of basic action. In that context, we will need to look to epistemology to tell us what justifies ordinary beliefs about the material world around us (insofar as that is not an idealist construct out of sense-data and volitions). We need an answer to what justifies the agent in thinking that there is a solid material chair in which she is sitting, given her evidence consists of a mosaic of colour patches in visual space, pressure patches in bodily space, etc. Andgiventhe starting assumption about the character of basic experiential evidence, then unless the sceptic is going to win, there must be some good answer to it. Perhaps, as Russell thought, inference to the best explanation is again the key. Or perhaps there are simply a priori justified “dogmatic” conditionals, that experience as of a material object so-shaped justifies the belief that there is a material object so-shaped. Having got to the material contents of the local space-time region, we are at the starting blocks of the Humean puzzle just discussed, and by chaining the stories together our first-order anti-sceptical epistemology again is the source of the detailed story about why the bubble puzzle is answered.

It is characteristic of the approach that the necessary first-order epistemology will be a matter of controversy. It is not uncontroversial that justification in the uniformity of nature proceeds by inference to the best explanation. It is not uncontroversial that suspending judgement in the uniformity of nature is unjustified. And even once the operative principles are accepted, there is of course a lot of work to be done in understanding the most foundational epistemic principles on which the epistemic principle operative here—inference to the best explanation—is based. Substantive radical interpretation, for better or worse, simply doesn’t offer many autonomous predictions, independent of the details of first-order epistemic or practical normative theory. But the case of the bubble puzzle, since it’s linked to familiar sceptical scenarios, is a special one, since we are entitled to assume that some anti-sceptical story or other will be forthcoming, and however this plays out, the bubble puzzle will have an answer.

One caveat to the above. An anti-sceptical epistemology is not quite enough. We need an intolerant anti-sceptical epistemology, that is, one that doesn’t simply say that it’s okay (epistemically permissible) to believe in the material world around you and the uniformity of nature, given a standard course of experience, but that such beliefs are epistemically obligatory. Subjective Bayesianism, as an epistemic theory, denies this. They are not classic sceptics, and might even endorse the letter of inference to the best explanation. But for subjective Bayesians, having prior probabilities that favour explanations with such-and-such character in response to a standard course of experience is simply one rational option among many. Sure, our priors are like this, and perhaps there’s a good, non-rational, evolutionary explanation about how we come to be disposed to react to evidence like this. But on this view, there’d be no normative defect in having very deviant priors that favour more complex explanations over simpler ones, and priors that favour e.g. the beliefs attributed by Paranoid, over those attributed by Original. Subjective Bayesians, at least as I’m understanding them here, essentially deny there’s a category of “substantive rationality” in epistemology that can’t be analyzed as the joint upshot of structural rationality constraints plus facts about the priors that are typically shared among creatures like us, but which are not normatively privileged. It is not immediate that the subjective Bayesian reduction of “substantive” rationality would reinstitute the bubble puzzle, since Paranoid and Deviant attribute paranoid and deviant desires as well as beliefs, and one might combine the subjectivist epistemology with a more objectivist account of practical normativity. But I think that’s a faint hope, and we should simply insist that a demanding anti-sceptical epistemology, as opposed to be the permissivist one just sketched, is a presupposition of the project.

This brings us to the end of this initial presentation of my favoured approach to type-2 representation, the grounding of facts about what an agent believes and desires, and to the end of part 1 of my series of posts. As promised, we’ve concentrated on the selectional ideology of “rationalization”. Nothing has been said about the base facts on which the metaphysics of belief/desire is grounded—experience and action. In part 3, I’ll be looking in more detail at the metaphysics of these, more basic, representational facts. Facts about linguistic representation, or other representational artefacts, have not been mentioned. Because of this, the story that has been presented is itself an appropriate basis for going on to theorize those “third-layer” representational facts, and part 4 will cover this. Before all that, though, I want to extract more mileage out of the story of belief and desire than we have seen hitherto, and show the way that this foundational story can predict and explain in a detailed and nuanced way aspects of particular kinds of representational states. Part 2, then, will be deploying the framework I’ve just set out to explain aspects of the way we think about the logically complex, the general, individual objects, and their normative and categorical features.



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