This paper discusses two broadly logical issues related to Protagoras’ measure doctrine (M) and the self-refutation argument (SRA). First, I argue that the relevant interpretation of (M) has it that every individual human being determines all her own truths, including the truth of (M) itself. I then turn to what I take to be the most important move in the SRA: that Protagoras recognises not only that his opponents disagree with him about the truth of (M), but also that they (...) hold that (M) is false simpliciter. By recognising that his opponents do not make the relativising concession he makes for them, he is forced to accept that (M) is false. I go on to argue that several other defenders of the SRA end up with a regress which is difficult to end and might not favour anti-Protagoreans. On my reading, by recognising what his opponents believe, Protagoras is barred from adding qualifiers, and the possible regress doesn’t get off the ground. I conclude with brief discussions of how Protagoras might try to avoid the result of the SRA and the argument’s role in this part of the Theaetetus. (shrink)

Free will sceptics claim that we lack free will, i.e. the command or control of our conduct that is required for moral responsibility. There are different conceptions of free will: it is sometimes understood as having the ability to choose between real options or alternatives; and sometimes as being the original or true source of our own conduct. Whether conceived in the first or in the second way, free will is subject to strong sceptical arguments. However, free will sceptics face (...) a difficulty: doubting the existence of free will might itself be problematic, whether free will exists or not. Three main considerations are offered in support of this claim. Firstly, it is said that free will sceptics confuse contexts: even if they are right to doubt the existence of free will in the philosophy classroom, they are wrong to do so in other contexts, such as day-to-day interactions or a court of law. Secondly, it is said that free will scepticism is incompatible with inescapable and indispensable human practices such as practical deliberation or moral criticism and evaluation. For, to deliberate about what to do, we must presume that we have true options or alternatives. And to judge that some human practices are wrong, we need to assume the existence of moral responsibility. Thirdly, free will scepticism is sometimes said to be self-defeating, on the grounds that it cannot be rational to believe free will scepticism, because free will is required for rationality. This thesis critically assesses these arguments. None takes free will scepticism down, but all are instructive about how not to be a sceptic. They trace the ‘contours’ of free will scepticism by discrediting some conceptions of free will and some arguments for free will scepticism. (shrink)

Interactive theorem provers might seem particularly impractical in the history of philosophy. Journal articles in this discipline are generally not formalized. Interactive theorem provers involve a learning curve for which the payoffs might seem minimal. In this article I argue that interactive theorem provers have already demonstrated their potential as a useful tool for historians of philosophy; I do this by highlighting examples of work where this has already been done. Further, I argue that interactive theorem provers can continue to (...) be useful tools for historians of philosophy in the future; this claim is defended through a more conceptual analysis of what historians of philosophy do that identifies argument reconstruction as a core activity of such practitioners. It is then shown that interactive theorem provers can assist in this core practice by a description of what interactive theorem provers are and can do. If this is right, then computer verification for historians of philosophy is in the offing. (shrink)

In the Theaetetus Socrates provides an elaboration and discussion of Protagoras’ measure doctrine, grounding it in a “secret doctrine” of flux. This paper argues that the anthropology of the myth in the Protagoras provides an earlier, very different way to explain the measure doctrine, focusing on its application to civic values, such as “just,” “fine,” and “pious.” The paper shows that Protagoras’ explanation of the dual etiology of virtue – that it is acquired both by nature and by nurture – (...) tracks the two meanings of “anthropos” in his formulation of the measure doctrine, as “humankind” and “individual human.” On Protagoras’ account, humankind’s survival can be explained by the fact that humans share shame and justice, which enables them to live together in cities. (shrink)

ABSTRACT At the centre of Plato’s Euthydemus lie a series of arguments in which Socrates’ interlocutors, the sophists Euthydemus and Dionysodorus propose a radical account of truth (‘chopped logos’) according to which there is no such thing as falsehood, and no such thing as disagreement (here ‘counter-saying’). This account of truth is not directly refutable; but in response Socrates offers a revised account of ‘saying’ focussed on the different aspects of the verb (perfect and imperfect) to give a rich account (...) of saying, of truth and of knowledge. I argue that Socrates’ response has much to offer, notably in its amplification of the process of saying and cognition, and the development of virtue. (shrink)

ABSTRACT In this paper, we build upon M.M. McCabe's [2021] characterisation of two accounts of logos and Socratic endeavour in Plato's Euthydemus. We argue that the brothers, Euthydemus and Dionysodorus, are engaged in and committed to an endeavour which has features in common with Socrates’. It has an aim, rules, and is subject to failure. It is also a unified activity in which structure, process and continuity are important. However, the brothers’ only aim is impressing their audience and they seem (...) to have no interest in knowledge, truth or the kind of moral development that Socrates values. They are also committed to very few of Socrates’ rules for conversation. Our analysis of the brothers’ project shows us that Plato presents us with an interesting problem: how we should respond to people who engage in conversation with us but with an aim that seems trivial and without the rules that we think are crucial for intellectual and moral development. (shrink)

The dialectic exhibited in Plato’s dialogues assumes different characters throughout the corpus. Nevertheless, it remains always linked to refutation. In this way, like dialectic, refutation assumes different characteristics. The aim of this work is to show how refutation takes a key role in the Sophist, even with unique features: far from facing an opponent of flesh and blood as in Socratic dialogues, the Eleatic Stranger faces hypotheses, and instead of examining consistence within the opponent’s beliefs, he draws upon a radical (...) mechanism that focuses in the conditions of possibility of the discourse. (shrink)

A fairly long (~15,000 word) overview of ancient theories of freedom and determinism. It covers the supposed threat of causal determinism to "free will," i.e., the sort of control we need to have in order to be rightly held responsible for our actions. But it also discusses fatalistic arguments that proceed from the Principle of Bivalence, what responsibility we have for our own characters, and god and fate. Philosophers discussed include Aristotle, Epicurus, the Stoics, Carneades, Alexander of Aphrodisias, and Plotinus. (...) Plato is mentioned in passing a few times in connection with other philosophers. (shrink)

An overview of the ancient philosophers and their philosophical system (divided into the fields of logic, physics, and ethics) comprising the living, organic, enduring, and evolving body of interrelated ideas identifiable as the Stoic perspective.

This paper demonstrates the central role of the Socratic elenchus in the Sophist. In the first part, I defend the position that the Stranger describes the Socratic elenchus in the sixth division of the Sophist. In the second part, I show that the Socratic elenchus is actually used when the Stranger scrutinizes the accounts of being put forward by his predecessors. In the final part, I explain the function of the Socratic elenchus in the argument of the dialogue. By contrast (...) with standard scholarly interpretations, this way of reading the text provides all the puzzles about being (241c4–251a4) with a definite function in the dialogue. It also reveals that Plato’s methodology includes a plurality of method and is more continuous than what is often believed. (shrink)

Recently, mainstream philosophy journals have tended to implement more and more stringent forms of peer review, probably in an attempt to prevent editorial decisions that are based on factors other than quality. Against this trend, we propose that journals should relax their standards of acceptance, as well as be less restrictive about whom is to decide what is admitted into the debate. We start by arguing, partly on the basis of the history of peer review in the journal Mind, that (...) past and current peer review practices attest to partisanship with respect to philosophical approach. Then, we explain that such partisanship conflicts with the standard aims of peer review, and that it is both epistemically and morally problematic. This assessment suggests that, if feasible, journals should treat all available and proposed standards of acceptance in philosophy as epistemically equal, and that philosophical work should be evaluated in terms of the novelty and significance of its contribution to developing thought in ways that are of value. Finally, we show, in a programmatic way, that improving the current situation is feasible, and can be done fairly easily. (shrink)

This is a defense of Pyrrhonian skepticism against the charge that the suspension of judgment based on equipollence is vitiated by the assent given to the equipollence in question. The apparent conflict has a conceptual side as well as a practical side, examined here as separate challenges with a section devoted to each. The conceptual challenge is that the skeptical transition from an equipollence of arguments to a suspension of judgment is undermined either by a logical contradiction or by an (...) epistemic inconsistency, perhaps by both, because the determination and affirmation of equipollence is itself a judgment of sorts, one that is not suspended. The practical challenge is that, independently of any conceptual confusion or contradiction, suspending judgment in reaction to equipollence evinces doxastic commitment to equipollence, if only because human beings are not capable of making assessments requiring rational determination without believing the corresponding premises and conclusions to be true. The two analytic sections addressing these challenges are preceded by two prefatory sections, one laying out the epistemic process, the other reviewing the evidentiary context. The response from the conceptual perspective is that the suspension of judgment based on equipollence is not a reasoned conclusion adopted as the truth of the matter but a natural reaction to an impression left by the apparently equal weight of opposing arguments. The response from the practical perspective is that the acknowledgment of equipollence is not just an affirmation of the equal weight of arguments but also an admission of inability to decide, suggesting that any assent, express or implied, is thrust upon the Pyrrhonist in a state of epistemic paralysis affecting the will and the intellect on the matter being investigated. This just leaves a deep disagreement, if any, regarding whether equipollence is an inference based on discursive activity or an impression coming from passive receptivity. But this, even if resolved in favor of the critic (which it need not and ought not be), is not the same as confusion or inconsistency on the part of the Pyrrhonist, the demonstration of which is the primary aim of this paper. (shrink)

It is well known that reductio ad absurdum arguments raise a number of interesting philosophical questions. What does it mean to assert something with the precise goal of then showing it to be false, i.e. because it leads to absurd conclusions? What kind of absurdity do we obtain? Moreover, in the mathematics education literature number of studies have shown that students find it difficult to truly comprehend the idea of reductio proofs, which indicates the cognitive complexity of these constructions. In (...) this paper, I start by discussing four philosophical issues pertaining to reductio arguments. I then briefly present a dialogical conceptualization of deductive arguments, according to which such arguments are best understood as a dialogue between two participants—Prover and Skeptic. Finally, I argue that many of the philosophical and cognitive difficulties surrounding reductio arguments are dispelled or at least further clarified once one adopts a dialogical perspective. (shrink)

An objection that has been raised to the conciliatory stance on the epistemic significance of peer disagreement known as the Equal Weight View is that it is self-defeating, self-undermining, or self-refuting. The proponent of that view claims that equal weight should be given to all the parties to a peer dispute. Hence, if one of his epistemic peers defends the opposite view, he is required to give equal weight to the two rival views, thereby undermining his confidence in the correctness (...) of the Equal Weight View. It seems that the same objection could be leveled against those who claim to suspend judgment in the face of pervasive unresolvable disagreements, as do the Pyrrhonian skeptics. In this paper, I explore the kind of response to the objection that could be offered from a neo-Pyrrhonian perspective, with the aim of better understanding the intriguing character of Pyrrhonian skepticism. (shrink)

This essay is concerned with two interrelated questions. First, a broad question: in what sense is Skepticism a philosophy− or in what sense is it “philosophy” (as we will see, these are not identical questions)? Second, a narrow one: how should we understand the process whereby ataraxia (freedom from disturbance) emerges out of epochē (suspension of judgment)? The first question arises because Skepticism is often portrayed as anti-philosophy. This depiction, I contend, surreptitiously turns a Skeptical method into a so-called Skeptical (...) doctrine which is then either condemned for being self-refuting or salvaged as a plausible (albeit odd) epistemological theory. Instead, philosophy, for the Skeptics, is a matter of practice. Skepticism is not so much a philosophy that has a worldview to proclaim as it is a philosophy that invites us to perform something. (shrink)

The inclusion of De astrologia in the Lucianic corpus has been disputed for centuries since it appears to defend astrological practices that Lucian elsewhere undercuts. This paper argues for Lucian’s authorship by illustrating its masterful subversion of a captatio benevolentiae and subtle rejection of Stoic astrological practices. The narrator begins the text by blaming phony astrologers and their erroneous predictions for inciting others to “denounce the stars and hate astrology” (ἄστρων τε κατηγοροῦσιν καὶ αὐτὴν ἀστρολογίην μισέουσιν, 2). The narrator assures (...) readers that he, the knowledgeable astrologer, will correct for the “stupidity and laziness” (ἀμαθίῃ καὶ ῥαθυμίῃ, ibid.) that bring about false predictions. The narrator’s credibility quickly decays when he attempts to recast Orpheus, Bellerophon, Icarus, Daedalus, and a host of other mythological figures as Greek astrologers. Lucian’s audience would expect such far-fetched interpretations of myth from the stereotypical Stoic philosopher, a character lampooned elsewhere in the Lucianic corpus. (shrink)

Philosophy has four forms: wonder, faith, doubt and scepticism. These are not separate categories, but separate ideal possibilities. Modern academic philosophy has fallen, for several centuries, into an error: which is the error of supposing that philosophy is only what I call doubt. Philosophy may be doubt: indeed, it is part of my argument that this is undeniably one element of, or one possibility in, philosophy; but doubt is only one of four points of the compass. In this essay I (...) indicate the nature of each point of the compass as it has been found in the history of philosophy. (shrink)

Pyrrhonism was one of the two main ancient skeptical traditions. In this second paper of the three‐part series devoted to ancient skepticism, I present and discuss some of the issues on Pyrrhonian skepticism which have been the focus of much attention in the recent literature. The topics to be addressed concern the outlooks of Pyrrho, Aenesidemus, and Sextus Empiricus.

Stanford Encyclopedia of Philosophy article.

In his refutation of skepticism in book IV of De rerum natura, Lucretius uses argumentative methods typical of Epicurus: the περιτροπή is in many ways similar to that used by the philosopher in book XXV of Περὶ φύσεως, the same book where, in a passage dedicated to the criticism against determinists, can be found a reference to the criterion of the πρόληψις, that Lucretius exploits in his refutation. Moreover, Lucretius develops a strong demonstration concerning the irrefutability of αἴσθησις as a (...) criterion of truth, which finds significant points of contact with a large fragment, transmitted by Diogenes Laertius and generally traced back to the Canon of Epicurus. The last argument used by the poet is a pragmatic one: for the skeptic it would be impossible to live. The argument is similar to the praxis-based argument used by Epicurus in the Περὶ φύσεως against the partisans of determinism. But the pragmatic argument goes back to a very ancient layer of anti-skeptical polemics, even prior to Epicurus and already present in book Γ of Aristotle’s Metaphysics. Although later influences cannot be excluded, Lucretius appears to be a faithful witness of Epicurus. Probably in a lost section of the Περὶ φύσεως, the philosopher of Samos showed positions going against skeptical or proto-skeptical attitude, contemporary or earlier to the time of the philosopher, probably developed in a Democritean or a Socratic context. Epicurus’ ad hominem strategy is very close to that of the philosopher in the Principal Doctrines XXIII–XXV, and certainly follows Aristotle’ strategy in book Γ of Metaphysics against those who deny the principle of non-contradiction. In a similar way, Epicurus does not have one figure as the objective of his refutation but constructs a hypothetical dialectical opponent capable of embodying a series of philosophical tendencies judged by the founder of Kepos to be extremely dangerous not only for the correct exercise of thought but for the human being’s life itself. (shrink)

Kazimierz Ajdukiewicz understands skepticism as the thesis that there is no criterion of truth and that the justification of any thesis is impossible. According to Ajdukiewicz, a typical skeptic confuses two levels of justification: the first order justification of a proposition s and the second order justification of the proposition that s is justified. However, the first-order justification is possible without second-order justification. This argument presented by Ajdukiewicz in 1923 heralded the epistemic externalism concerning justification developed by Alvin Goldman in (...) 1980 and the externalist response to skepticism developed by F. Dretske and M. Williams. They all suggested weakening the traditional concept of justification and concluded that if we accept the possibility of justification without self-justification, the skeptical regress is blocked. However, such a response to skepticism is dependent on the externalist notion of justification. Ajdukiewicz had opportunity to use the stronger argument from self-refutation, but he underestimated its utility. The other side of Ajdukiewicz’s relation to skepticism is his radical conventionalism that presupposes some moderate form of skepticism in a broad sense. The article is an attempt to determine what kind of skepticism Ajdukiewicz accepted and what kind he rejected. The conclusion is that Ajdukiewicz is an anti-skeptical fallibilist. (shrink)

While defending the principle of non-contradiction in Metaphysics 4, Aristotle argues that the Measure Doctrine of Protagoras is equivalent to the claim that all contradictions are true; given all appearances are true (as the Protagorean maintains), anytime people disagree we get a true contradiction. This argument seems clearly invalid: nothing guarantees that actual disagreement occurs over every matter of fact. The argument in fact works perfectly, I propose, because the Protagorean view falls prey to a version of Fitch's “paradox” of (...) knowability. The proposed reading shows how Aristotle treats the Protagorean view at issue as an epistemic theory of truth distinct from the mere claim that all appearances are true (which other opponents put forward on different grounds) and reveals Aristotle's underlying concern with the modal collapse of possibility into actuality. The revised Protagorean view Aristotle confronts in a subsequent chapter is furthermore best understood as an attempt to avoid this Fitch-style result. (shrink)

A self-fulfilling fallacy (SFF) is a fallacious argument whose conclusion is that the very fallacy employed is an invalid or otherwise illegitimate inferential procedure. This paper discusses three different ways in which SFF’s might serve to justify their conclusions. SFF’s might have probative value as honest and straightforward arguments, they might serve to justify the premise of a meta-argument or, following a point made by Roy Sorensen, they might provide a non-inferential basis for accepting their conclusion. The paper concludes with (...) an assessment of the relative merits of these proposals. (shrink)

The article studies two texts closely linked to each other. In the first place, the final lines of Physics I 2, a text in which Aristotle offers a refutation against positions that propose to modify the language to adapt it to a monistic semantics that, from his point of view, involves a reduction of the senses of being analogous to that of the Eleatic thinkers that he has been criticizing. Second, the refutation that the Eleatic Stranger offers to the linguistic (...) monists who “deny the possibility of saying one thing through another” in Plato’s Sophist 251a-254e. It is particularly interesting to illuminate the link between such passages in order to exhibit not only important points of contact in their respective positions regarding the relationship between being and language, but also some significant differences in terms of the doctrines each one of them point to, which denotes a rich and extensive discussion held at the time around the problem of unity and multiplicity in their relationship with language. (shrink)

Following the lead of Duncan Pritchard’s “Wittgensteinian Pyrrhonism,” this paper takes a further, comparative and contrastive look at the problem of justification in Sextus Empiricus and in Wittgenstein’sOn Certainty. I argue both that Pritchard’s stimulating account is problematic in certain important respects and that his insights contain much interpretive potential still to be pursued. Diverging from Pritchard, I argue that it is a significant and self-conscious aspect of Sextus’ sceptical strategies to call into question large segments of our belief systemen (...) masseby exposing as apparently unjustifiable fundamental propositions which are closely related in their linchpin role to Wittgenstein’s hinge propositions. In the first instance, the result is a more complex account of both a deeper affinity between Wittgenstein’s approach to hinge propositions and Sextus’ approach to what I termarchaipropositions and a divergence between the two. In the second instance, I suggest how the comparison withOn Certaintycan be illuminating for the interpreter of Sextus. In particular, it can help us to see how the Pyrrhonist’s everyday conduct—common assumptions to the contrary notwithstanding—involves rational procedures of justification, in line with a naturalism reminiscent of Wittgenstein. Furthermore, it can help us to reflect on the Pyrrhonist’s attitude to what Wittgenstein would have called her ‘worldview’. Throughout, I suggest that the comparison with Wittgenstein is interesting, although it must be cashed out differently, not only on the interpretation—or, perhaps, strand—of ancient Pyrrhonism which has the sceptic exempt ordinary beliefs from her suspension of judgement, but also on the interpretation (or strand) which has her disavow all beliefs categorically. (shrink)

Dissoi Logoi 4.6 presents a beautiful self-refutation argument, which I analyse here, offering a different assessment of its relation to self-contradiction and the Liar paradox from the only one available in the literature.