Evan O'Donnell

Aenesidemus, the (re-)founder of Pyrrhonian skepticism, is usually said to have begun his career as an Academic skeptic before breaking away to form his own school. This assertion rests on the interpretation of the word “συναιρεσιώτῃ” as it appears in Photius’ summary of Aenesidemus’ Pyrrhonian Discourses. Despite the general acceptance of this narrative, the strength of its support is not universally agreed upon, and doubts have been raised concerning the precise meaning of συναιρεσιώτῃ. I examine the debate surrounding the word, ultimately concluding that the non-standard reading is more consistent with Photius’ probable understanding of the history of the Academy. I then examine the evidence external to Photius and conclude that this evidence speaks against the traditional narrative as well. I conclude that we have no good grounds for linking Aenesidemus to the Academy, and that, in all likelihood, no such link ever existed.

It is usually assumed that skepticism of some form—either Academic or Pyrrhonian—survived until the late second or early third century CE alongside its Hellenistic contemporaries Stoicism and Epicureanism. I argue that the historical evidence disagrees, and that we should in fact place the demise of skepticism sometime between the mid-first century BCE and the mid-first century CE. In order to establish this, I begin by defining a set of criteria by which to determine whether a philosophical tradition is living and relevant. I then measure the major skeptical figures between the first century BCE and third century CE as well as general accounts of the philosophical landscape from this time against these criteria. I find that the evidence clearly supports a far earlier loss of relevance for skepticism than the other major Hellenistic schools. This includes a consideration of Sextus Empiricus, who I conclude was almost certainly more an autodidact (qua philosopher) than a representative of a continuous skeptical tradition. Finally, I canvass some possible reasons why skepticism may have been worse suited to survive in this time period than other philosophical schools.

I argue that the five Agrippan modes (disagreement, infinite regress, relativity, reciprocity, and hypothesis) exhaust the logical possibilities for formal structures of support. This interpretation improves upon past interpretations like those of Sextus Empiricus and Jonathan Barnes by explaining the modes’ exhaustiveness and coherence. I begin by defining the concept of “alethic support” as the support an object provides to a proposition’s truth value through processes like justification, grounding, being evidence for, etc. Taking support minimally as a binary relation, I formally specify the structures of (alethic) support implied by each of the five modes and prove that they are the only such structures possible. I thus prove that any object—including any proposition—can only be supported in these five ways.

I propose to dissolve the distinction between “rustic” and “urbane” interpretations of Sextus Empiricus’ account of Pyrrhonian assent to appearances. On the traditional picture, the “rustic” takes the skeptic to have no beliefs while the “urbane” takes the skeptic to have some “everyday” beliefs. I examine the distinction in two forms. First, in the original suite of papers by Frede, Burnyeat, and Barnes, I find that aside from a few differences in English terminology choice, the three authors substantially agree on the interpretation of assent to appearances. Second, turning to the revised distinction proposed by Fine, I find that the two supposedly divergent interpretations give us pictures of the Pyrrhonist indistinguishable from each other on the basis of the skeptic’s actions or assent. The distinction dissolved, I propose a unified interpretation that expresses what I find to be the ultimate agreement between the two supposedly different camps. Finally, I turn to the question of the skeptical life and use this unified interpretation to argue that both an everyday life and an unconventional one are equally consistent with Pyrrhonian practice.

Everyone agrees that opening inquiry is often beneficial: when we begin to wonder about an important topic, or to entertain doubts about a proposition, inquiry is an appropriate and helpful response. It is usually assumed as a corollary that closing inquiry is also beneficial. I disagree, and I argue that we have no good reason to close an inquiry once it is open. In order to do so, I develop the concept of a provisional conclusion and show that these give us all the benefits usually attributed to inquiry-closing conclusions while retaining the benefits of keeping inquiry open.

The problem of the criterion, one of the classic skeptical problems, identifies a worrisome circularity in the project of choosing a “criterion” for knowledge or truth. I argue that interest in the problem has waned in recent years due to contemporary epistemologists’ commitment to the “modest anti-skeptical project,” in which the anti-skeptic is concerned to refute the skeptic only to the satisfaction of anti-skeptics, not to rebut the skeptic on their own terms. I show how the two classic articulations of the problem of the criterion (Chisholm’s and Sextus’) are neutralized by this project. I then develop a problem of the criterion that is problematic to modest anti-skeptics. Beginning from the premise that any rationally acceptable criterion must have some reason to prefer it over other possible criteria, I show that there will always be an unresolvable choice between multiple such criteria. I conclude by providing a skeptical solution to this problem that shifts our focus away from truth/knowledge and towards belief.

Global skeptics suspend judgment on all propositions, yet still claim to be able to speak to others normally. This would strike most contemporary philosophers of language as odd, since modern semantics usually takes truth to be an important part of meaning and speaking. I develop a way of assigning meaning to sentences that is consistent with global sentences. I use it for two purposes: first, to construct a test to determine whether or not any given theory is consistent with global skepticism; second, to make a normative argument for global skepticism from some important norms around dialogue.

Global expressivists are interested in giving an account of all discursive content, notably representational content, as expressive of some form of practice. Robert Brandom’s inferentialism is generally considered the most developed form of this kind of semantic theory, and it is often appealed to by global expressivists like Huw Price. I begin by developing some descriptive concerns for inferentialism stemming from rhetorical and irrational assertions. In order to provide an expressivist account of assertion that can accommodate the meaningfulness of rhetorical assertions and irrational asserters, I propose a “motivational semantics.” I develop this semantics by deflating Brandom’s inferentialist machinery. On the inferentialist’s account, every assertion can be situated in relation to the assertions that rationally imply it and that it rationally implies. On mine, every assertion can be situated in relation to the assertions that motivate it and that it motivates, where motivation is any convention (rational or otherwise) that connects one assertion to another. This allows global expressivists to give an account of meaning that does not depend on implicating every asserter in a strictly governed game of rational reconstruction.

The global skeptic, who claims to not know anything, is often met by the self-contradiction objection, which claims that if they can establish their own position then they must have knowledge of at least that conclusion. I consider a response to this problem from Francisco Sanches, a 16th-century global skeptic. Sanches’ response is unique in that it concedes the charge of self-contradiction, but argues that self-contradiction does not impede an argument for global skepticism. I first establish that Sanches’ response to the objection differs from that of ancient global skeptics. Then I reconstruct Sanches’ argument, using the underdetermination principle to show that a successful argument for global skepticism does not lead to knowledge of any proposition. Finally, I show how such an argument can be useful to a global skeptic nonetheless, arguing that, if accepted, it gives one a reason to suspend judgment on the question of knowledge.

In this paper, I propose to describe Deleuze’s theory of knowledge as set out in Difference & Repetition. First, I show that despite Deleuze’s hostility towards a knowledge-centered approach to philosophy, we should nevertheless read him as having an epistemological theory. Second, I examine Deleuze’s theory of knowledge by proceeding from a discussion of learning as a process of resolving practical problems to a discussion of Deleuze’s theory of questions. Questions, I show, express practical imperatives that set problems into motion. Knowledge, then, is a case of solution to this question via a grappling with the problems that it brings about. I end by discussing a key feature of Deleuzian knowledge: that it never answers once and for all the problems and questions from which it springs. Instead, an instance of knowledge should be understood as one possible resolution to the practical question it answers.

There is substantial scholarship concerning the origin and use of the question “quid facti” in Kant’s Transcendental Deduction. There is also substantial scholarship concerning the question in the work of Salomon Maimon, the skeptical critic of Kant. The pictures of the “quid facti” question that emerge from these two bodies of literature, however, are rather different. The goal of this paper is thus quite simple: it will compare Kant’s and Maimon’s understandings of the quaestio quid facti, cataloguing their similarities and differences. Part I will examine the broader legal context from which the terminology of the “quaestio facti” was originally taken. Using this context, part II will lay out Kant’s understanding and use of the quaestio quid facti. Part III will do the same for Maimon’s understanding and show the ways in which the latter’s skeptical use of the quid facti question was made possible by the difference between his interpretation of the question and Kant’s. Finally, Part IV will examine the extent to which Maimon’s skeptical use of the quaestio quid facti could be said to be original.

There is very little consideration in the literature of Fichte’s relationship to the skeptical question “quid facti?” as posed by Salomon Maimon. This may strike us as odd, for Fichte famously credits Maimon with “overturning the Kantian philosophy” and names him in the first sentence of the introduction to the 1794 Wissenschaftslehre as providing the impetus to set philosophy on a more certain path. Maimon felt that his “quid facti” question was a core skeptical concern for critical philosophy—saying that it formed the basis of his “new skepticism” in the manifest of his letters with Reinhold and ending both his Worterbuch and “Essay on the Progress of Philosophy” with a standalone QUID FACTI? Fichte would have read all of these works, and his concern with overcoming skepticism must have led him to consider this quid facti question. This paper will examine whether Fichte’s Wissenschaftslehre has the resources to respond to this central skeptical question. Part I will lay out the quid facti challenge as posed by Maimon, which I will interpret as a question concerning whether a feeling of necessity and universality accompanies some judgment—in Maimon’s case, empirical judgments. Part II will examine Fichte’s response to Maimon in the 1794 Wissenschaftslehre, and I will argue that Fichte responds to the quid facti question by providing a common transcendental foundation to empirical and logical/mathematical judgments (which Maimon believed to be objective)—something Kant explicitly did not do. I conclude that Fichte’s strategy succeeds in refuting Maimon’s rationalist skepticism, but that it would not refute a skeptic who did not share Maimon’s rationalist inclinations. Such a skeptic could continue to pose the “quid facti” challenge unencumbered, and I suggest that this challenge may indicate one reason why Fichte pursued more purely practical refutations of skepticism in the post-Jena period.