•  388
    Bobzien’s reply to a defamatory blogpost on her essay ‘Frege plagiarized the Stoics’ in which she is accused among other things of plagiarism (!), and deliberate deception, and which contains a large number of falsehoods. (This reply is a minor contribution to the discussion of 'Frege plagiarized the Stoics', simply setting the record straight. It contains no important philosophical content whatsoever.)
  •  283
    In this 2 1/2 page piece(ling) I introduce the terms 'to maleappropriate', 'maleappropriation', 'maleappropriator', etc., for a familiar phenomenon and pattern of behaviour, following a couple of autobiographical remarks and followed by some brief suggestions about how to handle the phenomenon. That's all. (Nothing of philosophical depth here.)
  •  119
    Determinism, Freedom, and Moral Responsibility brings together nine substantial essays on determinism, freedom, and moral responsibility in antiquity by Susanne Bobzien. The essays present the main ancient theories on these subjects, ranging historically from Aristotle followed by the Epicureans, the early Stoics, several later Stoics, and up to Alexander of Aphrodisias in the third century CE. The author discusses questions about rational and autonomous human agency and their compatibility wi…Read more
  •  5006
    In this extended essay, I argue that Frege plagiarized the Stoics --and I mean exactly that-- on a large scale in his work on the philosophy of logic and language as written mainly between 1890 and his death in 1925 (much of which published posthumously) and possibly earlier. I use ‘plagiarize' (or 'plagiarise’) merely as a descriptive term. The essay is not concerned with finger pointing or casting moral judgement. The point is rather to demonstrate carefully by means of detailed evidence that …Read more
  •  765
    Stoic logic and multiple generality
    Philosophers' Imprint 20 (31): 1-36. 2020.
    We argue that the extant evidence for Stoic logic provides all the elements required for a variable-free theory of multiple generality, including a number of remarkably modern features that straddle logic and semantics, such as the understanding of one- and two-place predicates as functions, the canonical formulation of universals as quantified conditionals, a straightforward relation between elements of propositional and first-order logic, and the roles of anaphora and rigid order in the regime…Read more
  •  21
    How to give someone Horns
    History of Philosophy & Logical Analysis 15 (1): 159-184. 2012.
    This paper discusses ancient versions of paradoxes today classified as paradoxes of presupposition and how their ancient solutions compare with contemporary ones. Sections 1–4 air ancient evidence for the Fallacy of Complex Question and suggested solutions, introduce the Horn Paradox, consider its authorship and contemporary solutions. Section 5 reconstructs the Stoic solution, suggesting the Stoics produced a Russellian-type solution based on a hidden scope ambiguity of negation. The difference…Read more
  •  757
    Since Mates’ seminal Stoic Logic there has been uncertainty and debate about how to treat the term anapodeiktos when used of Stoic syllogisms. This paper argues that the customary translation of anapodeiktos by ‘indemonstrable’ is accurate, and it explains why this is so. At the heart of the explanation is an argument that, contrary to what is commonly assumed, indemonstrability is rooted in the generic account of the Stoic epistemic notion of demonstration. Some minor insights into Stoic logic …Read more
  •  753
    Intuitionism and the Modal Logic of Vagueness
    Journal of Philosophical Logic 49 (2): 221-248. 2020.
    Intuitionistic logic provides an elegant solution to the Sorites Paradox. Its acceptance has been hampered by two factors. First, the lack of an accepted semantics for languages containing vague terms has led even philosophers sympathetic to intuitionism to complain that no explanation has been given of why intuitionistic logic is the correct logic for such languages. Second, switching from classical to intuitionistic logic, while it may help with the Sorites, does not appear to offer any advant…Read more
  •  87
    ABSTRACT: English translation of the 2nd/3rd century Peripatetic Philosopher's Alexander of Aphrodisias commentary on Aristotle's non-modal syllogistic, i.e. on one of the most influential logical texts of all times. Volume includes introduction on Alexander of Aphrodisias and the early commentators, translation with notes and comments, appendices with a new translation of Aristotle's text, a summary of Aristotle's non-modal syllogistic and textual notes.
  •  914
    Stoic Sequent Logic and Proof Theory
    History and Philosophy of Logic 40 (3): 234-265. 2019.
    This paper contends that Stoic logic (i.e. Stoic analysis) deserves more attention from contemporary logicians. It sets out how, compared with contemporary propositional calculi, Stoic analysis is closest to methods of backward proof search for Gentzen-inspired substructural sequent logics, as they have been developed in logic programming and structural proof theory, and produces its proof search calculus in tree form. It shows how multiple similarities to Gentzen sequent systems combine with in…Read more
  •  101
    Analyticity, Balance and Non-admissibility of Cut in Stoic Logic
    with Roy Dyckhoff
    Studia Logica 107 (2): 375-397. 2019.
    This paper shows that, for the Hertz–Gentzen Systems of 1933, extended by a classical rule T1 and using certain axioms, all derivations are analytic: every cut formula occurs as a subformula in the cut’s conclusion. Since the Stoic cut rules are instances of Gentzen’s Cut rule of 1933, from this we infer the decidability of the propositional logic of the Stoics. We infer the correctness for this logic of a “relevance criterion” and of two “balance criteria”, and hence that a particular derivable…Read more
  •  722
    Gestalt Shifts in the Liar Or Why KT4M Is the Logic of Semantic Modalities
    In Bradley Armour-Garb (ed.), Reflections on the Liar, Oxford University. pp. 71-113. 2017.
    ABSTRACT: This chapter offers a revenge-free solution to the liar paradox (at the centre of which is the notion of Gestalt shift) and presents a formal representation of truth in, or for, a natural language like English, which proposes to show both why -- and how -- truth is coherent and how it appears to be incoherent, while preserving classical logic and most principles that some philosophers have taken to be central to the concept of truth and our use of that notion. The chapter argues that, …Read more
  • Central passages: Alexander of Aphrodisias On Fate 181–3, 189, 192, 205, Nemesius On Human Nature 105.6–106.13; Although in the first three centuries AD there were several Stoic theories of fate in circulation, only one systematic exposition of a later Stoic compatibilist theory has survived. This is found in Alexander of Aphrodisias’ On Fate, with parallels in Nemesius. These are the only sources that provide a Stoic account of that which depends on us and its relation to Stoic fate theory. Thi…Read more
  • Central passages: Plutarch, Aud. Poet. 33d, Epictetus, Enchiridion 53.1, Seneca Letters 107.10; Hippolytus, Refutation of all Heresies 1.21.2 Eleutheria was an indispensable philosophical concept in early Stoic ethics, and became central in the moral philosophy of the Roman Stoa. The Stoic notion of eleutheria has been a source of modern misinterpretation and mis‐assessment of the early Stoic theory of fate and of Chrysippus’ compatibilism. In particular, it has been illegitimately confounded wi…Read more
  • Central passages: Gellius Attic Nights 7.2; Cicero On Fate 8 11, 39–45; Plutarch On Stoic Self‐Contradictions 1055f –1056d. There are only three sources that attest undoubtedly that Chrysippus, in some way, dealt with the problem of causal determinism and moral responsibility. They report the so‐called cylinder analogy and a Chrysippan distinction of causes, and present the core of Chrysippus’ compatibilism. The discussion of these passages in this chapter shows that they fit in smoothly with Ch…Read more
  • The Idle Argument is the classical argument for fatalism and the futility of action: ‘If it is fated that you will recover, you will, regardless of whether you consult a doctor. If it is fated that you won’t recover, you won’t, regardless... Either it is fated that you will recover or that you won’t. Therefore it is pointless to consult a doctor.’ In the first part of this chapter, the sources that preserve this argument are analysed in detail, and the various ways of understanding the argument,…Read more
  • Central passages: Cicero On Fate 11–17; Alexander of Aphrodisias On Fate 208.15–21. Critics of the Stoics tried to show up an inconsistency between Chrysippus’ acceptance of divination, on the one hand, and his conception of contingency, on the other. The argument claims that, since theorems of divination connect, in a conditional, a proposition about the past with one about the future, and since the necessity of the former is transferred to the latter, future occurrences—as far as covered by di…Read more
  • Central passages: Boethius On Interpretation II 234–5; Diogenes Laertius 7.75; Plutarch, On Stoic Self‐contradictions 1055d–f; Alexander of Aphrodisias On Fate 176.14–23. In the Stoic debate over fate and determinism, the modalities played a role in a number of different contexts. Chrysippus rejected Diodorus Cronus’ modal theory because of its built‐in necessitarian consequences. He developed his own set of modal notions, which, in themselves, do not lead to necessitarianism and which secure a …Read more
  • Central passages: Cicero On Fate 20–21, 26–28, 37, On Divination I 125–6. The first argument: Chrysippus assumes as true a weak, non‐modal form of logical determinism. From this assumption he argues for the truth of his theory of causal determinism, by showing that the latter is a necessary condition of the former. This argument differs considerably from the argument for the truth of future propositions to their necessity, which Epicurus is said to have attacked. Cicero confuses the two. The sec…Read more
  • Central passages: Plutarch On Stoic Self‐Contradictions 1045b–c; 104950, 1056; Stobaeus Ecl. I 79.1–12. The physical and ontological foundations of the Stoic theory of determinism are investigated: the active principle, causation, motion, and qualitative states and how they relate to the Stoic concept of propositions. Stoic teleological determinism grows out of the basic assumptions of Stoic cosmology and is thus firmly anchored in early Stoic physics. Stoic physics stands out in antiquity not s…Read more
  • Introduction
    In Determinism and freedom in stoic philosophy, Oxford University Press. 1998.
    Methodological information and historical background: The book focuses on problems of determinism and freedom as they were conceived in antiquity, this being a necessary condition for a full understanding of the Stoic theory. The Stoic theory of determinism and freedom is central to their philosophy as a whole. The history of works on fate, determinism, and freedom from Plato to the end of antiquity is sketched. The difficulty of the fragmentary state of our sources and the lack of first‐hand so…Read more
  •  2885
    ABSTRACT: This paper serves two purposes: (i) it can be used by students as an introduction to chapters 1-5 of book iii of the NE; (ii) it suggests an answer to the unresolved question what overall objective this section of the NE has. The paper focuses primarily on Aristotle’s theory of what makes us responsible for our actions and character. After some preliminary observations about praise, blame and responsibility (Section 2), it sets out in detail how all the key notions of NE iii 1-5 are in…Read more
  •  65
    A greek parallel to Boethius' de hypotheticis syllogismis
    Mnemosyne 55 (3): 285-300. 2002.
    In this paper I present the text, a translation, and a commentary of a long anonymous scholium to Aristotle’s Analytics which is a Greek parallel to Boethius’ De Hypotheticis Syllogismis, but has so far not been recognized as such. The scholium discusses hypothetical syllogisms of the types modus ponens and modus tollens and hypothetical syllogisms constructed from three conditionals (‘wholly hypothetical syllogisms’). It is Peripatetic, and not Stoic, in its theoretical approach as well as its …Read more
  •  603
    The Combinatorics of Stoic Conjunction
    Oxford Studies in Ancient Philosophy 40 157-188. 2011.
    ABSTRACT: The 3rd BCE Stoic logician "Chrysippus says that the number of conjunctions constructible from ten propositions exceeds one million. Hipparchus refuted this, demonstrating that the affirmative encompasses 103,049 conjunctions and the negative 310,952." After laying dormant for over 2000 years, the numbers in this Plutarch passage were recently identified as the 10th (and a derivative of the 11th) Schröder number, and F. Acerbi showed how the 2nd BCE astronomer Hipparchus could have cal…Read more
  •  958
    Wholly Hypothetical Syllogisms
    Phronesis 45 (2): 87-137. 2000.
    ABSTRACT: In antiquity we encounter a distinction of two types of hypothetical syllogisms. One type are the ‘mixed hypothetical syllogisms’. The other type is the one to which the present paper is devoted. These arguments went by the name of ‘wholly hypothetical syllogisms’. They were thought to make up a self-contained system of valid arguments. Their paradigm case consists of two conditionals as premisses, and a third as conclusion. Their presentation, either schematically or by example, varie…Read more
  •  474
    Logic: The Megarics
    In Keimpe Algra & et al (eds.), The Cambridge History of Hellenistic Philosophy, Cambridge University Press. 1999.
    ABSTRACT: Summary presentation of the surviving logic theories of Philo the Dialectician (aka Philo of Megara) and Diodorus Cronus, including some general remarks on propositional logical elements in their logic, a presentation of their theories of the conditional and a presentation of their modal theories, including a brief suggestion for a solution of the Master Argument.
  •  281
    The paper presents a new theory of higher-order vagueness. This theory is an improvement on current theories of vagueness in that it (i) describes the kind of borderline cases relevant to the Sorites paradox, (ii) retains the ‘robustness’ of vague predicates, (iii) introduces a notion of higher-order vagueness that is compositional, but (iv) avoids the paradoxes of higher-order vagueness. The theory’s central building-blocks: Borderlinehood is defined as radical unclarity. Unclarity is defined b…Read more
  •  805
    ABSTRACT: Stewart Shapiro recently argued that there is no higher-order vagueness. More specifically, his thesis is: (ST) ‘So-called second-order vagueness in ‘F’ is nothing but first-order vagueness in the phrase ‘competent speaker of English’ or ‘competent user of “F”’. Shapiro bases (ST) on a description of the phenomenon of higher-order vagueness and two accounts of ‘borderline case’ and provides several arguments in its support. We present the phenomenon (as Shapiro describes it) and the ac…Read more