Time, Thought, and Vulnerability E-Book

Paulo Faria Estrella

• Herausgeber: SADAF
• Kategorie: Geisteswissenschaft
• Sprache: Englisch

Seitenzahl: 125

Veröffentlichungsjahr: 2021

Beschreibung

Time, Thought, and Vulnerability presents the results of an investigation of the conditions on which circumstanced which lie beyond the ken (let alone the control) of a reasoner may jeopardize the validity of inferences whose correctness is supposed to be evaluable on a purely a priori basis. The discussion involves a careful examination of the ongoing debate about the transparency of mental content and the accessibility of the logical form of inferences. A comparison with the debate about the vicissitudes of preservative memory in a temporalist semantics is articulated through a comparison of the arguments presented by Mark Richard and Paul Boghossian against, respectively, temporalism and anti-individualism. Finally, the inquiry is dissociated from those two theoretical frameworks (temporalism versus eternalism; individualism versus anti-individualism) in favor of a direct discussion of the postulate of transparency of logical form.

Leseprobe

Time, Thought, and Vulnerability

An Inquiry in Cognitive Dynamics The Juan Larreta Lectures 2017

Paulo Estrella Faria has a PhD in Philosophy from the Federal University of Rio Grande do Sul, Brazil. He was visiting researcher at New York University (1995), Rutgers - the State University of New Jersey (1995-6) and the Institut Jean-Nicod (2005-6). He was founder (2008) and Vice-President (2010-2012) of the Latin American Association of Analytical Philosophy (ALFAn). He is currently Professor of the Department of Philosophy at the Federal University of Rio Grande do Sul. His areas of competence are metaphysics, epistemology, philosophy of logic and language, and the history of analytic philosophy.

Faria, Paulo Estrella

Time, Thought, and Vulnerability : An Inquiry in Cognitive Dynamics. The Juan Larreta Lectures, 2017 / Paulo Estrella Faria . - 1a ed . - Ciudad Autónoma de Buenos Aires : SADAF, 2021.

Digital book, EPUB

Archivo Digital: descarga y online

ISBN 978-987-47781-3-0

1. Filosofía. 2. Epistemología. 3. Filosofía del Conocimiento. I. Título.

CDD 121

© 2017, 2021, Paulo Estrella Faria © 2021, for this edition: SADAF

Digital publishing: November 2021

SADAFwww.sadaf.org.ar

Cover design: Iñaki Jankowski | www.jij.com.ar Cover image: Luiza Estrella Editing: Recursos Editoriales

Ebook production: Libresque

isbn: 978-987-47781-3-0

Foreword

Honoured by the Argentine Society for Philosophical Analysis (SADAF) with the invitation to deliver the 2017 Juan Larreta Lectures, I took the occasion to probe into a set of interrelated problems belonging to what David Kaplan termed ‘cognitive dynamics’—a field of philosophical inquiry which deals with the conditions on which propositional contents are retained, reiterated, redeployed, modified, lost and (sometimes) retrieved. My overall aim was to try and bring together two strands in my recent work which had until then followed parallel paths in a seemingly Euclidean space, all but avoiding one another. These are the philosophy of time (concentrating on the temporalism vs. eternalism debate, hence on the very notion of a temporal proposition: a proposition whose truth-value changes with time), and the epistemology of reasoning (concentrating on the individualism vs. anti-individualism debate, hence on the very notion of a world-involving thought, specifically as that impinges upon what Paul Boghossian calls ‘the apriority of our logical abilities’). That’s why I called the first two lectures, respectively, ‘Transience’ and ‘Preservation’. In these two lectures I claim, in particular, that Mark Richard’s 1981 argument from belief retention against temporalism and Paul Boghossian’s 1989 argument from preservative memory against anti-individualism share a common structure and a crucial pair of analogous premises; that they invite analogous responses (which have actually been put forward); and that such responses fall short of fully taking the sting off the original arguments, given precisely the way they are interrelated. Put it as follows. Suppose temporalism is true; then we have a problem (Richard’s problem) about content preservation. Suppose anti-individualism is true; then we have a problem (Boghossian’s problem) about content preservation. Since I hold that both problems are real and stand unsolved (for good reason: they are, or so I will argue, strictly unsolvable), my defence of both temporalism and anti-individualism eventuates in an investigation of the varieties of conceptual (and other) losses which are the lot of creatures whose cognitive lives are such that both temporalism and anti-individualism are true of them—hence the title of the third and last lecture.

I am grateful to the audiences at SADAF for the lively discussions. Running the risk of forgetting someone (for which I apologise in advance), I single out Alberto Moretti, Diana Pérez, Eduardo Barrio, Eleonora Orlando, Federico Penelas and Sandra Lazzer, whose contributions were warmly appreciated. I hope the result does not disappoint them.

Porto Alegre, May 2018

1. Transience

Unfathomable Sea! whose waves are years,

Ocean of Time, whose waters of deep woe

Are brackish with the salt of human tears!

Thou shoreless flood, which in thy ebb and flow

Claspest the limits of mortality!

And sick of prey, yet howling on for more,

Vomitest thy wrecks on its inhospitable shore;

Treacherous in calm, and terrible in storm,

Who shall put forth on thee,

Unfathomable Sea?

Percy Bysshe Shelley, “Time” (1821)

My aim in these lectures is to bring together two strands in my recent work which up to now have travelled parallel paths, all but avoiding each other. These are the philosophy of time (concentrating on the temporalism vs. eternalism debate, hence on the very notion of a temporal proposition: a proposition whose truth-value changes with time), and the epistemology of reasoning (concentrating on the individualism vs. anti-individualism debate, hence on the very notion of a world-involving thought, specifically as that impinges upon what Paul Boghossian is wont to call “the apriority of our logical abilities”).

Both strands converge in issues of cognitive dynamics as that philosophical discipline was defined by David Kaplan almost 30 years ago: cognitive dynamics is the study of the conditions on which propositional contents are retained, reiterated, redeployed, modified, lost and (sometimes) retrieved.1

Our starting point is an examination of the central question in the philosophy of time, namely, how to think of transience.

Let’s start with a couple of definitions.2Eternalism is the thesis that for every proposition p, and every bit of time information it needed for truth evaluation, it is specified in p. Temporalism is the thesis that there are exceptions to eternalism. That is, for some proposition p, and some bit of time information it needed for truth evaluation, it is unspecified in p (equivalently: p is neutral with respect to it).

According to eternalism, then, if a proposition is once true (or false), it is always true (or false). According to temporalism, some propositions have a changing truth-value. Notice that eternalism is the most ambitious thesis, as it holds that every proposition, if it has a truth-value at all, has an unchanging truth-value, while temporalism has it that some propositions have changing truth-values.

Our first question, then, is this: are there (as Aristotle, the Stoics and the Schoolmen thought) temporal propositions, namely, propositions whose truth-value is relative to some occasion (be it that of their utterance, that of their evaluation, or yet another), which, in consequence, can be reiterated, their identity preserved, even though their truth-value (relatively to each relevant occasion) is variable? Or should every sentence whose utterance only has a truth-value relatively to some occasion be construed (as Frege and Russell held) as the expression of a propositional function in which at least one free variable (usually unarticulated in the “surface grammar”) takes as arguments instants or time-intervals?3

It is a remarkable fact that the affirmative reply to our first question has prevailed throughout the greatest part of the history of philosophy, and that only in modern times (starting, actually, in the 18th century) there has been a gradual articulation of what was to become the canonical view in Contemporary logic and philosophy: namely, the choice of the second of the previously mentioned alternatives.

Indeed, the assumption that the answer to the first question is affirmative, and that the answer is unproblematic, is distinctive of the manner in which the relations between logic and time were conceived of in Ancient and Medieval philosophy.

In De Interpretatione, Aristotle writes: “Every statement-making sentence must contain a verb or an inflexion of a verb. For even the definition of man is not yet a statement-making sentence—unless ‘is’, or ‘will be’ or ‘was’ or something of this sort is added” (17a9ss). Such explicit mention of the verbal tenses is not accidental. As Hintikka writes, “for Aristotle the typical sentences used in expressing human knowledge or opinion are not among those Quine calls eternal sentences (or even among standing sentences) but among those Quine calls occasion sentences. That is to say, they are not sentences to which we assent or from which we dissent once and for all. They are sentences to which we can subscribe or with which we must disagree on the basis of some feature or features of the occasion on which they are uttered (or written). In particular, the sentences Aristotle is apt to have in mind are temporally indefinite; they depend on the time of their utterance” (Hintikka 1973: 64).

The idea is not that the time of utterance supplies, as in Frege and his successors, the argument of a propositional function, so that “It is sunny in Buenos Aires” turns out to be, at the time I utter it, an incomplete expression of the proposition <It is sunny in Buenos Aires now> (that is, at 6 PM, November 7, 2017). Rather, the property that Hintikka calls temporal indefinition is a characteristic of a complete proposition whose truth-value changes with time.

The idea of a proposition which is in that sense temporally indefinite—the idea of a temporal proposition—and the imbrication of logic and temporality which is required to account for such propositions, make possible, for instance, to raise the problem of future contingents the way Aristotle does it in Chapter IX of De Interpretatione. As Prior remarks, the idea that a complete proposition may have different truth-values at different times sheds light on Aristotle’s conjecture that “There will be a sea-battle tomorrow” might be (because of the indeterminacy of the situation) “not yet” definitely true or definitely false: “That things might change to being true or false from not being definitely either, is certainly a more radical view than that they might change from being true to being false and vice versa, but it is not as far from this as it is from the view that the passage of time is quite irrelevant to the truth and falsehood of propositions” (Prior 1967a: 16).

The Master Argument of Diodorus Cronus is another example of the pertinence of temporal considerations for Ancient logic. Indeed, it can be understood as an attempt at clarifying, through the demonstration of the inconsistency of a set of propositions drawn from Aristotelian philosophy, the relations between time and modality. For our purposes, Diodorus’ aim (a proof by reduction of fatalism) is less important than the fact that his argument relies on an explanation of modal notions in terms of temporal propositions: everything which is past and true is necessary; possible is what is or will be true.4

In 1949 Benson Mates published a paper entitled “Diodorean Implication”, later to become a chapter of his book Stoic Logic. In the attempt to formalise Diodorus’ thought, Mates would help himself freely to expressions like ‘p at time t’. In the first chapter of Past, Present, and Future, dedicated to the precursors of tense-logic, A. N. Prior describes how Mates’ attempt encouraged him to try, alternatively, to write Fp for “It will be the case that p”, by analogy with the usual modal construction p (“It is possible that p”). The analogy raised, unavoidably, a problem for a logic which would treat tenses and temporal adverbs, by analogy with the formal regimentation of modalities, as operators whose operands are temporally (as in the modal case, modally) neutral propositions. The plurality of systems of modal logic prompted the unavoidable question: to which of these systems correspond the Diodorean definitions? This question would be the clue to the development, in the ensuing decade, of tense logic (cf. Prior 1967a: 20-31).

The privilege accorded to temporal propositions, and the interest in the study of their logical properties, is equally manifest in Stoic logic.5 As Hintikka remarks: “Virtually all the examples of singular sentences that were used by the Stoics as examples and are preserved to us seem to be temporally indefinite. What is more important, such temporally indefinite sentences are put forward by the Stoics as examples of sentences that are taken to express a complete λεκτόν (lekton). These complete assertoric lekta or in short άξιώματα (axiomata) of the Stoics are in many respects reminiscent of the ‘propositions’ that many modern philosophers postulate as meanings of eternal assertoric sentences. However, axiomata differ from propositions in that they are temporally indefinite in the same way as occasion sentences. By saying ‘writes’ one does not express a complete lekton, we are told by the Stoics, because ‘we want to know who [writes]’. Nevertheless, a sentence like ‘Dion is walking’ is said to express a complete lekton, in spite of the fact that it leaves room for the analogous question: ‘When is it that Dion is walking?’” (Hintikka 1973: 70-71).

The Stoics were thus able to talk freely about changes in the truth-value of a lekton. It comes as no surprise that, in the first attempt at a systematic reconstruction of Stoic logic by a modern logician, Benson Mates called lekta “propositional functions with a temporal variable” (Mates 1953: 132), thus misrepresenting, volens nolens, the material he was expounding. For, if “Dion is walking” is a propositional function taking as arguments instants or time-intervals, then the proposition which, each time, the utterance of such a sentence expresses is an atemporally true or false proposition—the expression of an eternal truth (or falsehood), not the transient truth (or falsehood) posited by the Stoics.

The distortion, and the anachronism, were exposed by Geach in his review of Mates’ book. “The Stoics neither had a pair of terms answering to the Peano-Russell distinction between a proposition and a propositional function, nor gave any example that could suitably be translated by an expression like ‘Socrates dies at t’” (Geach 1955: 144). Introducing that distinction would jeopardise the examples of Stoic propositional logic which reached us. For the Stoics held that

(1) If Dion is alive, then Dion is breathing; but Dion is alive; therefore, Dion is breathing

is of the form “if p, then q; but p; therefore q’”. But this form is not to be found in

(2) For any t, if Dion is alive in t, then Dion is breathing in t; but Dion is alive now; therefore, Dion is breathing now.

Hence Geach’s question: “May not the Stoics well have thought that, though the truth-value of ‘Dion is alive’ changes at Dion’s death, the sentence still expresses the same complete meaning (lekton)?” (Geach 1955: 144). As we saw, the answer to this question is affirmative.

Like Aristotle and the Stoics, Medieval logicians had no trouble in admitting transient truths, expressed by temporal propositions, and they probed systematically the logic of such propositions. In his brief overview of conceptions about time and truth in the history of logic, Prior (1957: 104) holds that the two main theses of Medieval logic concerning that were:

(i) tense distinctions are a proper subject of logical reflection;

(ii) what is true at one time is in many cases false at another time, and vice versa.

It comes as no surprise that Geach, credited by Prior with having called his attention to the relations between time and truth in Ancient and Medieval logic, should have expressed, in a review of Julius Weinberg’s book about Nicolaus of Autrecourt, the same criticism he would address, some years later, to Mates about Stoic logic: “Such expressions as ‘at t’ (pp. 168, 172) are out of place in expounding scholastic views of time and motion. For a scholastic, Socrates is sitting is a complete proposition, enuntiabile, which is sometimes true, sometimes false; not an incomplete expression requiring a further phrase like ‘at time t’ to make it into an assertion” (Geach 1949: 244).