Sunday, May 14, 2006

Levels of Rationality

I'm interested in a certain distinction or conflict between levels of rationality. First, we have the familiar notion which concerns one's immediate evidence, momentary expected utility calculations, and so forth. I would describe it as a kind of 'direct' or 'local' rationality. But on the other hand, it seems we can identify a "higher level" or more encompassing kind of rationality, which steps back or abstracts from one's particular situation, and situates it within a broader strategy or understanding. We might call this 'indirect' or 'global' rationality. I want to explore the way this distinction might shed light on a broad array of philosophical problems. So here's a list of possible applications:

1) Some desirable ends are self-defeating to directly aim at. (This is plausibly true of both happiness and maximizing utility, for example. More obvious "essential byproducts" include spontaneity and sleep.) Because the ends are desirable, direct rationality tells us to aim at them. Indirect rationality suggests we should adopt a different, globally optimal, strategy.

2) Parfit's notion of "rational irrationality" can be made more clearly coherent by noting that it can be globally rational to induce local irrationality in oneself.

3) Applied to epistemic deliberation: local rationality tells us to consider the content alone, and assess each argument or appearance on its merits. Global rationality may invite us to take properties of the source (or 'vehicle') into account. For example, we may reject the evidence of our senses if we've just taken hallucinogenic drugs (or been possessed by the devil), or we might reject an argument on the basis of the speaker's known unreliability. More generally, considerations of 'meta-coherence' concern global rationality. Huemer writes:
I think there’s a rationality constraint roughly to the effect that one’s first-order beliefs (/degrees of belief) should cohere with one’s assessments of how good one’s belief-forming methods are — so if you believe P (to a high degree), you must think that your method of forming that belief is highly reliable (you must also think your belief is justified, undefeated, fully grounded, etc.).

There’s a threat of violating this condition if you assign a higher degree of belief to what seems right to you than to what seems right to person S, while you also hold beliefs that imply that S is more likely to form correct impressions about the matter in question.

Direct rationality leads one to accept "what seems right to you" on the basis of immediate evidence. But global rationality might recommend an indirect strategy of deferring to experts, if that would have globally optimal results for one's pursuit of truth.

4) Regarding Newcomb's problem: Local rationality endorses dominance reasoning at your present moment, and thus recommends taking both boxes. Global rationality again recommends the strategy which will bring you long-term riches, i.e. being a one-boxer.

5) Relatedly, the global rationalist can beat Kavka's toxin puzzle, since they will follow through on their intention to drink the mild toxin even after they've already received the reward.

There are a whole raft of other related problems for local rationality. Consider Quinn's self-torturer (a sort of forced-march sorites paradox), or Pollock's Ever Better wine:
The wine slowly improves with age... More good news: you are immortal. Consequently, you are indifferent as to when you consume a particular good. When should you drink the wine?
    Not now, the wine will be better later.
    Not later. For at any given time it will be true that the wine will be even better if you waited longer.
    But if you do not drink the wine now and do not drink it later, then you will not drink it at all!

-- Roy Sorenson, 'Paradoxes of Rationality' (in The Oxford Handbook of Rationality), p.261.

In such cases, one can only succeed by making resolutions and sticking to them in spite of their local irrationality when the time comes. So that's what global rationality recommends.

Can you think of any other examples of this distinction in action?


  1. Is this not rather like denying them any other piece of information or “making them stupid”?

    Seems to be this is just a matter of how much information you put into your decisions (in this context you seem to propose a person who can't see into the future, or doesn’t care and in the case of sleep knows some rules like "thinking helps" but not others like "thinking too hard makes sleep difficult" so they get nowhere near optimization.

    Also I think you could rationally pick a time to drink the wine (implied by the fact that the story is called "self torturer"

  2. pdf23ds - I was talking about things it is self-defeating to aim directly at (i.e. "focus directly on"). So I needn't deny that one can aim at these things "in a more general sense", if by that you simply mean "pick a global strategy that will achieve it". There's still the distinction between direct and indirect "aiming" here.

    G. - the "self-torturer" is a different example, you can follow the link for details. But in case of Ever Better Wine, suppose the day you pick has arrived. Should you drink it now? Well, local rationality says no: it will be better if you wait for tomorrow. To stick by global resolutions, one needs to be willing to act in ways that will seem (locally) irrational, or sub-optimal at the time.

  3. Hmm well to me using only "local knowledge" is a pretty foreign concept.

    > But in case of Ever Better Wine, suppose the day you pick has arrived. Should you drink it now?

    Maybe we shouldn’t use the word "you" because the person in question needs to be a pretty stripped down human - amongst other things - one who doesn’t have diminishing value of future events.

    I'm also wondering why local rationality means you don’t drink it as opposed to just drinking it. It seems to vary according to what facts get defined as "local" is there a way of defining what facts are "local" and when things are "global"?

    Also I am not sure you can say "you won't drink it at all" that implies an assertion about a function of infinity.

  4. This is a slightly irrelevant comment, and it is concerned with the general practice of dividing up into parts concepts that we usually regard, through instinct or prejudice or good sense, as indivisible. Another example of the usefulness of this technique is, I think, the response to the Meno paradox that proceeds by recognising that concepts in general are just as likely to be made up of parts as any other thing. If we do this, we are less inclined to ask, like Meno, "how will you look for something when you don't the least know what it is...since even if you come right up against it, how will you know what you have found is the thing you didn't know?" To elaborate: this is at least partly resolved if we remember that objects are made up of lots of different properties, and so we can not know what some object is (we only know some of its properties), and yet still be able to find it, and find out more about it (since the few properties we know may be enough to uniquely identify the object in question).

    This process of innovative division may also be applied, I think, to the following argument: "Philosophy is immune to criticism, since to criticise philosophy is to make a philosophical claim." Suppose that we recognise a number of different parts to this thing we call "Philosophy": perhaps some arise because there are many different topics in philosophy, and others arise because there are different degrees to which one may pursue Philosophy, and because one may do so at different times of day or of life. Recognising that, we see that it is plausible for a person to criticise vast tracts of Philosophy without any incoherence, provided their criticism does not entail their participation in the part of Philosophy they are criticising. It is true that noone can coherently criticise all of Philosophy, but this is very moderate claim, and perhaps not a claim that anyone has ever seriously entertained.


Visitors: check my comments policy first.
Non-Blogger users: If the comment form isn't working for you, email me your comment and I can post it on your behalf. (If your comment is too long, first try breaking it into two parts.)

Note: only a member of this blog may post a comment.