deontically perfect worlds andprima facie obligations

Philosophia Vol. 3 No. 4 Pp. 429 -438 October 1973

DEONTICALLY PERFECT WORLDS AND PRIMA FACIE OBLIGATIONS

RICHARD L. PURTILL

In what follows I wish to consider certain objections to some suggestions put forward by Jaako Hintikka as to a semantics for deontic logic. 1 Hintikka suggests, in effect, that we apply to deontic logic the same sort of semantical approach that Hintikka has shown to be so successful in modal and epistemic logic, an approach based on the notion o f "pos s ib l e " or "'alternative" worlds. The idea of an "epistemically possible world" or "epistemic alternative" rela- tive to the knowledge possessed by some person, proved fruit- ful in epistemic logic: Hintikka now suggests that we consider "deontically possible worlds" or "deontic alternatives" as a basis for the semantics of deontic logic. But the idea of a deontic alternative is far more full of pitfalls than that of an epistemic alternative.

An epistemic alternative is a possible world consistent with all that is known by a certain person. Thus epistemically possible worlds are a subclass of logically possible worlds. (Incidentally, the real world might rather neatly be defined as the unique possible world consistent with all that is known by an omniscent being.) But a deonticaUy possible world cannot be defined so easily. Hintikka suggests that i f / a is a description of a possible world then:

A deontic alternative to a given world, say the one described by #, is intended to be a kind of deontically perfect world, when viewed upon f rom the point of view of

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the norms specified by #. This requirement of deontic perfection means that all of the relevant duties are fulfilled in the alternative world. They naturally include all duties obtaining (in virtue of the normative system specified by #), in the alternative itself, no matter whether they obtain in the world described by # or not. These duties are, of course, based on the normative principles in ~, but they need not themselves be duties obtaining in the world described by #. A case in point might be a duty incurred by making use of a permission that obtains in #, a permission not itself utilized in the world/~ speaks of.(op, cit. p.71).

A number of problems arise about this account. First, what is it for "all of the relevant duties" to be "fulfilled in the alternate world"? Suppose (as seems probable) that in a world which contains no persons there are no obligations. In such a world are "all of the relevant duties" fulfilled or not? One account of what it is for "all relevant duties" to be fulfilled in a world is just that in such a world "Op D p" is logically true. But of course in a personless world "Op D p" is trivially true, for "Op" is always false. But if we are to say that in a personless world there are no obligations, then we must, to be consistent, say that in a personless world every- thing is permitted (since "Op" and "O'x,p" are always false '"X, Op" and '"x,O'x,p" and therefore "p,x,p" and "Pp" are always true.) Of course we might specify that in a deontically perfect world there must be obligations (and therefore persons). But if we do, how many obligations (and therefore persons). But if we do, how many obligations must there be? One? As many as in the actual world? Not fewer than in the actual world? Thus my first questions to Hintikka would be: "Must there be obligations (and persons) in a deontic alternative? If so, how many obligations (and persons)? And how do we identify the same obligations (and persons) in different possible worlds?"

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Our next problem is even more serious. How long must "all the relevant duties" have been fulfilled in a deontic alternative? As long as there have been persons? But this will not work, for in a world in which persons had always behaved as they ought, there would never have been wars or crimes, and thus there would never have been duties to make reparation to the victims of wars and crimes. But in the real world there are definitely such duties. Thus it could not be the case that all the duties which we have in the real world we would have in a deontically perfect world. But if this is so, we cannot answer our previous questions by saying that at least as many obligations exist in deontic alternatives as in the real world (or at least we cannot say that the same duties exist in the alternatives).

Yet further problems arise if we ask what persons exist in deontic alternatives to the real world. Do I exist, for instance? But perhaps one of my male ancestors raped one of my female ancestors and I would not exist except for this rape. But in a deontically perfect world surely there are no rapes. Thus how could I exist in such a world on that supposition? We could, o f course, begin tinkering with history, marry off the rapist and his victim in our deontic alternative, for instance. But perhaps the victim has married and had other children by her husband before and after the rape, children who have descend- ants living now. And making all the necessary readjustments would make the history of the deontic alternative more and more unlike the history of our world.

I see only one solution to these problems, which is to say that a deontically perfect world must be a possible world which has had a history just like that of our world up to a given instant, but after that instant has the characteristic that f rom then on "all relevant duties" are fulfilled. To suppose a deontie alternative, then, is just to "Suppose that from this instant on, everyone does their du ty ."

But this will not work for two reasons. First, it is incon- sistent with what Hintikka says, for he supposes that there

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can be, e.g., permissions not utilized in ta but which are utilized in some alternative to /a. Second, many obligations arise from an expectation that others will fail in their duties. Sam must provide for his sister Sally's children, since he knows his worthless brother-in-law will not. Indian troops must guard the surrendered Pakistani soldiers, since the Bengalis will not respect their surrender. In a. deontically perfect world such obligations could not arise.

A further problem arises from Hintikka's talk of normative principles as being included in the description of a possible world. Many ethical objectivists would want to say that the same set of ethical principles would apply to any possible world, just as logical principles apply to any possible world. Does Hintikka want to deny this? (As he seems to when he talks of the norms specified by #). If he does, what view does he wish to substitute? Thus it is very difficult to say whether Hintikka's machinery of "deontic alternatives" is viable, for too many unanswered questions arise with regard to that machinery.

I now wish to alter my focus and consider a collateral problem, the problem of how prima faeie duties are to be distinguished from "absolute" duties in terms of the machinery of Hintikka's system. This will cast an indirect light on certain further problems connected with Hintikka's semantics for deontic logic.

Hintikka suggests that the general form (but see below) of a statement of prima facie obligation is "O(p D q)," while the general form of a statement of "absolute" obligation is "p D Oq." In terms of the "deontic alternatives" interpreta- tion this means that a statement of prima facie obligations says "In a deontically perfect world, if you brought about A, you would bring about B," while a statement of "absolute" obligation says, "If you bring about A, then in a deontically perfect world you would bring about B." But this has very odd consequences.

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Let us first consider the case where the act described by "p" in an expression of the form "O(p D q)" is a forbidden act, contrary to duty. Such an act can, of co.urse, never occur in a deontically perfect world. Thus "p" will be false in any deontic alternative, so of course "q" may be anything you like. Thus Hintikka's system will unavoidably contain the "paradox of derived obligation." For example, there will be a prima facie obligation to murder ten thousand men if I tell one lie. Some writers have found some oddities acceptable, but they seem to me to play havoc with any coherent idea of a prima facie obligation.

But now consider expressions of the form "p ~ Oq." Provided that "Oq" is true, that is to say, provided that "q" is true in any deontically perfect world, then "p" may be any statement you like. Thus, if loving my neighbor is an obligation, then if I scratch my head I am absolutely obliged to love my neighbor. Odd but harmless, you may say. But now consider how, if at all, we can make intelligible statements about the way in which a promise can oblige you to perform a certain action or an injury to someone can oblige you to make reparation. Suppose you regard these as prima facie obligations and formalize them on the model of "O(p ~ q) ." Then the promise will oblige you to its performance no more and no less than any forbidden act "obliges" you to perform that act. Any crime against anyone "'obliges" you to the act of reparation we are considering no less than an injury speci- fically relevant to that particular reparation. How, in other words, are we to distinguish trivially true statements of prima facie obligation from important ones? Not by requiring "p" in "O(p D q)" to describe a permissible act, for some forbidden injuries create obligations to make reparation, and some forbidden promises create at least prima facie obligations to carry out the action promised.

On the other hand, the form "p D Oq" will not do for obligations derived from promises, injuries, etc., for if "Oq" is true it will be trivially implied by any statement. Hintikka

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may, of course, turn to stronger connectives, but consider the complexities of interpreting, e.g., "O(p---~ q)" or "p ---~Oq." The first must be read, "In all deontically perfect worlds it is true that in all possible worlds that if p then q," and the second will read, "In all possible worlds it is true that if p then in all deontically perfect worlds q is true. Such statements may make some sort of sense, but it is difficult to see what kind.

In addition, I am not sure that Hintikka's machinery will enable us to do justice to many interesting statements about prima facie obligations. Thus in a given set of circumstances I may have prima facie obligations to rush my wife to the hospital, give my name and insurance company to a driver I have injured slightly, and get to a promised appointment. The first prima facie obligation outweighs the second, which outweighs the third. Thus my "absolute" (or as I prefer to say) "str ict" obligation is to rush my wife to the hospital. Now this situation might be describable in terms of Hintikka's system, but I do not see how. If "p " represents "I sideswipe a car on the way to an appointment, injuring my wife seriously and the other driver slightly," "q" represents "I rush my wife to the hospital," " r " represents "I give my name and insurance company to the other driver," and "s" represents "I keep my appointment ," where "q" , " r " and "s" are in- compatible, then surely we cannot symbolize my obligations by any of the following:

O(p D (q. r- s)) p D O(q. r- s)

O ( p D q ) . O ( p D r ) - O ( p D s ) (p D Oq) �9 (p D Or) �9 (p DOs), etc.

In fact, no machinery which does not enable us to compare obligations with regard to strength is at all adequate to deal with prima facie obligations.

Furthermore, we need such rules as " I f doing A obliges you to do B, and you are obliged to do A, then you are

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obliged to do B" for both prima facie and "absolute" or strict, obligations. In fact I suspect that any adequate system of deontic logic will need separate operators for strict and prima facie obligation, and rules connecting the two, just as any adequate modal logic needs separate connectives for strict and materials implication and rules connecting the two. No mere difference in the order of "O" and "D" will capture the difference between strict and prima facie obligation, pace Hintikka's suggestion.

Furthermore, expressions of the form "p D Oq" have peculiar drawbacks. Such expressions will of course transpose to expressions of the form "•Oq D •p" which is equivalent to "p,x,q D ,X,p." Thus from a statement about is permissible we could infer a statement about a matter of fact.

How odd is this? Not odd at all if "p" is a logically sufficient condition of "Oq" for then ' ' , ,Oq D ,x,p" will mere- ly say that if we do not have an obligation then it cannot be true that a sufficient condition for having an obligation obtains. But as James and Judith Thompson have pointed out, 2 no mere statement of fact can do the job of being a logically sufficient condition for an obligation.

However, Hintikka can quite correctly reply that it was not statements of the form "O(p D q)" and "p D Oq" that he proposed as the proper forms for prima facie and "absolute" obligations, but rather statements of the form "O((n-p)D q)" and "(n 'p)D Oq," where "n" represents some set of norms (op. cit. p. 91). This avoids the Thompsons" objection, but at the cost of greater complication. By transposition and De Morgan's rules these forms lead to "O('x, qD (,x,n v ,X,p))" and '"X,Oq D (*n v ,x,p)," then by Definition of Material - Implica- tion and Exportation to "O(('X, qm)D u p ) " and "('x,Oq. n)

,X,p." But the set of norms represented by "n" are part of the description of /z, so one would think that there is no question of them being false in /~. Thus from a statement of " a b s o l u t e " ob l iga t ion " ( p ' n ) D Oq" we could derive "n D ('x, Oq D ,x,p)" and then, since "n" will always be true in

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#, find ourselves again with the puzzling '"X, Oq D ,X,p." This

will have to be read as something like "Given certain norms, n, if it is not obligatory to bring about q then it is not true that p ." But now we see that " p " cannot be anything as simple as "I promised to bring about q," for it can easily be true that I promised but was released from my promise, or that I promised but a more serious obligation outweighed my p r o m i s e . Thus in any case where we can truly write

"(n-p) D Oq," " p " must contain a statement of ceteris paribus conditions, and these must be of two kinds. First, the ceteris paribus conditions must include matters of fact which bear on

the obligation, e.g., "I promised and I have not been released from my promise and the promisee has not died and the situation has not changed in such a way. as to make my promise otiose . . . . " Second, the ceteris paribus conditions must include a denial that any overriding obligations exist.

In the case o f prima facie obligations, of the form "O((n.p) D q)," it might seem that " p " could be much simpler, for Hintikka seems to assume that in a deontically perfect world there would be no conflicts o f obligations. (It is not clear whether he assumes also that there would be no need for ceteris paribus conditions of the first kind, e.g., re- lease from promises, changes in situation, etc.). But I aria not at all sure that this makes sense: how could there be a w o r d having any recognizable relation to our world in which there were no conflicts o f obligation? What would such a world be like? I suspect that Hintikka 's position here is tied up with a position he takes elsewhere, 3 that there is something wrong in e.g., breaking a promise "because a more important duty comes into being." He agrees that we have a valid inference

O(p ~ q) (Giving a promise commits one to keeping it) O • q (One ought not to keep the promise because of

the other duty)

O ,x, p (One ought not to have given the promise)

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and that the first premise is a statement of prima facie obligation. Here "p" seems to be taken as simply "a promise was given," with no ceteris paribus conditions. But if it is as simple as that, some other circumstance may make it true that "Op," giving us "Op �9 O ,x, p" as well as "Oq �9 O ,x, q." This is intolerable for strict obligations, but quite in order for prima facie obligations, which are by nature obligations which can (and sometimes do) conflict. Any sound deontic logic must take account of this fact, and must recognize first the prima facie obligations can conflict and second, that when they do there is nothing morally objectionable about not carrying out some of them. It is always wrong not to obey a strict obligation, but often right not to obey a prima facie obligation.

There are, of course, other tactics that might be tried to save Hintikka's approach to deontic logic. But it is very much easier to take a fresh start and recognize that we need a new approach to deontic logic, one which recognizes the difference in kind between prima facie and "absolute" or "str ict" obligations. If we symbolize strict obligation by "O ~" we will find some parallel rules:

Op =- %P*p (Op "Oq) D O(p q)

O(p D q) D (Op D Oq)

O~3= ~ P %,p (0 io - 0 ~ ) D O ( p -q)

O ' (p D q) D (O 'p D O'q)

However, we will also find that rules such as

'x,(O'p �9 O ' * p )

P'p v p',x,p

hold only for strict obligation and permissibility and that

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Hintikka's valid argument is ambiguous between

I II III IV

O'(p D q) O'(p D q) O(p Dq) O(p D q)

O' * q O * q O' "~,q O'X,q

O'~x,p __ - - O'x,p

where II and III lead to no valid conclusion, IV is harmless

since prima facie obligations can conflict, and although I is

valid it will not represent the situation Hintikka had in mind.

In fact, we need further complications, for obligations do not float in the air but are attached to persons. Thus "Oap,"

on the model of "Kap," is our proper operator. Furthermore

we can hardly avoid some reference to time: a past promise can oblige me now, etc. But before we begin building on such

new foundations it must be made clear that the foundations proposed by Hintikka will not support an adequate structure.

WESTERN WASHINGTON STATE COLLEGE BELL1NGHAM, WASHINGTON 98225

USA RECEIVED: 19 JUNE 1972

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deontically perfect worlds andprima facie obligations

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