[I wrote the following in an exam for Michael Smith's class last semester. It explains some helpful distinctions that I want to be able to refer back to in future posts...]
In 'Reasons: Practical and Adaptive' Raz makes distinctions between, on the one hand, practical and adaptive reasons, and on the other, standard and non-standard reasons. Explain these distinctions using examples.
Imagine a biology student whose parents threaten to disown her should she ever come to believe in evolution. This situation exposes her to what look to be two very different kinds of reasons regarding her belief. From her biology class, the student receives epistemic reasons, i.e. reasons which speak to the truth of the thing believed. From her parents, she receives practical reasons, i.e. reasons which speak to the (dis)value of holding the belief in question. There are a couple of noteworthy differences revealed by this scenario, which form the bases of Raz’s two distinctions.
First, consider how reflecting on the various reasons will affect the student’s beliefs. Faced with compelling evidence that evolution has in fact occurred, she may - as a rational agent - come to believe it. That is, her rational faculties may respond to her apprehension of epistemic reasons for a belief by directly producing the recommended belief. This marks epistemic reasons as instances of what Raz calls standard reasons, or reasons that “we can follow directly”. Practical reasons for belief, by contrast, are non-standard in that they cannot be directly followed. Much as the student might wish to please her parents, no amount of reflection on their threat will suffice by itself to change her scientific beliefs.
What if people could respond directly to practical reasons for belief by changing their belief? It seems like this should be possible. At least, we can imagine a scenario in which reflecting on the practical benefits of holding a belief has a similar neurological effect as what actually happens when we reflect on evidence suggesting the truth of a belief. One might argue that the resulting neurological state, being sensitive to non-epistemic reasons, no longer qualifies as ‘belief’. But this seems implausible so long as enough of the functional role of belief remains intact: the person still sincerely asserts the proposition when asked what they believe, draws inferences from it, and behaves in ways that could be expected to fulfill their desires if the proposition were true, etc. So I think we must allow that this scenario is properly described as involving belief. But does it involve following a reason? This seems more questionable. Raz suggests, of a similar case, that the agent merely deceives themselves into believing that they followed the reason. They have not really done so, for that would be impossible -- it is not the kind of reason that can genuinely be followed in such a fashion. Of course, to assert this without argument risks begging the question, as Raz well recognizes. What we need is some independent basis for determining which reasons can be followed and hence qualify as standard reasons.
One thing we can tell right away is that this is not simply an empirical matter, to be ‘read off’ the neuro-psychological data. Not all forms of influence qualify as rational influence, and information may make its way into our heads without doing so under the guise of a reason. The other lesson from the above scenario is that, as Raz puts it, “whether one follows a reason is not purely a matter of how the agent understands his situation.” Combining these: the agent may cite a practical reason why he holds his belief, and it may indeed have played a central causal role in his neuro-psychology, but this still does not count as following the practical reason, in the normative sense we’re interested in here.
But why not? Raz appeals to “the nature of that reason” to settle the matter. This works most clearly in the case of reasons that are such that it would be self-defeating to try to follow them. For example, I may offer you $100 to hop on one leg for non-pecuniary motives. The prize-money is a reason to hop, but not one you could follow directly without thereby disqualifying yourself. The self-effacing nature of the reason is a logical fact which explains why it cannot be successfully followed, and thus why it is non-standard. But the previous case of practical reasons for belief is less clear. Raz claims that “the fact that non-epistemic reasons cannot serve to warrant belief shows that they cannot be followed.” It is not entirely transparent why this should be so. But I think it is most plausibly understood in reference to the normative character of reason-following, where this is taken to essentially involve a response on the part of our rational faculties (rather than just any old psychological process). Standard reasons are thus understood to be those that rationally justify or warrant the attitude they recommend. Or, if we are willing to take rationality itself as a primitive: standard reasons are those that our rational capacities respond to (insofar as they are functioning properly). Of course, even non-standard reasons may be rationally responded to in a different way: they warrant acting so as to bring about their target attitude, for example. This confirms Raz’s point that non-standard reasons for one thing are standard reasons for something else.
(Aside: there may be some exceptions to this claim. Suppose that God will reward those who are saintly, but to qualify as a saint you must never act from self-interest. This sounds a lot like the other non-standard reasons we’ve discussed, so it would seem ad hoc to deny that it really is a reason. But it cannot be redescribed as a standard reason for anything. However indirectly you bring about your sainthood, if you do it for the reason of the heavenly reward, then you’re no saint after all. So this looks like a non-standard reason without any corresponding standard reason. To hold onto his view that “the fact that they can be followed is what makes reasons into reasons”, Raz had best deny that “non-standard reasons” are really reasons at all. There are no practical reasons for belief. There are just standard reasons for acting to bring about a belief.)
So much for Raz’s first distinction. What of the second? Harking back to our original case of the biology student, notice that only her practical reasons derived from the value of holding the belief. Epistemic reasons instead indicate that the belief would be warranted or appropriate to the way things are, but this does not depend on whether believing the truth would be in any way beneficial. This renders epistemic reasons a subset of what Raz calls adaptive reasons. The adaptive/practical distinction arises whenever we have states whose internal norms of correctness may diverge from their practical value. Emotions are another obvious example. Given that fear is meant to be a response to danger, evidence that we are in danger provides an adaptive reason for this emotion; fear is warranted in such circumstances, regardless of whether it would be beneficial (a question which instead concerns the practical reasons for and against it).
Raz offers what we may take to be three tests for the dependence of reasons on value: (i) the possibility of akrasia, (ii) shaping the world to fit the attitude, and (iii) presumptive sufficiency. Here I will discuss only the second, as it is most vivid. If there’s value in the state of affairs of your having warranted attitudes, then this should be so whether this state of affairs came about as a result of shifting your attitudes to match the world, or by changing the world to match your attitudes. But this is absurd: if you feel fear, for example, there is nothing at all to be said for manipulating your situation to match your emotion by gratuitously exposing yourself to danger. Danger is a reason for fear, but fear is not a reason for (bringing about) danger. This asymmetry demonstrates that the reasons we have for feeling fear when in danger are adaptive reasons -- they do not assume that there is necessarily value in the combination of fear and danger.
Now that I have introduced Raz’s two distinctions, one might wonder about the degree to which they overlap. From my original example, we saw that epistemic reasons are standard and adaptive, whereas the non-epistemic reasons for belief are non-standard and practical. But not all standard reasons are adaptive reasons: sometimes warrant derives from value, as we find for example in reasons for action. If leaping into the air would produce great benefits, then I may follow this reason and rationally decide to leap. So that is an example of a standard practical reason. There may also be non-standard reasons for action, as we saw earlier in the case of prize money given to those who hop from non-pecuniary motives. (Note that this would also be a standard reason to bring it about that you hop, say by stabbing yourself in the foot. The latter is a reason you can follow without self-defeation.)
There is at least some overlap between the two distinctions, however, for there is no possibility of a non-standard adaptive reason. Non-standard reasons for an attitude are really just standard reasons for bringing about the attitude, and this places them firmly in the practical domain. We have seen that the other combinations are all possible, however:
(i) standard adaptive reasons, e.g. scientific evidence as a reason for belief, or evidence of danger as a reason for fear;
(ii) standard practical reasons, e.g. ordinary monetary rewards as a reason for action;
(iii) non-standard practical reasons, e.g. self-effacing rewards as a reason for action, or threat of parental disownment as a reason for belief.
Tuesday, April 08, 2008
Standard Reasons, Adaptive Reasons
Saturday, December 02, 2006
Writing Sample: Global Rationality
[Here's the writing sample I'm using for my grad school applications. It's a revised version of an earlier draft I once posted here.] Introduction We typically conceive of rationality in atomistic terms, as a matter of doing what seems best from the local perspective of the moment, or maximizing expected utility. I want to explore an alternative – more holistic – way of thinking about rationality, which applies primarily at the global level of the whole, temporally extended person, in contrast to the local level of each momentary person-stage. This distinction may be motivated by noting that global optimality can – for various reasons – require us to do other than what seems optimal within the confines of a moment. Holistic rationality, as I envisage it, tells us to adopt a broader view, transcending the boundaries of the present and identifying with a timeless perspective instead. Of course, even atomists will want to go beyond the present by including knowledge about the future in their decision procedure. But I wish to make the stronger claim that the procedure itself should be, in an important sense, time-invariant. We might think of this as a kind of universalization constraint: to assess a decision procedure or form of practical reasoning, you should consider the consequences, not just of employing it at this momentary stage, but at all your relevantly similar stages. Julian Nida-Rumelin has suggested: “It is perfectly rational to refrain from point-wise optimization because you do not wish to live the life which would result.”1 Yet refraining from optimization might seem to violate the principle that one rationally ought to do what seems best. To reap the rewards of global rationality, we must be willing to treat the dictates of the broader perspective as rationally authoritative, no matter how disadvantageous it may seem from the particular perspective of our local moment.2 This amounts to an intrapersonal analogue of the ‘social contract’: each of our momentary stages abdicates some degree of rational autonomy, in order to enhance the rationality and autonomy of our person as a whole. The challenge here is to make sense of the normative status of the advice issuing from these conflicting perspectives. What, for instance, should consequentialists say about those particular instances in which following the globally optimal strategy would actually have worse consequences? I will draw on – and further develop – the theoretical apparatus of contemporary philosophy of normativity in order to diagnose, clarify, and assess the various ways such conflicts may arise, and to rebuff charges of inconsistency or paradox. Overall, this essay seeks to establish two things. First, the distinction between local and global levels of rationality can be fruitfully applied, as an extension of the standard framework, to help us understand the puzzles discussed by Parfit and others. Secondly, we would do well to favour the global level in cases where the two conflict. First, let us distinguish the objective and subjective modes of normativity, as reflected in contemporary philosophical use of the terms ‘reasons’ and ‘rationality’.3 Reasons are provided by facts that count in favour of an action. For example, if a large rock is about to hit the back of your head, then this is a reason for you to duck, even if you are unaware of it. As this example suggests, the objective notion I have in mind is largely independent of our beliefs: p can be a reason for you, in this sense, even if you do not believe that p.4 As inquiring agents, we try to discover what reasons for action we have in virtue of our actual situation, and hence what we should do. Such inquiry would be redundant according to subjective accounts, which restrict reasons to things that an agent already believes. So I use the term exclusively in its objective sense. Consequentialism implies that we have reason to bring about good states of affairs, and to prevent bad ones from obtaining.5 I take it as analytic that we have most reason to do what would be best. I will follow Parfit’s terminology in saying that this is what one ought, in the reason-implying sense, to do.6 There is another sense of ‘ought’, tied to the subjective or evidence-based notion of rationality rather than the objective or fact-based notion of ‘reasons’. As Kolodny puts it, rationality is “about the relation between your attitudes, viewed in abstraction from the reasons for them.”7 Sometimes the evidence can be misleading, so that what seems best is not really so. In such cases, we may say that one rationally ought to do what seems best, given the available evidence. But due to their ignorance of the facts, they would not be doing what they actually have most reason to do. Though they couldn’t know it, some alternative action would have been better. This raises the question of what to say when reasons and rationality diverge. Suppose that someone ought, in the reason-implying sense, to X, but that they rationally ought to Y. If innocent people have been convincingly framed, for instance, then the (unknown) facts provide reasons for acquittal, though it may be rational for a jury to condemn them based on the available evidence. Which takes precedence? What is it that the jury really ought to do? There is some risk of turning this into a merely terminological dispute. But we can make some substantive observations here. In particular, I think that the reason-involving sense of ‘ought’ is arguably the more fundamental normative concept. This is because it indicates the deeper goal, or what agents are ultimately seeking. The purpose of deliberation is to identify the best choice, or reach the correct conclusion. In practice, we do this by settling on what seems to us to be best. But we do not think that the appearances have any independent force, over and above the objective facts. We seek to perform the best action, not merely the best-seeming one. Of course, from our first-personal perspective we cannot tell the two apart. That which seems best to us is what we take to truly be best. Belief is, in this sense, “transparent to truth”. Because our beliefs all seem true to us, the rational choice will always seem to us to also be the best one.8 We can thus take ourselves to be complying with the demands of both rationality and fact-based reasons. Nevertheless, it is the latter that we really care about. One way to bring this out is to consider the advice that would be given by a helpful third party: recognizing your false beliefs, they would surely advise you to do what was truly best, rather than what merely seemed to you to be so.9 This is especially clear in epistemology. We seek true beliefs, not justified ones. Sure, we would usually take ourselves to be going wrong if our beliefs conflicted with the available evidence. Such conflict would indicate that our beliefs were likely false. But note that it is the falsity, and not the mere indication thereof, that we are ultimately concerned with. More generally, for any given goal, we will be interested in evidence that suggests to us how to attain the goal. We will tend to be guided by such evidence. But this does not make following the evidence itself our ultimate goal. Ends and evidence are intimately connected, but non-identical. Normative significance accrues in the first instance to our ends, whereas evidence is merely a means: we follow it for the sake of the end, which we know not how else to achieve. Applied to the particular case of reasons and rationality, then, it becomes clear that reasons are closer to the real goal, whereas rationality is merely the guiding process by which we hope to achieve it. Since arriving at the intended destination is ultimately more important than faithfully following the guide, we may conclude that the reason-implying sense of ‘ought’ takes normative precedence.10 I will use this as my default sense of ‘ought’ in what follows. Indirect Utilitarianism and Blameless Wrongdoing Act Utilitarianism claims that our actions ought to maximize the good. Paradoxically, if people tried to act like utilitarians, this would plausibly have very bad consequences. For example, authorities would engage in torture or frame innocent persons whenever they believed that doing so would cause more good than harm. Such beliefs might often be mistaken, however, and with disastrous consequences. Let us suppose that attempts to directly maximize utility will generally backfire. Utilitarianism then seems to imply that it is wrong to be a utilitarian. But the conclusion that utilitarianism is self-defeating only follows if we fail to distinguish between criteria of rightness and decision procedures.11 We typically conceive of ethics as a practically oriented field: a good moral theory should be action-guiding, or tell us how to act. So when utilitarianism claims that the right action is that which maximizes utility, it is natural for us to read this as saying that we should try to maximize utility. But utilitarianism as defined above does not claim that we ought to try to maximize utility. Rather, it claims that we should achieve this end. If one were to try and fail, then their action would be wrong, according to the act-utilitarian criterion. This seems to be in tension with the general principle that we rationally ought to aim at the good. The utilitarian criterion instead tells us to have whatever aims would be most successful at attaining the good. This difference will be clarified in the section on ‘object- and state-based modes of assessment’, later in this essay. For now, simply note that the best utilitarian consequences might result, say, from a steadfast commitment to respect human rights no matter how expedient their violation might appear. In this case, the utilitarian criterion tells us that we should inculcate such anti-utilitarian practical commitments. This indicates a distinction between two levels of normative moral thought: the intuitive and the critical.12 Our intuitive-level morality consists of those principles and commitments that guide us in our everyday moral thinking and engage our moral emotions. This provides our moral decision procedure. It is often enough to note that an action would violate our commitment to honesty, for instance, to settle the question of whether we should perform it. This is not the place for cold calculation of expected utilities. They instead belong on the critical level, when it comes time to determine which of our intuitive principles and commitments are well-justified ones. For the indirect utilitarian, honesty is good because being honest will do a better job of improving the world than would being a scheming, opportunistic, direct utilitarian. The general picture on offer is this: we use utility as a higher-order criterion for picking out the best practical morality, and then we live according to the latter. Maximizing utility is the ultimate goal, but we do well to adopt a more reliable indirect strategy – and even other first-order “goals” – in order to achieve it.13 What shall we say of those situations where the goal and the strategy conflict? Consider a rare case where, say, framing an innocent person really would have the best consequences. Such an act would then be right – or what we have most reason to do – according to the utilitarian criterion. Yet our practical morality advises most strongly against it, and ex hypothesi we ought to live according to those principles. Does this imply a contradiction: the right action ought not to be done? Only if we assume a further principle of normative transmission: (T) If you ought to accept a strategy S, and S tells you to X, then you ought to X.14 This is plausible for the rational sense of ‘ought’, but not the reason-involving sense that I am using here. We might have most reason to adopt a strategy – because it will more likely see us right than any available alternative – without thereby implying that the strategy is perfect, i.e. that everything it prescribes really is the objectively best option. S might on occasion be misleading, and then we could have more reason to not do X, though we remain unaware of this fact. So we should reject (T), and accept the previously described scenario as consistent. To follow practical morality in such a case, and refrain from expedient injustice, would constitute what Parfit calls “blameless wrongdoing”.15 The agent fails to do what they have most moral reason to do, so the act is wrong (objectively suboptimal). But the agent herself has the best possible motives and dispositions, and could say, “Since this is so, when I do act wrongly in this way, I need not regard myself as morally bad.”16 Parfit’s solution may be clarified by appealing to my earlier distinction between the local and global levels. Our ‘local’ assessment looks at the particular act, and condemns it for sub-optimality. The ‘global’ perspective considers the agent as a whole, with particular concern for the long-term outcomes obtained by consistent application of any given decision-procedure. From this perspective, the agent is (ex hypothesi) entirely praiseworthy: their psychological makeup will in fact lead to better consequences overall than any available alternative.17 The apparently conflicting judgments are consistent because they are made in relation to different standards or modes of assessment. I have illustrated this with the example of indirect utilitarianism, but the general principle will apply whenever some end is best achieved by indirect means. More generally than “blameless wrongdoing”, we will have various forms of (globally) optimal (local) sub-optimality. Meta-coherence and Essential By-products The above discussion focused on the objective, reason-involving sense of ‘ought’. Let us now consider the problem in terms of evidence and what one rationally ought to do. Rationality demands that we aim at the good, or do what seems best, i.e. maximize expected utility. But the whole idea of the indirect strategy is to be guided by reliable rules rather than direct utility calculations. One effectively commits to occasionally acting “irrationally” (in the local sense), though it is rational – subjectively optimal – to make this commitment. Parfit thus calls it “rational irrationality”.18 But we may question whether expected utility could really diverge from the reliable rules after all. Sometimes we may be in a position to realize that our initial judgments should be revised. I may initially be taken in by a visual illusion, and falsely believe that the two lines I see are of different lengths. Learning how the illusion worked would undercut the evidence of my senses. I would come to see that the prima facie evidence was misleading, and the belief I formed on its basis likely false. Principles of meta-coherence suggest that it would be irrational to continue accepting the appearances after learning them to be deceptive, or more generally to hold a belief concurrently with the meta-belief that the former is unjustified or otherwise likely false.19 This principle has important application to our current discussion, potentially unifying the two levels of local and global rationality. We adopt the indirect strategy precisely because we recognize that our direct first-order calculations are unreliable. The utilitarian sheriff might think that framing an innocent subject would have high expected utility. But if he recalls his own unreliability on such matters, he should lower the expected utility accordingly. As a good indirect utilitarian, he believes that in situations subjectively indiscernible from his own, to follow a strict policy of never framing innocent persons will generally yield the best results. Taking this higher-order information into account, he should revise his earlier judgment and instead reach the all-things-considered conclusion that seeing justice done maximizes expected utility even for this particular act.20 This seems to collapse the distinction between local and global rationality. When all things are considered, the former will come to conform to the latter.21 This will not always be the case, however. A crucial feature of the present example is that one can consciously recognize the ultimate goal at the back of their mind, even as they employ an indirect strategy in its pursuit. But what if the pursuit of some good requires that we make ourselves more thoroughly insensitive to it? Jon Elster calls such goods “essential byproducts”, and examples might include spontaneity, sleep, acting unselfconsciously, and other such mental absences.22 Such goods are not always susceptible to momentary rational pursuit, even with indirect strategies. The problem is no longer mere ignorance of how best to achieve the good. Rather, to achieve these goods we must relinquish any conscious intention of doing so. As we relax and drift off to sleep, we cannot concurrently conceive of our mental inactivity as a means to this end. One cannot achieve a mental absence by having it “in mind” in the way required for the means-ends reasoning I take to be constitutive of rationality. In the event of succeeding, one could no longer be locally rational in their pursuit of the essential byproduct, for they would not at that moment be intentionally pursuing it at all. Nevertheless, there remains an important sense in which a person remains perfectly rational in having their momentary selves abdicate deliberate pursuit of these ends. If we attribute the goal of nightly sleep to the whole temporally extended person, then this abdication is precisely what sensible pursuit of the goal entails. In this sense, we can understand the whole person as acting deliberately even when their momentary self does not. So the distinction is upheld: global rationality recommends that we simply give up on trying to remain locally rational when we want to get some rest. Object- and State-based modes of assessment Odd as it may seem, even local rationality recommends surrendering itself in such circumstances. From the local perspective of the moment, pursuit of the goal is best advanced by ensuring that one’s future self refrains from such deliberate pursuit. The puzzle arises because mental states are subject to two very different modes of assessment: one focusing on the object of the mental state, and the other focusing on the state itself.23 Suppose an eccentric billionaire offers you a million dollars to believe that the world is flat. The object of belief, i.e. the proposition that the world is flat, does not merit belief. But this state of belief would, in such a case, be a worthwhile one to have. In this sense we might think there are reasons for (having the state of) believing, which are not reasons for (the truth of) the thing believed.24 It seems plausible that desire aims at value in much the same way that belief aims at truth. Hence, indications of value could provide object-based reasons for intention or desire – much as indications of truth provide object-based reasons for belief – whereas the utility of having the desire in question could provide state-based reasons for it.25 This is the difference between an object’s being worthy of desire, and a desire for the object being a state worth having. There are various theories about what reasons we have for acting, and hence what objects merit our pursuit. For example, we may call “Instrumentalism” the claim that we have reason to fulfill our own present desires, whatever they may be. Egoism claims that we have most reason to advance our own self-interest. And Impartialism says that we have equal reason to advance each person’s interests. I propose that for any such account of reasons, we can pair it with a corresponding account of object-based local rationality, based on the following general schema: (G) Rationality is a matter of pursuing the good, i.e. being moved by the appearance of those facts ____ that provide us with reasons for action. Let us say that S has a quasi-reason to X, on the basis of some non-normative proposition p, when the following two conditions are satisfied: (i) S believes that p; and (ii) if p were true then this would provide a reason for S to X. Note that on my above account, S need not recognize that the truth of p would provide reason to X. We may then understand (G) as the claim that one rationally ought to do what one has most quasi-reason to do. This clarifies the proposed relation between reasons and rationality, as distinct from an alternative view that holds simply that one is rationally required to do whatever they believe they have most reason to do. The different theories mentioned earlier posit different reasons, so different quasi-reasons, and hence different specifications of rationality in this sense. For example, according to Egoism, agents are rational insofar as they seek to advance their own interests. There is a sense in which the theory thereby claims this to be the supremely rational aim.26 But let us suppose that having self interest as one’s dominant local aim would foreseeably cause one’s life to go worse, as per “the paradox of hedonism”.27 Egoism then implies that we would be irrational to knowingly harm ourselves by having this aim. This conclusion seems to contradict the original claim that this aim is “supremely rational”. On this basis, Dancy claims that such theories are flatly inconsistent: they “say… that there is a single rational aim which it is not rational… to aim at.”28 The distinction between object- and state-based assessments may help resolve this problem. We might say that an aim embodies rationality in virtue of its object, in that it constitutes supreme sensitivity to one’s quasi-reasons. Or the aim might be recommended by rationality, in the sense that one’s quasi-reasons tell one to have this aim, in virtue of the mental state itself. As before, the apparent incoherence can be traced to the conflation of two distinct modes of assessment. The aforementioned theories should be interpreted as claiming that their associated aims supremely embody rationality, even though it might not be rationally recommended to embody it so. This reflects the coherent possibility that something might be desirable – worthy of desire – even if the desire itself would, for extrinsic reasons, be a bad state to have. It is worth noting that this distinction appears to hold independently of the local/global distinction. We might imagine a good – perhaps sainthood29 – that would be denied to anyone who ever entertained it as a goal. If one sought it via the standard “globally rational” method of preventing one’s future momentary selves from deliberate “locally rational” pursuit, it would already be too late: this initial plotting would suffice to disqualify one. There is no rational way at all, on any level, to pursue the good. Still, being of value, the good might merit pursuit. It might even provide reasons of sorts, even though one could never recognize them as such.30 So although the object/state distinction may recommend a shift from local to global rationality, it further establishes that even the latter may, in special circumstances, be transparently disadvantageous. Reasons and rationality may come apart, even when no ignorance is involved, because it may be best to achieve a good without ever recognizing it as such. This would provide reasons that elude our rational grasp, being such that we ought to act unwittingly rather than by grasping the reason that underlies this very ‘ought’-fact. Rational Holism We have seen how various distinctions, including that between the local and global levels of rationality, can help us to make sense of the indirect pursuit of goods. If we know our first-order judgments to be unreliable, then meta-coherence will lead us to be skeptical of those judgments. Indirect utilitarianism stems from recognizing that expected utility is better served by instead following a more reliable – globally optimal – strategy, even if this at times conflicts with our first-order judgments of expedience. Global rationality paves the way for utilitarian respect for rights, and meta-coherence carries it over to the local level. Essential by-products re-establish the distinction, as we may understand a goal as being rationally pursued at the level of the temporally extended person, if not at the level of every momentary stage or temporal part. Although the object/state distinction implies that even global rationality may be imperfect, the preceding cases suggest that we would do well at least to prize the global perspective over the local one. I now want to support this conclusion by considering a further class of problems that could be fruitfully analyzed as pitting the unified agent against their momentary selves. Consider Newcomb’s Problem:31 a highly reliable predictor presents you with two boxes, one containing $1000, and the other with contents unknown. You are offered the choice of either taking both boxes, or else just the unknown one. You are told that the predictor will have put $1,000,000 in the opaque box if she earlier predicted you would pick only that; otherwise she will have left it empty. Either way, the contents are now fixed. Should you take one box or both? From the local, momentary perspective, the answer seems clear: the contents are fixed, it’s too late to change them now, so you might as well take both. Granted, one would do better to be the sort of person who would pick only one box. That is the rationally recommended dispositional state. But taking both is the choice that embodies rationality, according to the local view. This atomistic reasoning predictably leads to a mere $1000 prize. Suppose that one instead adopted a more holistic perspective, giving weight to the kinds of reasoning that, judging from the timeless perspective, one would want one’s momentary stages to employ. This globally rational agent is willing to commit to being a one-boxer, and so will make that choice even when it seems locally suboptimal. This predictably leads to the $1,000,000 prize, which was unattainable to the atomist. Similar remarks apply to Kavka’s toxin puzzle.32 Suppose that you would be immediately rewarded upon forming the intention to later drink a mild toxin that would cause you some discomfort. Since you will already have received your reward by then, there would seem no narrowly local reason for you to carry out such an intention. Recognizing this, an atomist about rationality cannot even form the intention to begin with. (You cannot intend to do something that you know you will not do.) Again we find that atomistic reasoning disqualifies one from attaining something of value. The rational holist, by contrast, is willing to follow through on earlier commitments even in the absence of temporally local reasons.33 She wishes to be the kind of person who can reap such rewards, so global rationality leads her to behave accordingly. In both these cases, the benefits of global rationality require that one be disposed to follow through on past commitments. One must tend to recognize one’s past reasons as also providing reasons for one’s present self. This allows one to overcome problems, such as the above, which are based on a localized object/state distinction.34 But occasional violation of this disposition might allow one to receive the benefits without the associated cost. (One might receive the reward for forming the sincere intention to drink the toxin, only to later surprise oneself by refusing to drink it after all.) So let us now consider an even stronger sort of case that goes beyond the object/state distinction and hence demands more than the mere disposition of global rationality. Instead, the benefits will accrue only to those who follow through on their earlier resolutions.35 Pollock’s Ever Better Wine improves with age, without limit.36 Suppose you possess a bottle, and are immortal. When should you drink the wine? Atomists could never drink it, for at any given time they would do better to postpone it another day. But to never drink it at all is the worst possible result! Or consider Quinn’s Self-Torturer, who receives $10,000 each time he increases his pain level by an indiscernible increment.37 It sounds like a deal worth taking. But suppose that the combined effect of a thousand increments would leave him in such agony that no amount of money could compensate. Because each individual increment is – from the narrowly local perspective of the moment – worth taking, rational atomism will again lead one to the worst possible result. A good result is only possible for agents who are willing to let their global perspective override local calculations. The agent must make in advance a rational resolution to stop at some stage n, even though from the local perspective of stage n he would do better to continue on to stage n+1. It seems clear that the global perspective is rationally superior. The agent can foresee the outcomes of her possible choices. If she endorses the local mode of reasoning then she will never have grounds to stop, and so will end up stuck with the worst possible outcome. It cannot be rational to accept this when other options are open to her. If she is instead resolute and holds firm to the choice – made from a global or timeless perspective – to stop at stage n, then she will do much better. Yet one might object that this merely pushes the problem back a step: how could one rationally resolve to choose n rather than n+1 in the first place? The problem of Buridan’s ass, caught between two equally tempting piles of hay, shows that rational agents must be capable of making arbitrary decisions.38 It cannot be rational for the indecisive ass to starve to death in its search for the perfect decision. Indeed, once cognitive costs are taken into account, it becomes clear that all-things-considered expected utility is better served by first-order satisficing than attempted optimizing.39 (“The perfect is the enemy of the good,” as the saying goes.) Applying this to the above cases, we should settle on some n, any n, that is good enough. Once we have made such a resolution, we can reject the challenge, “why not n+1?” by noting that if we were to grant that increment then we would have no basis to reject the next ones, ad infinitum, and that would lead us to the worst outcome. Though our reasoning activity takes place at particular moments, the perspective we adopt at that time need not be so limited. We can, in the present, reason as if from a global perspective – and the above cases suggest that this is precisely what we rationally ought to do. Hence I propose the following negative principle of rational holism: (H-) In any given situation: one rationally ought not to employ any decision procedure that could not be endorsed from a global perspective (i.e. abstracting away from one’s present temporal location or momentary stage). The above discussion shows that point-wise optimization is not temporally universalizable in some cases. If one endorses the arbitrary shift from n to n+1, parity of reasoning would lead one’s future selves to never stop. The consequences of universalizing that method of reasoning would be clearly undesirable, so (H-) requires us to reject it. The atomist’s “local rationality” is in fact not rational at all. Instead, the way we should reason at a moment derives from the methods we would endorse from a timeless perspective. Of course, in unproblematic cases, the locally optimal option may happen to coincide with what is truly (globally) rational. Our idealized timeless selves might endorse our present use of the decision procedure. But as the diverging cases show, it is the global perspective that takes precedence. Hence the positive holistic principle: (H+) In any given situation: one rationally ought to act and reason as one would recommend from a timeless perspective. It is not enough simply to determine that n+1 is better than n, and hence take that step before determining what to do next. In cases where local and global optimality diverge, one must instead look at the “big picture”, resolve where one wants to end up, and act accordingly. Of course, in reality our reasoning always takes place within a specific temporal context. But we may nevertheless adopt a timeless perspective by abstracting away such details, and thus refusing to employ methods of reasoning that we recognize as non-universalizable. Thus localized decisions may be governed by global norms. Conclusion The standard picture of rationality is thoroughly atomistic. It views agents as momentary entities, purely forward-looking from their localized temporal perspective. In this essay, I have presented an alternative, more holistic view. I propose that we ascribe agency primarily to the whole temporally extended person, rather than to each stage in isolation. This view allows us to make sense of the rational pursuit of essential by-products, as we may ascribe deliberate purpose to a whole person even if it is absent from the minds of some individual stages. Moreover, global rationality sheds light on the insights of indirect utilitarianism, though meta-coherence allows that these conclusions may also be accessible from a temporally localized perspective. I have shown how to develop Parfit’s framework to better accommodate these puzzling cases, in response to charges of outright inconsistency. Finally, I have argued that there are cases where reasoning in the atomistic manner of point-wise optimization leads to disaster. Such disaster can be avoided if the agents embrace my holistic conception of rational agency, acting only in ways that they could endorse from a global or timeless perspective. Persons are more than the sum of their isolated temporal parts; if we start acting like it then we may do better than traditional decision theorists would think rationally possible. 1 Nida-Rumelin, p.13. 2 Harsanyi, p.122, seems to be getting at a similar idea in his discussion of the “normal mode” of playing a game. 3 See, e.g., Kolodny, pp. 509-510, and Parfit (ms.), p.21. 4 Of course we can imagine special circumstances whereby one’s holding of a belief would itself be the reason-giving ‘fact’ in question. If I am sworn to honesty, then the fact that I believe that P may itself provide a reason for me to assert that P. 5 I leave open the question whether such value is impersonal or agent-relative. 6 Parfit (ms), p.21. I also follow Parfit’s use of the term “rationally ought”, below. 7 Kolodny, p.509, italics omitted. 8 Cf. Kolodny’s “transparency account” of rationality’s apparent normativity (p.513). 9 I owe this idea to Clayton Littlejohn. 10 Of course, the agent may not know of any more reliable option than to follow the guide. As noted above, we must move beyond the first person perspective before this distinction will seem significant. 11 This is a familiar distinction, see e.g. the Stanford Encyclopedia entry on ‘Rule Consequentialism’, http://plato.stanford.edu/entries/consequentialism-rule/#4 [accessed 21/6/06]. 12 The following is strongly influenced by R.M. Hare. 13 Hare, p.38. This is distinct from “rule utilitarianism”, which I take to be the claim that whatever the rules advise is ipso facto what we ought to do. The example below should make the difference clearer. 14 This is a generalization of the sorts of transmission principles that Parfit (1987) rejects. 15 Parfit (1987), pp.31-35. Cf. my section on ‘meta-coherence’ below, where I argue that this is not really “wrongdoing” at all from the perspective of subjective rationality. However, the current section is concerned with the objective, fact-based sense of ‘ought’, independent of what the agent happens to know. 16 Ibid., p.32. (N.B. Here I quote the words that Parfit attributes to his fictional agent ‘Clare’.) 17 This arguably means that the so-called “locally optimal” action isn’t optimal at all: the closest possible world where the agent so acts is a worse world overall, because in that world she acts worse in other situations. But this raises complicated issues about the appropriate comparison class for the relevant counterfactuals, which goes beyond the scope of this essay. See Dancy, pp.9-10. 18 Parfit (1987), p.13. Though the more radical (non-epistemic) cases he discusses are better covered by my treatment of “essential byproducts” below. 19 I owe the idea of “meta-coherence” to Michael Huemer. 20 Of course, an injustice might in fact yield the best results. But this section is discussing the evidential question, i.e. expected, rather than actual, utility. 21 Two further points bear mentioning: (1) We might construct a new distinction in this vicinity, between prima facie and all things considered judgments, where the former allows only first-order evidence, and the latter includes meta-beliefs about reliability and such. This bears some relation to ‘local’ vs. ‘global’ considerations, and again I think the latter deserves to be more widely recognized. Nevertheless, I take it to be distinct from the “momentary act vs. temporally-extended agent” form of the local/global distinction, which this essay is concerned with. (2) Even though a meta-coherent local calculation should ultimately reinforce the indirect strategy, that’s not to say that one should actually carry out such a decision procedure. The idea of indirect utilitarianism is instead that one acts on the dispositions recommended by our practical morality, rather than having one “always undertake a distinctively consequentialist deliberation” [Railton, p.166]. So my local/global distinction could do some work here after all, in the manner described below. 22 Elster, pp.43-52. 23 Cf. Parfit (ms), p.30. 24 Musgrave, p.21. 25 This evidence-based notion is another common use of the term “reasons”. But in light of my earlier remarks, I should instead say that objective reasons are provided by the ultimate facts, not mere “indications” thereof. The more subjective or evidence-based “reasons” might instead be conceptually tied to rationality, as per my “quasi-reasons” below. 26 Indeed, Parfit (1987) takes this as the “central claim” of the self-interest theory. 27 Railton, p.156. 28 Dancy, p.18. 29 Thanks to Jeremy Shearmur for suggesting this example to me. 30 For example, one would plausibly have reason not to entertain the good as a goal. But one could not recognize this reason without thereby violating it, for it would only move an agent who sought the very goal it warns against. 31 Nozick, p.41. 32 Kavka, pp.33-36. 33 Of course, the atomist will allow that facts about other times can provide reasons in the present. But in the example discussed, there seems an important sense in which the reason itself is not present – except, perhaps, through a kind of imaginative projection on the part of the globally rational agent. 34 From a local perspective, the state of intending is worth having, even though the object (e.g. the act of drinking Kavka’s toxin) does not in itself merit intending. The problem arises because we regulate our mental states on the basis of object-based reasons alone (as seen by the impossibility of inducing belief at will). The global perspective enables us to overcome this by treating past reasons for intending as present reasons for acting, and hence transforming state-based reasons into object-based ones. 35 For more on the significance of rational resolutions, see McClennen, pp.24-25. 36 Sorensen, p.261. 37 Quinn, pp.79-90. 38 Sorensen, p.270. 39 Weirich, p.391. References Dancy, J. (1997) ‘Parfit and Indirectly Self-defeating Theories’ in J. Dancy (ed.) Reading Parfit. Oxford : Blackwell. Elster, J. (1983) Sour Grapes. Cambridge : Cambridge University Press. Hare, R.M. (1981) Moral Thinking. Oxford : Clarendon Press. Harsanyi, J. (1980) ‘Rule Utilitarianism, Rights, Obligations and the Theory of Rational Behavior’ Theory and Decision 12. Kavka, G. (1983) ‘The toxin puzzle’ Analysis, 43:1. Kolodny, N. (2005) ‘Why Be Rational?’ Mind, 114:455. McClennen, E. (2000) ‘The Rationality of Rules’ in J. Nida-Rumelin and W. Spohn (eds.) Rationality, Rules, and Structure. Boston : Kluwer. Musgrave, A. (2004) ‘How Popper [Might Have] Solved the Problem of Induction’ Philosophy, 79. Nida-Rumelin, J. (2000) ‘Rationality: Coherence and Structure’ in J. Nida-Rumelin and W. Spohn (eds.) Rationality, Rules, and Structure. Boston : Kluwer. Nozick, R. (1993) The Nature of Rationality. Princeton, N.J. : Princeton University Press. Parfit, D. (ms.) Climbing the Mountain [Version 7 June 06]. Parfit, D. (1987) Reasons and Persons (2nd ed.). Oxford : Clarendon Press. Quinn, W. (1990) ‘The puzzle of the self-torturer’ Philosophical Studies, 59:1. Railton, P. (2003) ‘Alienation, Consequentialism, and the Demands of Morality’ Facts, Values and Norms. New York : Cambridge University Press. Sorensen, R. (2004) ‘Paradoxes of Rationality’ in Mele, A. and Rawling, P. (eds.) The Oxford Handbook of Rationality. New York : Oxford University Press. Weirich, P. (2004) ‘Economic Rationality’ in Mele, A. and Rawling, P. (eds.) The Oxford Handbook of Rationality. New York : Oxford University Press.Reasons and Rationality
Friday, October 13, 2006
Thesis Conclusion [draft]
[The concluding summary of my honours thesis. Links to the earlier chapters are interspersed with the text...]
It’s natural to expect that what can be known without needing to look at the world is closely tied to how the world metaphysically could or must have been. If we can only learn a fact a posteriori, through empirical investigation, we may expect that this is because there are other possible worlds in which the fact in question fails to hold. Assuming that possible worlds are wholly self-contained, we would not expect that examining the actual world could tell us anything informative about other, non-actual possibilities. Modal rationalism draws on these intuitive ideas by positing an intimate link between apriority and necessity, according to which an ideally rational agent could in principle grasp modal space – or apprehend what is possible and what is not – through the exercise of reason alone.
Kripke’s discovery of the necessary a posteriori casts doubt on this picture. There are some necessary truths – e.g. ‘water is H2O’ – which can only be known after empirical investigation. But the modal rationalist suggests that the problem here is merely semantic. We can know a priori how all the various possible worlds are in themselves; what we don’t always know is how to apply our words to them. Some terms, like ‘water’, are not semantically neutral – their application to counterfactual worlds is contingent on how the actual world turns out. That’s why empirical inquiry may be required before we can accurately assess various modal claims. The extra work is required to grant us semantic, not metaphysical, knowledge. We may avoid this need by restating a claim in neutral terms, for which the semantic values are unaffected by whether we consider a world “as actual” or “as counterfactual”. Chapter One thus established that the Kripkean challenge to modal rationalism is toothless after all; the link between apriority and necessity may be restored by restriction to semantically neutral vocabulary.
What’s needed to refute modal rationalism are “strong necessities”, i.e. claims that are true in all worlds considered as actual, despite being conceivably false. This requires that there be coherent scenarios that would not be verified by any possible world. Chapter Two explored this idea further, and assessed Yablo’s arguments for the claim that modal rationalists must recognize such strong necessities. Arguments from meta-modal conceivability provide the greatest challenge here, but I proposed that modal rationalists should respond by treating scenarios as epistemically fundamental, so that meta-modal conceivability is then uniquely determined by the sum of individually conceivable scenarios. Other arguments assume that there are unknowable necessities – an assumption we have no reason to grant, but that at least suggests the intuitive need for a non-epistemic foundation to modality.
Chapter Three set about exploring this idea further. I presented a metaphysically ‘realist’ understanding of metaphysical modality, and defended it against the conceptualist’s skepticism by highlighting its connection to our intuitive ideas about physical indeterminism, objective chance, and the open future. The realist’s primitive conception of modality forces us to take seriously the idea of strong necessities, but they need not give up on modal rationalism altogether. I suggest two principles of modal expansion – the presumption of possibility, and the consistency principle – which together serve to ground modal rationalism on a realist foundation. The end result is, I think, an attractive and defensible view, which preserves many of the intuitive claims we would wish to make about modality. And although it is arguably the conceptualist’s epistemic space that matters for key theoretical purposes, many would dispute this claim – which cannot be fully defended here – so it is worth establishing the viability of realist modal rationalism for those who would place greater weight on this metaphysical modal space.
Chapter Three [draft]
[The third chapter of my thesis, modulo footnotes. See also intro, chapter one, chapter two, and the conclusion. Comments welcome... Post updated 17/10/06]
§3.1 Metaphysical Realism and Conceptualism
Modal rationalism links metaphysical necessity to a priori knowability. We may wonder what this implies about the metaphysical status of modal discourse: can it still be fully mind-independent? The modal rationalist grants that many modal facts will never be actually known – and perhaps even cannot be known by creatures with our cognitive limitations. So the modal facts are genuinely objective, in that they are completely independent of our minds, and may transcend at least the evidence that is practically available to us. Nevertheless, modal rationalists hold that the sum of all possible rational evidence, including that which is accessible only to more cognitively advanced agents, suffices to settle the modal facts. At the end of the day, all (semantically neutral) necessary truths must be knowable on ideal rational reflection. There are no such necessary truths besides those that are so knowable. Modal reality cannot transcend all possible rational evidence.
Why not? Here modal rationalists may split into two camps. Conceptual modal rationalists, e.g. Chalmers, seek to epistemicize modality by claiming that so-called “metaphysical necessity” is really nothing over and above a priori knowability (subject to the 2-D semantical complications discussed in Chapter One). On this view, there is an analytic link – perhaps identity – between the concepts of possibility and ideal conceivability that precludes any gap between the two. That way, modal truth just is the ideal limit of a priori inquiry; it does not answer to the sort of independent reality that might sensibly be considered beyond all epistemic reach. Modal reality is thus a kind of (non-contingent) rational construction. Rather than addressing the metaphysical question of how reality is in itself, modal facts may be considered more fundamentally normative in nature: they tell us what should be concluded at the ideal limit of a priori rational reflection.
Metaphysical Realists about modality, in contrast, wish to uphold the conceptual distinction between necessity and apriority, whereby the former is taken to be a genuinely metaphysical notion – about the world as it is in itself, rather than our (even idealized) beliefs about it. Realists will be more sympathetic to the previous chapter’s conclusion (§2.3) that we can make sense of a ‘gap’ between the two concepts, according to which even ideally rational agents might be inescapably mistaken about the breadth of modal space. Realist modal rationalists must simply insist that there is no such gap as a matter of fact. Further, this fact about modal space will be necessary if true at all (cf. §2.2), so the modal rationalist is also committed to its apriority. But whereas the conceptualist takes the connection to be analytic, realists will instead propose that it is a substantive, synthetic claim about the metaphysical nature of reality. It is this ‘realistic’ version of modal rationalism that I will seek to elucidate and defend later in this chapter. First, we must depart from the conceptualists by taking seriously the idea of primitive metaphysical modality that underlies the radical challenge from strong necessities.
Note that metaphysical realism puts modal rationalism at risk by opening the door to strong necessities. If – contrary to my arguments – there are indeed some strong necessities, then the inference from ideal conceivability to metaphysical possibility is jeopardized. Even so, this might not leave philosophers quite as hamstrung as typically supposed. It is arguably the fundamentally rational notion, rather than the metaphysical one, that we employ in our philosophical theorizing. That is, for the standard theoretical uses of modality, it may be the conceptualist’s space of coherent scenarios that we really need. But I think we have a grip on an independent metaphysical notion in any case, so I will try to bring this out in the sections that follow. My subsequent defense of realist modal rationalism will be of greater significance to those who dispute the theoretical primacy of epistemic space proposed above.
§3.2 Content-Based Modalities vs. Metaphysical Modality
I wish to distinguish two very different ways of specifying a modal space. In the first case, philosophers may isolate and identify the particular modal space they wish to work with by offering a (more or less) formal specification of the contents they wish to include or exclude. That is, they begin with some framework F of rules or limitations, and then define the space of F-possibilities as simply a matter of what is not ruled out by F. [Cf. Van Inwagen: “It hardly follows that, because a certain thing cannot be proved to be impossible by a certain method, it is therefore possible in any sense of ‘possible’ whatever.” What I here call “content-based” kinds of possibility are, for Van Inwagen, mere pseudo-possibilities.] I will say that a specification is “content-based” if its delimiting rules are directly and exclusively concerned with the internal contents of possible worlds, so that one may determine whether or not to allow a world-candidate solely on the basis of descriptions of what that world contains.
For example, nomological possibility is sometimes understood as simply consisting in the non-violation of the actual laws of nature. [Other times it may be understood as ‘compossibility’ with the laws of nature, in which case something that is metaphysically impossible would be considered “nomologically impossible” even if the laws of nature alone provide no grounds for ruling it out.] This specification is content-based insofar as it can be applied simply by examining a complete description of the internal workings of a candidate world, and determining whether any of the described events contravene our laws of nature. Conceptual possibility can similarly be settled simply by determining whether a candidate world-description contains any overt or implicit self-contradictions. This might not be purely formal: if rational insight cannot be captured algorithmically, there will be no finite set of rules that can determine a priori coherence. So the latter may need to be taken as a primitive in its own right. Nevertheless, this modality is “content-based” as I use the term, for it serves to directly fix the breadth of the modal space.
In this chapter, I wish to explore the proposal that metaphysical possibility is not to be understood in such content-based terms. Instead, this modal space is, in a sense, "world-oriented". It is to be characterized first and foremost in terms of its metaphysical nature, thus leaving its breadth of content to be fixed by reality rather than building it explicitly into the concept. This aims to connect with our intuitive notion of ‘metaphysical possibility’ as reflecting ways the world really could have been – a concept whereof our primitive grasp leaves open, at least initially, what breadth of content this modal space contains. The answer is fixed by reality, not our concepts alone. The question of what really could have been is here assumed to be a question fundamentally about the world – or reality in itself – that admits of an objective and exclusive answer. Though philosophers might propose whatever content-based restrictions suit their purposes, the world itself provides just one space of real possibilities.
Of course, this space of metaphysically possible worlds must have some or other breadth, and so be specifiable in terms of restrictions on content. Perhaps it includes all the conceptually possible worlds. Or perhaps it includes only the actual world, as would be the case if things never really had any genuine opportunity to be different. If all else fails, one could simply give an exhaustive specification of each and every world that it includes, and construct their disjunction as the content restriction. Any of these “spatial breadth” properties are prima facie consistent with the concept I’m trying to point to, because its fundamental character lies in a different dimension. Unlike the other modal concepts, we don’t immediately characterize it in terms of breadth or restrictions on content. The criterion for a world’s inclusion in this space is instead its brute modal nature. We don’t ask: “Does this world contain anything which violates such-and-such content restrictions?” Instead we ask the irreducibly modal question: “Is this a world that had the opportunity to be actualized?” Or, equivalently: “could it really have come about?”
Once we have a grasped metaphysical modal space by way of the above questions, we can go on to inquire into the space’s breadth of content – as below. But for now I emphasize that the concept must be initially grasped in these primitive modal terms. You cannot begin by characterizing metaphysical modal space in terms of its contents, because those are not included in the concept as it initially presents itself to us. If you begin with them, you are really grasping a different concept altogether. After all, for any space of worlds characterized in terms of their content, one can still coherently ask: “but might they really have been actualized?” It wrongly remains an open question, unless one builds this modal requirement right into the fundamental conceptual character of metaphysical modality.
Note that this conception makes no explicit demands on what content must be found within candidate worlds. Metaphysical modality, thus understood, is not to be analyzed in terms of any collection of formal rules or laws that must be satisfied, nor even a primitive content restriction such as “rational coherence”. Rather, what matters is simply whether the candidate world is one that really could have been actualized. So long as this external modal property is satisfied, we need not worry about what is in the candidate world. This makes the specification of metaphysical modal space significantly different in kind from the content-based spaces mentioned earlier.
§3.3 Identifying Metaphysical Modality
It might be wondered what, exactly, this notion of “really could have been actualized” involves. (Merely emphasizing the “really” will do little to help one who lacks an antecedent grasp of the concept.) Since it is presented as a primitive or bedrock concept, no reductive analysis can be offered to explicate it. But some general remarks may help bring the intuitive notion to light.
Chalmers expresses his skepticism as follows:It seems to me that we do not even have a distinct concept of metaphysical necessity to which the second primitive [besides rational coherence] can answer. The momentary impression of such a concept may be a residue from initial impressions of the Kripkean distinction between epistemic and metaphysical modality. But once we recognize that this distinction can be explained with one modal primitive, and that there are constitutive ties between the Kripkean modalities, the grounds for this impression disappears. The only concept of a "metaphysical possible world" that we have is that of a logically possible world. If someone thinks they have a distinct concept here, there is no reason to believe that anything answers to it.
I think both challenges may be answered by pointing to a familiar – and metaphysically ‘realist’ – concept of possibility that is sometimes relegated to the merely “nomological”. The concept I have in mind naturally relates to commonplace ideas about objective chance, indeterminism, and the open future. Many people think that the future is metaphysically open, in that it really could turn out in any one of a number of different ways – the truth of the matter hasn’t been decided yet. Each open possibility has some non-zero objective chance of eventuating. Note that this isn’t just a claim about our epistemic situation, or even the rational ideal: it’s about how reality is in itself. This has nothing to do with any actual or possible minds. As a rough heuristic: if God were to rewind time and play it back again, things would unfold differently. Admittedly, this commonsense belief assumes indeterminism. If, instead, the future is already determined, then – given the present state of affairs – there is only one way that things can really turn out. No matter how many times God “replays” history from this point, he’ll never get a different result.
Of course, metaphysical possibility cannot simply be identified with non-zero objective chance. The past is presumably now fixed, so there’s no chance it will suddenly change on us. But even though the past certainly won’t be different, nevertheless we might still think that it could have differed. Perhaps there were open alternatives at a time in the even more distant past. In extending our intuitive notion of the open future back into the past, we will find various (now closed) branches that really were, at one point, dynamically open possibilities. Our concept of metaphysical possibility should at least include the entire history of such dynamic possibilities. They are all ways that the world really could have turned out. Hopefully it is now intuitively clear what I mean by this.
It’s worth pausing here for a moment to clarify what we have established. In exploring the metaphysical specification of modality, we have thus far reached a space of worlds that could be given the content-based specification of “nomological possibilities given the initial starting conditions of the universe”. But such content-based descriptions fail to capture the metaphysical significance – the idea that the world really could have turned out in any of those ways. (Though readers might implicitly project significance on to it, in light of their background knowledge that anything satisfying this content restriction would in fact have had an objective chance of eventuating.) I wish to draw attention to this modal primitive – the one we invoke when thinking about objective chances, physical indeterminism, and open futures – and how natural it is for us to be Metaphysical Realists about it. This seems to be a species of modality that is no mere rational idealization, but rather is truly in the world, as a basic component of reality.
It might be objected that what I’ve pointed to here just is “nomological modality” in some sense. Non-Humeans, at least, could be expected to imbue some form of natural necessity with the primitive metaphysical significance proposed above – in which case the end result will be much the same. Whatever you want to call it, once we have a grip on this ‘realist’ modal primitive, we may ask: could the laws of nature themselves have been different, in this primitive sense? It seems a reasonable question, though of course the nomological impossibility of it is trivial. This suggests that the primitive notion in this vicinity is not, strictly speaking, nomological possibility after all – at least, it doesn’t seem built into the very concept that the laws of nature must be necessary in this primitive sense. We can always stipulate such a content-based restriction later, if we need it for other purposes. But the core concept here is – prima facie – potentially broader than that. So I think ‘metaphysical possibility’ is the more fitting term.
We have here a metaphysically ‘realist’ modal concept that has worldly application: at the very least, it spans the entire history of dynamic possibilities or “open futures”. This undermines the skeptical basis for conceptualism – we should be realists about metaphysical possibility instead. But how far does it extend? We are now faced with the awesome questions of why our universe exists at all, and whether a wholly different universe – say with alternative laws of nature or initial conditions – could have existed in its place. This provides the focus for the next section. Could absolutely any coherent scenario really have been actualized, as the modal rationalist proposes? Or are some rationally apparent possibilities necessarily excluded by the nature of reality, creating “strong necessities” that fall outside the 2-D framework and falsify modal rationalism?
§3.4 Two Principles of Modal Expansion
To recap: we have a space of scenarios, each of which represents a way for the world to be. We might think of each of those “ways” as being a maximal property, just one of which is instantiated by the actual world, and hence is “the way the world is”. That these various properties exist is, it seems, a merely ontological fact. What we’re interested in is the modal fact concerning which of these rival properties (scenarios) had a real chance to be instantiated (actualized). The answer will yield our space of metaphysically possible worlds. Any leftover scenarios will be coherent ways for a world to be, but nevertheless the world could not really have been such a way. They are the ways that “never stood a chance”, so to speak. It might already be thought that there’s something very strange about the idea of such leftovers. Let me offer further grounds for such skepticism.
The above discussion frames the modal question in terms of a positive demand for some reason to think that a scenario had the opportunity to be actualized. This presupposes that scenarios are “modally inert” by default. Their being is merely ontological, and some further modal property or relation needs to be added to them in order to make them “really possible”. They must be targeted by some potentially world-actualizing mechanism – perhaps a Leibnizian God who surveys the space of possible worlds before deciding which to bring into actual existence. But this notion of an atemporal process of worldly “becoming” is of dubious coherence. There is no time before time began, during which such a process of selection could take place. We might take this to indicate the metaphysical necessity of our actual laws and initial conditions – thus contradicting modal rationalism. Or we might reframe the question in a way that escapes these problems. Here I seek to explore the latter option.
We might achieve this by framing the question in negative terms, or asking whether there is any reason why a described world-candidate could not have been actualized. Here we treat possibility as the default assumption: absent any reasons to the contrary, we assume that each way for a world to be is indeed a way that the world really could have been. So long as there is nothing necessarily preventing a candidate from being actualized, it should thereby be considered possible. It does not require any positive mechanism that could have brought it about, or “given it a chance”. No such chance need be given; rather, it comes for free. We might say that a candidate’s natural state is possibility – additional reasons are required to preclude its possibility, not to grant it. Let us call this principle the presumption of possibility. It may allow us to pursue modal inquiry whilst avoiding the confusion inherent in positive demands for a world-creating mechanism.
The negatively framed question also seems more susceptible to being answered. The question of what might bestow metaphysical possibility on a world-candidate seems hopelessly mysterious. But if we ask what kind of thing could preclude a claim from being possible, we find an obvious answer, namely, inconsistency (or a priori incoherence). The consistency principle claims that this is the only answer available, i.e. that a priori incoherence is the only barrier to possibility. After all, we have no trouble granting that an inconsistent state of affairs could not have obtained. But why think that a coherent scenario could not really have been actualized? Such a proposal would seem entirely unmotivated – there is nothing intrinsically disqualifying about the scenario, and there doesn’t appear to be anything external necessarily preventing it from being actualized either. So it seems most reasonable to conclude that any coherent scenario really could have been actualized after all. The combined effect of my two “expansionist” principles – the presumption of possibility, and the consistency principle – is to lead us back to modal rationalism, only this time with a realist metaphysical foundation.
Although the proposed principles seem quite plausible to me, they could reasonably be denied. Of particular concern is the idea that nothing is “necessarily preventing” coherent scenarios from being actualized. Given that a scenario is in fact not actualized, we might wonder why that is. Whatever the actual reason why some other conceptually possible universe does not exist in place of ours, perhaps this very same reason holds of necessity, so that the other universe could not really exist in place of ours. If we take actual existence to be a matter of brute fact, why not metaphysically possible existence likewise? (Perhaps they come down to one and the same fact, viz. our universe’s origin.) Whereas I formulated the above principles in order to sidestep unanswerable questions about ultimate origins, critics might consider stopping right there to be the more appropriate response. As indicated earlier, the metaphysical realist might conclude that the origin of our universe could not really have been any different. I have shown how modal rationalists might hope to avoid this result, by formulating plausible principles of modal expansion. But a more thorough defense of these principles awaits further work.
Monday, October 09, 2006
Chapter Two [draft]
[Here's the current incarnation of Chapter Two of my thesis. See also the intro, and chapter one. I manually added a couple of substantive footnotes below (see asterisks), but the rest are still missing. Hopefully the logical symbols will display properly in most browsers!]
§2.1 The Idea of “Strong Necessities”
We have seen that standard examples of the necessary a posteriori pose no threat to modal rationalism. They don’t involve any shrinking of modal space, and can be explained away as involving semantic rather than metaphysical ignorance. For all that has been said so far, it remains plausible that each coherent claim (i.e. that cannot be ruled out a priori) has a non-empty primary intension, or is verified by some possible world, in the sense that the claim is true of that world considered as actual. This may be understood as the central claim of modal rationalism: for every conceptually coherent scenario, there is a possible world to match.
This is the claim that must be denied by the opponent of modal rationalism. They must hold that there are not enough possible worlds to go around. This is what’s needed to break the link between apriority and indicative necessity. A claim could then be true of all possible worlds – whether considered as actual or counterfactual – without being a priori, because there is a coherent yet strictly impossible scenario that purports to falsify the claim. We may call a claim with these modal properties a strong necessity. These amount to a posteriori necessities with a necessary primary intension: not only are they true in all worlds considered counterfactually, but also in all worlds considered as actual. Despite this, they fail to be a priori because we cannot know a priori that the worlds it is true of (considered as actual) really exhaust the possible worlds. We think that there are others – we can imagine coherent scenarios that falsify the strong necessity – but those scenarios we imagine fail, without our realizing it, to correspond to any genuinely possible world. Not all rationally apparent possibilities are real possibilities.
An example of this position could be found in a theistic view according to which God is a necessary being even though his non-existence is conceptually coherent and so cannot be ruled out a priori. We can imagine all sorts of scenarios that don’t contain any deities, but this theist will deny that they correspond to any genuinely possible worlds. They will insist that God exists in all possible worlds, and our failure to grasp this is due to the rational inaccessibility of modal space. A priori reflection does not suffice to establish what possibilities there are. Hence we might mistakenly conceive of Godless worlds without appreciating the brute fact of their intrinsic impossibility.
This anti-rationalist thesis can be further clarified in terms of Chalmers’ construction of an “epistemic space” of a priori coherent scenarios. Without getting into the details here, we may consider these scenarios to be equivalence classes of maximally consistent sentences in an idealized language, individuated by their a priori implications. We have a priori access to this epistemic space, since it is explicitly defined in terms of rationally coherent possibilities: for every claim that cannot be ruled out a priori, there is a scenario which verifies this claim. Further, the idealized language is – modulo ‘centering’ indexicals – semantically neutral, so that we do not need to know which world is actual in order to fully grasp the meanings of the terms or know how to apply them to other situations. This entails that truth is scrutable in epistemic space, in that we have a full a priori grasp of what is true in each scen