Arthur Prior

Chez Deleuze Albertine et la Chine sont promues au titre de mondes possibles. Une telle promotion ne trouve son statut conceptuel exact que dans la logique modale mathématisée comme celle de Prior munie des TWA de Geach, qui permet aussi de déceler chez Deleuze l'équivalent d'un modèle de Kripke.

Kit Fine has proposed a new solution to what he calls 'a familiar puzzle' concerning modality and existence. The puzzle concerns the argument from the alleged truths 'It is necessary that Socrates is a man' and 'It is possible that Socrates does not exist' to the apparent falsehood 'It is possible that Socrates is a man and does not exist'. We discuss in detail Fine's setting up of the 'puzzle' and his rejection, with which we concur, of two mooted solutions to it. (One of these uses standard, Kripkean, notions, and the other rests on work done by Arthur Prior.) We set out, and reject, the philosophy of modality underlying Fine's new solution, and we defend an alternative response to the alleged puzzle. Our solution follows the work of David Wiggins in distinguishing between the sentential operator 'It is necessary that' and the predicate modifier 'necessarily'. We briefly provide this distinction with a possible-world semantics on which it is neither a necessary truth, in some sense, that Socrates exists nor true, in some sense, that Socrates necessarily exists.

I am planning a history of the notion of philosophical nonsense and naturally difficult historical and exegetical questions have come up.  Charles Pigden has argued that the notion goes back at least as far as Hobbes and that Locke, Berkeley, Hume, Kant (on some interpretations) and pragmatists such as William James, as well as numerous Twentieth-Century philosophers make use of it.  In this ‘paper’ I put forward for general discussion such questions as whether Hobbes was the first 'nonsensicalist', whether Kant was a 'nonsensicalist' at all, which philosophers if any have considered contradictions to be meaningless and whether Wittgenstein thought that his concept of criterion could legitimately be used verificationistically.  I shall continue to add further questions as they occur to me.

Comment la mobilité du grain de beauté d'Albertine entre sa joue, son menton et sa lèvre est comme le Sextus de Leibniz à Corinthe, en Thrace et à Rome dans la différence entre l'Albertine vague et l'Albertine ambiguë qui reprend la différence leibnizienne entre l'Adam vague et le Sextus ambigu, afin qu'Alberine se situe relativement à toutes les jeunes filles qui ont mauvais genre pour illustrer la logique égocentrique d'Arthur Prior telle qu'elle est symbolisée par Patrick Blackburn.

Stimulated by T. P. Uschanov’s paper ‘The strange death of ordinary language philosophy’, I try to reach a balanced assessment of Gellner’s notorious book and also to decide where Gellner stands on the notion of philosophical nonsense.  Some of the things he says suggest that he rejects the notion but he neither clearly formulates what it would have to be nor gives much in the way of argument that there could be no such thing.  One gets the impression that when philosophers he does not like – Wittgenstein and Oxford ordinary language philosophers – use it, it is unacceptable but not necessarily when philosophers to whom he is less hostile – Russell and the logical positivists – do so.

There are passages in Wittgenstein where he compares his method to psychotherapy and one or two where he seems to suggest that the ‘patient’ has the last word on his ‘illness’ and ‘cure’.  This paper tries to take these seriously, especially in connexion with the idea that victims of philosophical confusion talk nonsense.

Philosophical accusations of talking nonsense made in a polemical spirit are bound to fail, since the only way one can effectively criticise another’s utterance is by attaching some meaning to it.  But if the other acknowledges the possibility that his puzzlement arises from his having been taken in by nonsense, then perhaps a co-operative investigation of this suggestion might be fruitful.  Indeed self-diagnosis ought in principle to be possible.  Ought it not to have happened at least once in the history of philosophy if philosophical nonsense has ever been exposed? 

But there are difficulties.  For example:
a) We must ask whether or not philosophical nonsense, when exposed as such, is supposed to lose all appearance of meaningfulness.  Either answer is problematic.
b) The acknowledged similarity of the methodology under investigation to that of psychoanalysis exposes it to many of the familiar objections to the methodology of psychoanalysis, especially those that draw attention to the misleading influence of suggestion by an authority-figure.
c) The proposal that relentless cross-questioning of a suspected nonsense-talker will eventually lead her to ‘dry up’ (if she really is talking nonsense) seems to involve a version of the so-called Socratic Fallacy.

I originally entitled this paper ‘Why are there no uncontroversial examples of philosophical nonsense?’, but since this seemed apt to provoke rather superficial responses, I decided to re-title it.  In it I ponder the fact that, not only are there no uncontroversial examples of philosophical nonsense, there are no uncontroversial examples of what one might call ‘analogue philosophical nonsense’.  These would be non-philosophical cases of someone’s believing he means something when in reality he means nothing.  (Someone’s saying, ‘It’s 5 o’clock on the sun’ is sometimes offered as an example.)  I ask what conditions such cases would need to satisfy.  What would count as a compellingly clear case of an illusion of meaning?  Why has no one described one?

I suggest that, although the nonsensicalist challenge (obviously) matters, it has, at least in its Wittgensteinian form, been widely ignored.  On the other hand, those who still adhere to nonsensicalism (mainly Wittgensteinians) have been equally remiss in their failure to examine its presuppositions.

Few would doubt that one often encounters the preposterous in philosophy.  Some would claim that preposterousness in philosophy is often a matter of literal nonsensicality, i.e. meaninglessness.  Is this plausible or is it itself an example of a preposterous philosophical claim?

Is the history of philosophy primarily a contribution to PHILOSOPHY or primarily a contribution to HISTORY?  This paper is primarily contribution to history (specifically the history of New Zealand) but although the history of philosophy has been big in New Zealand, most NZ philosophers  with a historical bent are primarily  interested in the history of philosophy as a contribution to philosophy. My essay focuses on two questions: 1) How did New Zealand philosophy  get to be so good?  And why, given that is so good (a point I am at pains to establish), has it apparently had  so slight a cultural impact within New Zealand itself?  Did we get the wrong Anderson – the uninspiring William, who was Professor at Auckland, rather than his talented younger brother John, who had such a huge cultural influence as Professor of Philosophy at Sydney?  Perhaps but that can only be part of the story since we managed to attract even bigger stars, (notably Karl Popper) as well as breeding bigger talents of our own (Prior, Baier, Bennett, Mulgan, Hursthouse, Waldron and many more).  Do we export our best talent? Sometimes – but the stars that stay and the stars who arrive don’t seem to have much impact in New Zealand itself however brightly they shine in the international philosophical firmament.  Is it too esoteric? Perhaps, but esoteric philosophy can still have a cultural impact, witness, Moore, Popper and the younger Anderson. Is it, like many of New Zealand’s cultural products (from romance novels to movies), primarily intended for an international audience? That’s a large part of the answer but only a part. Another part of the answer is that philosophy HAS had a cultural impact but that impact is not readily apparent. For NZ philosophers have been less keen to push their ideological barrows and more keen to produce critical thinkers, and critical thinkers don’t all think alike. The logician George Hughes was apparently a life-changing teacher not because he had a nostrum but because he taught people to think. As one of his students said ‘the only ism you believe in is the syllogism’.
On the whole the history of New Zealand Philosphy is a  ‘From Log Cabin to White House’ tale, ‘From colonial obscurity through struggle and adversity to philosophical excellence’. But there are shadows in the picture.  Some departments have nearly come to grief through bureaucratic and political misadventures, and it is hard to resist the suspicion that there is often an element of hostility to philosophers on the part of both university bureaucrats and fellow-academics.  I speculate as to why this is the case (we are too argumentative and don’t confine our argumentative tendencies to the cloister) but conclude with some upbeat reflections. on the future of New Zealand Philosophy.

I am planning a history of the notion of philosophical nonsense and naturally difficult historical and exegetical questions have come up.  Charles Pigden has argued that the notion goes back at least as far as Hobbes and that Locke, Berkeley, Hume, Kant (on some interpretations) and pragmatists such as William James, as well as numerous Twentieth-Century philosophers make use of it.  In this ‘paper’ I put forward for general discussion such questions as whether Hobbes was the first 'nonsensicalist', whether Kant was a 'nonsensicalist' at all, which philosophers if any have considered contradictions to be meaningless and whether Wittgenstein thought that his concept of criterion could legitimately be used verificationistically.  I shall continue to add further questions as they occur to me.

Wittgenstein's notion of passing from 'disguised' to 'patent' nonsense is problematic once one realises that nonsense can have no logical properties.  I ask whether anything has yet been demonstrated to to be disguised nonsense.  No philosophical thesis (something that has been seriously offered as a truth) has, but even invented examples turn out to be controversial.  An example from elementary algebra however does seem to show how someone could unwittingly treat as sense what was in fact nonsense.  But, although the case genuinely deserves to be called one of disguised nonsense, there is still a crucial difference from what a case of philosophical nonsense would have to be.

Considering the contemporary analytic metaphysics of time, in my paper I assume that Severino’s position amounts to a sophisticated form of dynamical eternalism akin to the so-called moving spotlight view. I argue that one of Severino’s core arguments against nihilism can be formulated – in the framework of analytic philosophy – as the objection that presentism is self-defeating. Presentism essentially claims that (1) reality is confined to the present and (2) that entities go into and out of existence over time. Thus, Severino’s objection can be formulated as follows: either the presentists, in order to maintain that some entities have gone out of existence, refer to them by singular propositions stating that these fully past entities do not exist anymore (or yet), or they fail to affirm genuine change. In the former case, such negative existential propositions necessarily turn out to be false (given that singular propositions are existence-entailing) and so does presentism itself; in the latter case, presentism fails to claim that reality genuinely changes, relapsing thus into eternalism. I consider – as possible defences of presentism – both the use of definite descriptions to talk about past entities without referring to them, and the alleged opacity of temporal operators (i.e. the negation of the temporal equivalent of the Barcan’s formula).

This paper is a bridge between my interest in the notion of philosophical nonsense and my interest in problems concerning ethics and action.  Geach sees an analogy between philosophical error and moral error, more specifically between the problem of understanding the state of mind of someone who is duped by philosophical nonsense and that of someone who ‘sins’.  In neither case does being confused oneself help one understand the confusion of others.  I argue that Geach gives us no good reason to believe that there is such a thing as philosophical nonsense and that, even if there is, there will be no real analogy between the states of mind in question.  For one thing, there is no obvious reason why there could not be ‘clear-headed sin’.  For another, one who ‘sins’ and one who does not often have the same sorts of difficulty understanding each other, whereas, if there is such a thing as philosophical nonsense, it is hard to see how there could be any such symmetry between one who is taken in by it and one who is not.

In this paper I revisit the debate about tense-versus tenseless theory, or A-versus B-theory. Canonically, Arthur Prior's seminal paper Thank Goodness That's Over is said to have triggered the switch from the old to the new B-theory. I argue that Moritz Schlick made the case for indispensable A-sentences 25 years prior to Prior. More precisely, I assert that both philosophers support the same theses: 1) A-notions are indispensable and 2) A-sentences are not in general translatable into B-sentences. While this is the case, Schlick's argument is based in a very different context than Prior's and also Schlick's reasons for holding 1) differ from Prior's. Therefor it is questionable whether Schlick's paper could have had the same influence that Prior's paper had.

I will show how a metaphysical problem of Arthur Prior's can be solved by a logical tool he developed himself, but did not put to any foundational use: metric logic. The broader context is given by the key question about the metaphysics of time: Is time tenseless, i.e., is time just a structure of instants; or is time tensed, because some facts are irreducibly tensed? I take sides with Prior and the tensed theory. Like him, I therefore I have to deal with a more specific metaphysical question: How can the instants of tenseless time be reduced to tensed facts? This is the point where, on the technical level, hybrid logic and metric logic come in. For present purposes, both can be seen as species of tense logic; and both are creations of Prior. In his argument for the tensed theory of time, Prior used hybrid tense logic to reduce instants. But, as he himself pointed out, this reduction runs into deep problems, because it immediately generalizes to other categories, for example and most importantly to persons. My main aim is to show that metric logic does not run into similar difficulties: It will help the tensed theory reduce instants, but it leaves persons untouched. I will also give reasons for preferring a metric to a hybrid logic of time that are independent of the metaphysical issue of reduction, but concern temporal reasoning, natural language semantics, and the epistemic side of time-keeping.

Suppose that our world is objectively indeterministic, so that at certain points in time, there is more than one way in which events might carry on. Two main positions address how to think about the future as it unfolds beyond such indeterministic points in time: the Thin Red Line (TRL) approach which holds that among possible future courses of events, exactly one of them is what will happen; and the Open Future (OF) approach which denies this posit of a privileged course of events. OF is often associated with the view that future contingents (statements concerning future events whose truth value is not guaranteed by physical, metaphysical, or logical necessity) are neither true nor false. This “truth-value gap” commitment has in turn been thought to produce unpalatable implications concerning the practice of assertion: (1) Some have denied that it is possible to assert a future contingent when that statement’s propositional content lacks truth value at the time of its utterance; (2) others have denied that one can appropriately assert a future contingent when its propositional content cannot be known to be true at the time of its utterance. In response to (1) I argue that a sentence can have truth conditions, and thus a determinate content, even if it lacks truth value at its time of utterance. Because it is contents (rather than truth-valued contents) that are needed for viable speech acts, I conclude that OF can readily accommodate assertions of future contingents. In response to (2) I argue that even if we accept the “knowledge norm” for assertion that drives this objection, that norm does not mandate a reading on which assertions of future contingents must violate it on OF. The upshot of our response to these two objections to OF is that the contest between it and TRL should be settled, if at all, on other grounds than those pertaining to the pragmatic and epistemological aspects of assertion of future contingents.

I am planning a history of the concept of philosophical nonsense and naturally difficult historical and exegetical questions have come up.  Charles Pigden has argued that it goes back at least as far as Hobbes and that Locke, Berkeley, Hume, Kant (on some interpretations) and pragmatists such as William James, as well as numerous Twentieth-Century philosophers make use of it.  In this ‘paper’ I put forward for general discussion such questions as whether Hobbes was the first nonsensicalist, whether Kant was a nonsensicalist at all, which philosophers if any have considered contradictions to be meaningless and whether Wittgenstein thought that his concept of criterion could legitimately be used verificationistically.  I shall continue to add further questions as they occur to me.

Arthur Prior made considerable contributions to logical theory in the middle of the twentieth century.  He is generally credited with being the founder of temporal logic, and he was also closely involved with the development of operator theory, which enabled analyses to be formulated of intensional constructions like ‘It is believed that p’.  But his operator theories, as we shall see, blocked him from developing theories of causation, and thereby a fuller account of the logic of time.  In this paper I develop a tense logic allowing for causation, but the logic necessarily lacks the branching time models that Prior found necessary in his approaches to time.  I do so by adding to Prior’s metric tense axioms for linear time a formulation of causal remarks like ‘that p brought it about that q’.  So a relational structure gets added to linear time.  The general idea is that, in addition to the progress of time, it is possible to discriminate what causes what, although there is no requirement that every event does have a cause, allowing the progress of time to be in places indeterministic.  A major disappointment for some, though, is that causal relations are particular, and so the resultant account of possibly indeterministic time does not lead to much calculation, or the proof of many further theorems, as in Prior’s and similar analyses. Specifically analyses of causation in terms of conditionals are ruled out, since ‘that q brought it about that p’ is not of the form ‘q → p’ for any ‘→’.

This paper is a bridge between my interest in the notion of philosophical nonsense and my interest in problems concerning ethics and action.  Geach sees an analogy between philosophical error and moral error, more specifically between the problem of understanding the state of mind of someone who is duped by philosophical nonsense and that of someone who ‘sins’.  In neither case does being confused oneself help one understand the confusion of others.  I argue that Geach gives us no good reason to believe that there is such a thing as philosophical nonsense and that, even if there is, there will be no real analogy between the states of mind in question.  For one thing, there is no obvious reason why there could not be ‘clear-headed sin’.  For another, one who ‘sins’ and one who does not often have the same sorts of difficulty understanding each other, whereas, if there is such a thing as philosophical nonsense, it is hard to see how there could be any such symmetry between one who is taken in by it and one who is not.

In a recent article, Hofweber (2019) presents a new, and surprising, argument for idealism. His argument is surprising because it starts with an apparently innocent premise from the philosophy of language: that 'that'-clauses do not refer. I do not think that Hofweber's argument works, and my first aim in this paper is to explain why. However, I agree with Hofweber that what we say about 'that'-clauses has important metaphysical consequences. My second aim is to argue that far from leading us into idealism, denying that 'that'-clauses refer is the first step toward a kind of direct realism about belief.

A côté de la logique mathématique une logique philosophique s'est constituée, où les derniers pas principaux sont, dans l'ontologie triadique de Dana Scott, la Règle de Rescher et, pour un graphe de Van Benthem, le pas de Blackburn attribuant à Prior une logique à opérateur @.

Les noms de mathématiciens parmi les plus grands sont aussi des noms de philosophes. Mais le rapport entre mathématiques et philosophie qui est ainsi attesté n'a pas toujours été le même. Il est passé par trois états principaux dont il fallait faire le récit et tirer toutes les conséquences.

This paper goes naturally with my earlier paper 'The importance of Russell's Theory of Types for the emergence of twentieth-century nonsensicalism'.  In it I discuss the method Prior proposes in his paper ‘Entities’ for dealing with Russell’s Paradox without appealing to the concept of nonsense.

All’interno del dibattito che anima la filosofia temporale esistono numerose correnti di pensiero su quale posizione si debba adottare riguardo al problema del valore di verità delle proposizioni sul futuro. Nella prima parte dell’articolo verrà tracciato il quadro generale della discussione mediante una ricostruzione storica delle varie argomentazioni – da Aristotele e Diodoro Crono a Prior – e verranno analizzate le posizioni che si sono sviluppate, a partire da queste, nell’età contemporanea. Nella seconda parte invece tenterò di mostrare come la competizione fra la teoria del futuro vero e il sistema ockhamista di Prior non si basi su due differenti concetti di contingenza, ma sulla mancata distinzione, all’interno del sistema ockhamista, di due significati di ‘determinato’ e sulla conseguente confusione che investe il concetto di necessità. Una volta recuperata tale distinzione la teoria ockhamista può essere riformulata e le due diverse posizioni si rivelano essere, semplicemente, teorie sulla determinatezza degli stati futuri.
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A large number of schools of thought enliven the philosophical debate on how we can manage the truth-values of propositions about the future. In the first part of this paper I’ll draw an overall view of the discussion, proposing an historical reconstruction of the arguments – from Aristotle and Diodoro Crono to Prior – that will give us the instruments to understand the current state of the debate. After that, in the second part, I’ll argue that the discussion between theory of the true future and Prior’s ockhamist theory is not based on two different concepts of contingency, but instead on the lack of distinction between two different meanings of ‘determined’ inside the ockhamist system. Recovering this distinction is the first step to understand that the real competition between the two systems is not about contingency, but only about the determination of the future.

Arthur Prior’s logic was influenced, among others, by logicians from the Lvov-Warsaw school. This paper introduces the impact Leśniewski’s Ontology had on Prior’s logical system. The paper describes the main characteristics of Leśniewski’s Ontology, Prior’s logical system and the manner in which Prior became acquainted with Leśniewski’s logical system. Since Leśniewski was no longer alive when Prior began to develop his logical system and Leśniewski’s papers were not easily available to Prior, this paper also includes Prior’s interpretation of Leśniewski’s logical system which did not always correspond to Leśniewski’s original ideas.

If God’s omniscience entails knowing all things, including those that did not occur yet, how is it possible that humans act freely? This very much discussed old question had a sudden revival with Nelson Pike’s paper fifty years ago. In this paper we provide an analysis of the argument for “theological fatalism” under the light of some assumptions about the structure of time and the semantics of tensed sentences.
We present, in particular, Prior-Thomason semantics for indeterminist time (second section). This semantics motivates the distinction between time of evaluation and perspective which, we argue, is required for the definition of an appropriate truth-predicate in the context of tensed discourse. Third section shows how the previous language and semantics can be used to formalise the argument for theological fatalism. The argument turns out to be valid and we argue that the only way left for a compatibilist solution makes essential use of the distinction between time of evaluation and perspective which was independently motivated in the previous section. We included an appendix with precise definitions and some examples. The first section explains the argument for theological fatalism.

Russell decided that the only way to avoid the paradox that bears his name was to reject certain combinations of words that were apparently about classes as being in fact nonsensical.  In doing this he was not accusing some rival school of philosophers of talking nonsense; only his own previous self.  This gave his position an air of non-polemical neutrality.  So long as no alternative was known to his treatment of the matter, it looked as though he had DISCOVERED that seemingly meaningful, well-formed sentences could be in reality nonsensical.  In spite of the fact that Russell made only a limited use of this idea in his own philosophy, I argue that he gave a decisive impetus to nonsensicalism by providing what seemed to be a museum exhibit of philosophical nonsense.

Comment l'Analogie de Borges entre les Moi, les Mondes et les Temps offre le caravansérail où la caravane conduite par Deleuze peut rencontrer la caravane conduite par Prior, en déployant pour le Concept (i) ses trois composantes, (ii) son histoire et (iii) son devenir.