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A Framework for IntentionsIntended States of AffairsBoris Hennig, 10. 10. 1996 Introductory Remarks to Nuel Belnap
(1) You may wonder how a
revised version of my paper (Tracing through
Worlds, Ms. Leipzig 1. 7. 1996) could be titled 'A Framework for
Intentions'. Indeed, as I read my paper once again, I could hardly
find anything substantial in it except for the attempt to
formulate a de dicto / de re
distinction (that Werner Stelzner
gives in De Dicto, De Re und
Quantifikation in der
alethischen Modallogik;
Untersuchungen zur Logik und
Methodolgie 2, p. 54) in terms
of Gupta. In a
recent lecture, however,
Klaus Jakobi convinced me that
there is no use in spelling out
this distinction in technical, that
is, linguistic terms
(Potentialität und
Possibilität, unpublished
lecture held at the 17th german
congress for philosophy,
XVII. Deutscher Kongreß
für Philosophie, Leipzig 23. -
27. September 1996, Leipzig
septembre 25th). (2) Unfinished as the following paper is (for instance, I could not even take into account 'Intention' of G. E. M. Anscombe, Oxford 1959 and 'Intentionality' of J. Searle, Cambridge 1983), rough and fundamental critical remarks will be the most helpful reply to it. Please do not withhold your very own opinioun on the subject; for my 'framework' will previously not be filled within the next 6 months, that will not prevent me from thinking myself. (3) I wrote this text without any tutorial advice. I can only hope that there is no comlete nonsense in it, as regards the English language or formal logics. The Purpose of Modal LogicsI felt that the
first question in a system of modal
logics must be its
application. There is obviously no
use in debating about the status of
possible worlds, unless they can be
hoped to solve a particular
problem. Aldo Bressan has developed
a very complete and multi-purpose
calculus in his book, and as a
nonphysician I have nothing to add
to his book as regards
physics. Since it is highly general
and can be translated into
extensional logics, every calculus
based on his is at least
legitimate, concerning the
technical matter. Besides the
admittedly very important concept
of physical modality, however, I
think there are two generalkinds of
intelligible approaches (Cf. Loux
p. 259): The
notion of 'intending something' is
surely a central and fundamental
one in most kinds of social
science. Theories of communication,
consciousness and agency use it
frequently as a basic concept, so
that a worthwhile purpose for modal
logics might be to provide
technical requisites for
formulating 'intended states'. It
may be helpful to get a certain
distance to the natural language,
for the question whether it is
possible to intend something
without being able to describe it
in a language is not
trivial. Initially, however, it
seems rather clear that only states
of affairs can be the objects of
intentions. Even a description
like 'A wants the thing x' appears to
be better replaced by 'A wants to have
x'. A sentence of the kind 'A intends
the thing x' does not seem
intelligible -at least not in
German. There are several
possibilities to argue that this
kind of intended entity has a
merely 'linguistic' being, for it
is precisely the 'content of some
(uttered or implicitly accepted)
sentence'. A Classification of Modal EntitiesThe traditional distinction between possibilitas and potentialitas can be rendered by two different kinds of sentence schemata. I am indebted to Klaus Jakobi for this view. The distinction that is drawn by this means is independent from two other possible distinctions: the one between using 'can/must' and 'possible/necessary' to articulate modality, and the other one between modalities de dicto and de re. It is illuminating to consider first a latin formulation of the mentioned sentence schemata: (1) Possibile est Socratem currere, Similar sentences can be construed for the case of necessity or contingency, and a distinction according to the one between possibility and potentiality can be used here, too.Sentence (1) ascribes possibility to a state of affairs, the modality in (2) appears to be rather the power or potency of the subject Socrates.Schema (1), in which the modality is attached to the 'oblique' sentence Socratem currere can be rendered by two less elegant formulations: It can be that F(a), versus a can be F, Again, the first two sentences can be said to attribute possibility to states of affairs, the second to state potencies or powers of certain things (that may be denoted extensionally). Although G. H. von Wright takes exactly this to be the distinction between de dicto and de re modalities (Essay on Modal Logic, Studies in Logic and the Foundations of Mathematics, North Holland, Amsterdam 1951, p. 28 and passim) the latter can easily be combined with the two schemata:
In this tabular I have inserted the respective entities of which modality is predicated. By 'individual' I sum up the content or sense of all kinds of linguistic means to refer to (sets of) individual things, that is proper names, rigid designators, definite descriptors, individual variables and constants, common nouns and the like. As I already said, the question whether there are states of affairs different from (or even independent of) propositions will be left open. Therefore, every entity to which possibility is attached can be called 'state of affairs'. The horizontal distinction can be compared with the Fregean difference between sense and reference, but anyway I will be concerned with the vertical one between possible states and possible predications. IntentionsIntentional ActionI have not yet dealt with the full range of requirements that are given with the task of explicating the phrase 'A intends X'. In the context of this paper, I will have to restrict the investigation on the concept of modality to be used. In order to clear the environment in which this is to be done, I will simply quote the explication of 'intentional action' that Tuomela uses in his recent book, and add a few remarks. An agent A intends to perform X only if This quotation is from Tuomela's 1977 book (Human Action and its Explanation, Dordrecht, Reidel 1977, p. 133). In The Importance of Us, he adds the following analysis of intentional action: An action performed by a single agent was intentional (in the core sense) relative to D if and only if, relative to D, the result of that action was something the agent aimed to bring about by his acting (...); and the action was performed approximately as planned (p. 69). Here, D stands for a description of the intended state.Obviously, these analyses still have to be analysed. The Object of IntentionsTuomela's talk about the status of the intended entities is not very careful, especially in his use of 'object'. I have to admit that it is hardly possible to avoid to speak of objects of intentions: I did so myself above. Intentions, as I have said, do not aim at individual things, but rather at states or manners of things, and Tuomela does not seem to claim anything different. Therefore, 'object' must not only be taken in its widest possible sense, it must rather be taken in a sense that ex cludes 'things' from its range. Indeed, in Tuomelas first analysis 'realize an object' and 'perform X' seem to have at least the same syntactic category. In these clauses, 'object' denotes an action. But as regards the meaning of 'object' in phrases like 'A wants the object in question', there seems to be a shift from states to things. Even if this is to be passed over, Tuomela appears to draw a distinction by this difference that I do not want to adopt. He seems to suppose that states of affairs can be wanted, but only the results of actions can be intended. At least, the result of a performance can be 'wanted', and I think it should be possible to 'intend' certain states that are no direct results of one's own actions. Generally, I prefer a threefold distinction between 'wants', 'wishes' and 'intentions'. It may be that an intention involves a commitment to act, and by that way always aim at some result of an action. But that specifies the difference between 'wishes' and 'intentions'. 'Wants', I want to claim, need not even aim at some particular state of affairs, let alone, a resulting state of affairs. Both analyses deal with the notion of 'intending to perform X' or 'performing X intentionally' instead of 'intending Y'. There is a difference between an intentional action and an intended one. An intentional action is an action by wich an agent intends something (possibly different from the action), and this is what Tuomela claims to analyse in the second quotation. So the latter analysis deals with the intended state of affairs rather than with an intended action. As 'in contrast to wants and desires, intentions can be regarded as commitments to action' (The Importance of Us, p. 53), it seems plausible that every kind of intending is covered by this second analysis. One can imagine, however, to intend passive rather than active, as in 'A intends to do nothings against Y'. The more general formulation will be 'A intends the state of affairs X', where it must be added, that one can only intend states of affairs one is (in any kind) involved in. I am not quite sure whether 'A intends the result of performing X' is equivalent to 'A intends the state of affairs X he is (in any kind) involved in' --- maybe the concept of 'performance' can be widened sufficiently. But even the notion of involvement must be modified: A need not be involved in the intended strate itself, but only in making it possible. I summarize these points by making the following claim: A intends X only if A can be involved in making X possible. To give an example concerning the degree of involvement: A borderline case of an intended state could be, that A intends that some other person B suffers from a desease D by withholding the message that an epidemic is spreading. The content of the intention will be: 'B suffers from D'. Hopes vs. BeliefsStekeler-Weithofer remarks that it is not useful to speak of believes in this case, for 'to believe something' is not to be confused with some attitude to a possible state. (Zum Problem gemeinsamen und kommunikativen Handelns bei gemeinsamen Zielen, unpublished lecture on the occasion of Tuomela's participation in workshop 8 of the 17th. german congress for philosophy, XVII. Deutscher Kongreß für Philosophie, 23. - 27. September 1996 in Leipzig. He contributes this point (without explicit reference) to Nuel Belnap, but his according manuscript is 'not to be cited'.) A intends X only if A hopes that X will obtain.
Intentions and Driving ForcesIn the first quotation, Tuomela is careful enough to state merely the 'only if'-side of an according definition. Indeed, I do not believe that the coincidence of a belief and a want is sufficient for an intention. Roughly, Tuomela seems to approach the notion of 'A intends X' by adding (i) a belief and (ii) a consistency clause to the according 'A wants X'. It seems plausible that it is possible to 'want' inconsistent sets of states, but not to 'intend' them. The concept of 'wanting', however, is not a sufficiently clear one. To get things lucid, it is convening to seperate 'wants' as far as possible from 'intentions'. Therefore, a want may be posited on a level together with driving forces, urges, impulses and unconscious desires. So it may be possible to want (a) impossible things, (b) things one believes to be evil and indecent, (c) undescribable things and the like. Intuitively, I think it is further possible to want individual things, as different from wanting states of affairs to obtain. 'To want' can be described as to be driven into some direction. The categorical difference to another form of endeavouring can be seen in a somehow more detailed representation of the wanted item. This could be called 'will' or 'want2 '. The important feature of this higher-level want2 seems to be that it imposes a complete 'virtual' difference between the objects: on one side there are the objects that fulfill the want2, on the other side the ones that do not. It is essential that this difference can be known in advance, that is, independent of the actual circumstances. For instance, one can imagine two kinds of 'wanting something to eat': hunger and appetite. Hunger may be satisfied by taking appetite suppressants, while appetite for something particular cannot be really satisfied this way, but only brought to an end. This is nearly a cognitive or linguistical property, for there remains only a small step to such entities that divide the 'logical space' in verifying and falsifying states of affairs, like a sentence may be claimed to do (Wittgenstein, Tractatus 3.4). Intention seems to be a rather fundamental want2 of the latter sort. I think it is possible to explain 'verifying a sentence' and 'saturating a concept' by regarding sentences as special kinds of intentions. There is a long tradition of using the latin 'intentio' for 'meaning', i.e. the greek kataphasis (Boethius in De Interpretatione) and the arabic ma'na (Michael Scotus in the Avicenna latinus), cf. also Ockham's Summa Logicae I,12. Besides some driving forces into a suitable direction, every intention must at least implicitly contain a description X of a possible state of affairs. It is important, that this description uses intensional concepts: it is possible to intend states of affairs that are merely possible, but will never happen to be actual. Generally, there will be no use in describing aims for already obtaining states of affairs. Modality AppliedWhere to apply ModalityThere are two occasions for applying intensional language. First, the agent must believe that the intended state of affairs can ontain. Such a belief must have the form A believes that XB can obtain, Here, the state of affairs occurs in a belief-context and is therefore marked XB. In order to keep the truth conditions of the whole sentence constant, several things must be considered. For instance: If A has a belief about a certain x, does he know all the relevant properties of x, especially that it is identical to some y? The intention itself must be articulated in an intensional language, too. That does not have to take place in a particular belief-sentence. It must be intelligible to say of someone else 'He intends X', although one does not share the according beliefs. The reference to intentions of other agents is independent from their respective knowledge or linguistic competence. When a state of affairs appears in such an intention-sentence, therefore, it can be dealt with less restriction: A intends the state of affairs XI. It gets obvious, by the way, that no intention is reducible to a driving force and a corresponding belief: Intention can be described without the notion of belief and is still more than a mere driving force. Things and States of AffairsTo decide which kind of modalitiy has to be used is not as easy as it seems. There are two arguments: (a) The object of an intention must be a state of affairs. Therefore the modality must be a possibilitas. The distinction between 'actual possibilities' and 'possible actualities' is taken from Robert Musil (Robert Musil, Der Mann ohne Eigenschaften, Reinbek 1978, Chapter 4: Wenn es Wirklichkeitssinn gibt, muß es auch Möglichkeitssinn geben). An actual possibility can be described as a possible combination of existing entities, whereas a 'possible actuality' can involve nonexisting entities and even disregard some laws of nature. (*) A intends a to be an x such that F(x). But there is a further difficulty: Suppose that an agent A intends to have a white marriage, but does not want to marry a particular person yet. That seems plainly intelligible: A can be supposed to say later to his wife (or husband): 'I always wanted to have a white marriage'. Of course, this is a higher level want2, and adding the plausible belief (that a white marriage is possible), there was indeed an intention without an object. It could be analysed according to (*) in the following way: A intends himself to be an x such that F(x), but the involvement of the agent himself was already obvious (by saying that he intends something). Further, there might be intended states that do not themselves include A (for instance, the help for developing countries). Anyway, in Bressans calculus the far more elegant solution is already provided: both a and F(x) have to be intensional concepts. I. If A wants to have a white marriage, this marriage cannot be described as an actual marriage with other persons involved in. It may be that A sees such an event somewhere and says to himself 'when I grow up, I want to do the same'. But 'the same' cannot be reached by elimininating the concerning individuals and replacing them by A and his wife (her husband). In such a procedure, Peter marries Susan in the particular manner M, therefore the manner M cannot be extensionally the same. It is obviously not the marriage of Peter and Susan in which A and x2 enter instead of Peter and Susan. It is rather some counterpart of this actual marriage. Therefore, a logic of intentions must be able to determine counterparts of events, independent of the concerned individuals. Even the agent himself is not in general to be excepted from this: it is possible to intend states of affairs with out being part these very states of affairs. A father can intend, for instance, that his unborn son visits the highschool. There is a similar example in Davidson, p. 137. Consider also the schema 'A intends X under all circumstances'. II. There is another, more farfetched, argument for event-counterparts. Anil Gupta (p. 11) construes common nouns by a very special kind of predication. He analyses a sentence like Any man who owns a donkey beats it by seperating the attribution of a certain kind from that of a predicate: (for all D, x) (for all (M, y) Oyx, z) Bzx. The only ordinary predication takes place in the phrase Bzx, that is, 'z beats x'. The other predications, D 'to be a donkey', M 'to be a man' and Oyx 'y owns x' are done by common noun-clauses (According to Definition 1 (vii), p. 7, '(M, y) Oyx, z' is a single common noun). By such a clause, it can be said, a 'this' (x) is transformed into a 'this something (Loux, p. 134), that is, into an x of a particular kind. This can be called 'species-predication' in contrast to 'form-predication' (which transforms a 'this' into a 'this such'). Cf. Loux p. 120 and 137: 'forms lack their own built-in principle of individuation'. Kinds or species are presupposed, not themselves stated. In the words of Aristotle: they are not open to contrariety (Categoriae 3b24, Loux 7, II p. 239ff.). They are the ousiai (substances) that are involved: For an ousia is an entity that is not predicated of another, but of which others are predicated (Categoriae 2a11, Metaphysics Z 1038b15-16; Loux p. 14: 'the idea that ousia function analogous to a kind term seems to underlie one important (in the Categories, certainly, the most important) use of the term'). Indeed, the following argument appears to rely on Aristotle himself: Even that some x is of the kind K is a predication. In a wide sense, (there is a K, x) is indeed a predication: there is a certain 'this' which is a K. The x cannot be omitted, far it is essential to distinguish a certain (K, x) from another (K, y) (Loux p. 229 and Metaphysics Z 1034a5-8). This requirement is given with the contingency that is even involved in some x's being of a certain kind. Since members of kinds come into being and pass away, they cannot be necessary of the respective kind in the last consequence. In the context of Aristotle's Metaphysics Z: ... because we want to accomodate the fact that the familiar particulars of the Categories [i.e. man or horse] can come to be and pass away, we construe them as composites of matter and form (Loux p. 160). From this point of view, however, to be of a certain kind is to have some contingent properties. The according modal logic will have to underlie intensional concepts like mass-points and natural numbers in order to determine counterparts of the respective parcels of matter. To transform such a contingent form- into a species-predication amounts to the suggestion: 'this time, I do not want to talk about the form K an x has, but rather about the form F a certain (K, x) has'. That is not to be confused with arbitrarily inventing necessary predications. In some cases, there may be no sense in talking of a certain (K, x). Aristotle himself seems to have a firm grasp of 'right' and 'wrong' species-predication: the predicates of being a man or being a horse can be said to be ousiai , but not some artificial predicates like 'white man' (Metaphysics Z 4, 1029b28, Loux p. 274: 'We have to know, for example, that man is a genuine substance sortal and that cloak [to be defined as 'white man'] is not; that geraniums are ousiai and that hoplites are not'). III. Further, I think that a tracing-principle for states of affairs contributes to a problem that Davidson poses in the context of a reconstruction of action-descriptions (Handlung und Ereignis, p. 165ff.). The according paper, The Logical Form of Action Sentences, was first published by Nicholas Rescher in 'The Logic of Decision and Action', University of Pittsburgh Press 1967. Davidson remarks that an action can be described by different sentences and asks, how it could be justified, that two such sentences deal with the same state of affairs. In contrast, Davidson sees no such problem in denoting a certain thing and then predicating various properties of this very thing. His example: 'There is a house such that I bought it, it is situated in the city, it has four bedrooms,...'. Given a complete and unique counterpart relation for states of affairs, there seems to be no problem either: a state of affairs can be denoted under all possible circumstances. Second, there need not be any worry about substitution of involved particulars salva veritate: this is only relevant for stating the belief of the agent, not for denoting the state of affairs. For belief contexts, Cresswell has given a rather complete approach in his 'Structured Meanings', Cambr. Mass./ London 1985. Towards a CalculusSince Gupta's calculus is a kind of restriction of Bressan's, it is convenient to return to the latter one. So I will allow counterpart-relations for predicates and relations, that is, for states of affairs. Since intentions are had in the actual world and can only aim at situations that can be reached in a finite number of steps, we need two things in particular:
To deal with conditional intentions we might have to label a related possible world s as 'supposed' real world sr. That is, if we want to deal with the schema 'After I have reached goal G1, I want to get G2', we have to suppose as a starting point the situation srin which G1 is reached. It might be impossible to reach G2 in the actual world r. Omitting BeliefFirst, I want to consider the distinction between 'to belief X' and 'to hope that X' that Stekeler-Weithofer draws. Davidson has pointed out, that it is possible to intend something without being sure about ones ability to bring it about (Davidson p. 141). Therefore, a belief of the form 'I can bring X about' may be too strong. Whereas it is not intelligible to intend X, but to belief that one cannot bring it about, it seems possible not to belief that one can bring it about. A Fragment of Intensional LogicThis is roughly how I suggest to proceed:
Syntax(1) It seems plausible to describe the situation r in terms the intending person can take into account. Most of the individuals can be denoted by constants. For a start, only one-place predicates will be considered, but the language can be easily extended to n-place predicates. A predication like F(c) will be called 'atomic'. To keep things simple, descriptions can also be assigned to sets of agents. The criterion for gathering agents in sets may be their social position, which can be determined by typical actions. As a result, the description need not be in terms of beliefs of a single agent, and restrictions concerning the knowledge and linguistic competence of particular persons can be relaxed. (2) The decision whether an atomic predication is substantial or not is not an arbitrary one: it may be wrong. It need not arouse too much suspicion, for it is as easy or maybe as deceptive as describing the situation r. For particular (groups of) persons, only those predications need to be regarded as changeable which the considered person can be involved in changing. Both the set of atomic predications and the assignment of a subclass of substance-predications is called description.
An atomic disposition should contain no variables. In some cases, the variables may be identified with a constant. For complex form-predications, a quantifier will be introduced together with a substance predicate. (3) Both complex form-predications and complex substance-predications are introduced. There are four kinds of complex substance-predications, and perhaps some of them should not be allowed.
The decision between substantial predications and changeable ones seems to have to be made once again. But the terms K1(x) ... Kk(x) are already given, and F(K1(x1) ...Kk(xk)) should be substantial when it holds in r. If it is true, it has to be a substance-predication. Likewise, 'not C' and 'C and D' could be defined as complex terms where C and D are terms. There may be, however, some doubts about 'not C'. I introduce it, because together with 'C and D' it allows to define other complex terms like 'not (C implies D)' or 'C or D'. Perhaps the doubts concerning negation can be countered with a lattice theoretical construction. For instance, Balzers descriptions (internal models) consist mainly in a propositional space < P, *-* > (where *-* is an informal notion of entailment or implication) and a representation of believed causal relations verursacht (i.e. 'to cause'). The propositions are fitted with a 'minimal formal structure', that contains parts of propositional logic. They seem to amount to our atomic predications. Balzer uses lattice theory to proceed in defining the infimum(p, p') and suprenum(p, p') of two propositions p, p' according to *-* (Balzer p. 94ff). After the infimum over all propositions is set 0 and the suprenum over all propositions 1, a proposition q is defined as the negation of p iff the infimum(p,q) = 0 and suprenum(p,q) = 1. As an alternative, negation could be defined as p *-* 0 = not p. There remain difficulties, however, in determining a linear order of the type *-*. In the case of mere form-predications, the things are more easy:
The other functors are introduced as usual. Semantics(4) A related situation contains every substance-predication and either every disposition or its negation. The difference to Carnaps notion of a state-description (Meaning and Necessity, Midway reprint 1988, p. 9) is the limit on dispositions. Another difference will be, that there can be individuals that do not exist in r. It will be useful (a) to consider only relevant predications and (b) to keep most of them substantial, that is, not to be changed. For every particular intention, there will naturally be such fixed values, for it is more intelligible to intend one change at a time. At least, it is impossible to intend everything to be changed, since then no understandable description of the intended state could be given. Aristotle, Metaphysics Z 8, points out that a change can only take place when both matter and form keep constant and change their mutual relations. As an abbreviation, the set of variables or canstants x1 ... xm is set to x1-m. There are two possibilities of varying the dispositions of a situation r. (5) If K(c) is a substance-predication, every counterpart of c is an x such that K(x). If F(c) or F(K(c)) is a form-predication (where K(c) is a term), to assign a counterpart means roughly to determine which other individuals can possibly be an F(x). It seems natural to take, e.g., the counterpart of an empty cup to be a filled cup, the counterpart of a woman a mother of twins. But in case of intentions, the things are different. The object of an intention is not a filled cup, but rather the filling of a cup. Therefore, it must be asked whether some actual dicta could involve another (possible) individual. This is rather clear for intentions like the one 'to care for a yet unborn child': there is no individual in r that has the child as its counterpart. The solution Bressan and Gupta give, that is, to construe an artificial nonexisting entity *, seems to be suspicious, for the silliest things might be the counterpart of * in r in some related situation s. The nonexisting entity therefore must not be 'completely' nonexisting. In the case of the unborn child, it may be required that a certain woman is in trouble. To avoid impossibilities that are imposed with such a restriction, there can be labeled a related world sr, that can be reached by other means and contain the predication in question. It is obvious that the number of involved individuals cannot keep constant for every related situation, for living beings simply have the ability to breed, and other entities can be supposed to multiply, too (for instance, the books in my room). The possible predications are nevertheless determined by 'actual possibilities', that is, dispositions in r. Time As an addition, time may be required, for intentions always aim at the future. The related situations s1, ... , sn can be ordered by a temporal relation <t, such that < S, <t > will be a linear order of situations si in S. For the real situation r, it must be supposed that there is no s in S that obtains at the same time. That is, the relation must be r <t s for every s. Interpretation In this approach both states of affairs and individual things will be assigned to predications.
Alternatively, a further distinction can be drawn between form-predications that denote changeable things, and other form-predications that denote states of affairs. I did not pursue this point. Tracing states of affairsThere are mainly three possibilities to trace a state of affairs: The example of A, who wants to have a white marriage, can be dealt with in the following way: In western countries, the existence of several institutions is necessary in order to have a white marriage. That are the church, a registry office, witnesses and the like. In the relevant situations, these institutions are not called into question, that is, every situation contains a predication like 'c is a registry officer', 'd is a priest', etc. According to Balzer, these senstences can be analysed into sentences like 'c has the social task of doing X1' (Balzer p. 74, cf. also Tuomela, The Importance of Us, p. 35 and 174. Certainly, there can be agents who want to abolish all these institutions, but the situations that are taken into account by A have to contain the according predications. The intention to have a white marriage should not be formulated like 'I want to have a white marriage when there are still the relevant institutions'. Such an intention content would be as strange as 'A bintends (X if he doesn't change his mind)' (Davidson p. 141). In contrast, an agent who strongly wants a white marriage will do the relevant things against the abolishment of the according institutions. To conclude, the white marriage that A has in a related situation is neither the same nor a direct counterpart of some white marriage actually taking place. But it is a complex predication in virtue of relevant substances of a subset of considered situations. The according terms, again, can be 'traced'. ModalitiesSeveral different kinds of necessity can be distinguished:
The first two cases display the familiar concepts of analyticity of Quine and Kant respectively. To determine necessity by the truth in every related situation is not really the same definition as Carnap gives, for the set of 'actual possibilities' is only a subset of the 'possible actualities'. What is true in every world depends not only on the logical components, but also on (a) the decision which predications are to be taken substantial and (b) the presuppositions of a particular intention. The last concept of necessity is fairly similar to Aristotle's concept of ousia. Similar considerations will have to be made in case of possibility. The main types of modality are (1) logical modality, (2) description relative-modality (3) agent-relative modality (i.e. modality relative to a social position or group) and (4) intention-relative modality. Logical necessities (i.e. necessary states of affairs)are a subset of description-relative necessitities and need not include analytic necessity. (The decision is left open.) Description-relative necessities are a subset of intention-relative necessities. When descriptions are assigned to agents, description-relative and agent-relative necessities are the same. In all cases, the same holds for possibilities. There can be circumstances, that is, certain relations to other situations, where the description has to be changed, and thereby the description-relative modalities. Analytic necessity (of the above-mentioned kind) may also be called into questions by such changes. ResultThe phrase 'A intends X' can be rendered by: A intends S+. S+ stands for the set of related situations, that fulfill the intention. Thereby, the direct reference to a sentence in natural or formal language is avoided. Intention can be described as a mapping from the set of related situations s1 ... sn in S to the values < +, - >. S is the set of situations that are assigned to +. The group or social position of the intending agent A and his ability to achieve the intended state is reflected in the construction of the related situations s1 ... sn. The reference to an according belief can be omitted for the given reasons. As regards the driving forces of A and the consistency of his different intentions, they are included in the content of the intention. si in S1+ only if there is no driving force that is not compatible with si. The notion of a driving force is left vague. It is not possible to relate driving forces directly to some s, for they do not contain a model of the intended state. The above amouts to the claim that intentions are mainly cultural phenomena. It is supposed, that a driving force must be cultivated in order to stand plainly against an intention. This, however, is rather contained in the following consistency-clause: si in S1 + only if there is no other Sigmaj such that si is in Sj+. Here, both S1+ and S1+ are intentions of the same agent or group of agents. This can be symolized by adding a further index, as in Si(a)+. Before labeling group-specific intentions Si(a)+, however, the group-relative sets of Si(a)+ have to be determined by describing the according situations r(a). Literature
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