The A Priori

With the discovery of consistent non-Euclidean geometries, the a priori status of Euclidean proof was radically undermined. In response, philosophers proposed two revisionary interpretations of the practice: some argued that Euclidean proof is a purely formal system of deductive logic; others suggested that Euclidean reasoning is empirical, employing concepts derived from experience. I argue that both interpretations fail to capture the true nature of our geometrical thought. Euclidean proof is not a system of pure logic, but one in which our (...) grasp of the content of geometrical concepts plays a central role; moreover, our grasp of this content is a priori. (shrink)

Three classic distinctions specify that truths can be necessary versus contingent,analytic versus synthetic, and a priori versus a posteriori. The philosopher reading this article knows very well both how useful and ordinary such distinctions are in our conceptual work and that they have been subject to many and detailed debates, especially the last two. In the following pages, I do not wish to discuss how far they may be tenable. I shall assume that, if they are reasonable and non problematic (...) in some ordinary cases, then they can be used in order to understand what kind of knowledge the maker’s knowledge is. By this I mean the sort of knowledge that Alice enjoys when she holds the information that Bob’s coffee is sweetened because she just put two spoons of sugar in it herself. The maker’s knowledge tradition is quite important but it is not mainstream in modern and analytic epistemology and lacks grounding in terms of exactly what sort of knowledge one is talking about. My suggestion is that this grounding can be provided by a minimalist approach, based on an information-theoretical analysis. In the article, I argue that we need to decouple a fourth distinction, namely informative versus uninformative, from the previous three and, in particular, from its implicit association with analytic versus synthetic and a priori versus a posteriori; such a decoupling facilitates, and is facilitated by, moving from a monoagent to a multiagent approach: the distinctions qualify a proposition, a message, or some information not just in themselves but relationally, with respect to an informational agent; the decoupling and the multiagent approach enable a re-mapping of currently available positions in epistemology on these four dichotomies; within such a re-mapping, two positions, capturing the nature of a witness’ knowledge and of a maker’s knowledge, can best be described as contingent, synthetic, a posteriori, and uninformative and as contingent, synthetic, weakly a priori, and uninformative respectively. In the conclusion, I indicate why the analysis of the maker’s knowledge has important consequences in all those cases in which the poietic intervention on a system determines the truth of the model of that system. (shrink)

This chapter considers Ernest Sosa’s contributions to philosophical methodology. In Section 1, Sosa’s approach to the role of intuitions in the epistemology of philosophy is considered and related to his broader virtue-theoretic epistemological framework. Of particular focus is the question whether false or unjustified intuitions may justify. Section 2 considers Sosa’s response to sceptical challenges about intuitions, especially those deriving from experimental philosophy. I argue that Sosa’s attempt to attribute apparent disagreement in survey data to difference in meaning fails, but (...) that some of his other, more general, responses to experimentalist sceptics succeed. (shrink)

Infallibilism about a priori justification is the thesis that for an agent A to be a priori justified in believing p, that which justifies A's belief that p must guarantee the truth of p. No analogous thesis is thought to obtain for empirically justified beliefs. The aim of this article is to argue that infallibilism about the a priori is an untenable philosophical position and to provide theoretical understanding why we not only can be, but rather must be, a priori (...) justified in believing some false propositions. The argument develops notions of obviousness and conceptual understanding as a means of affording insight into the conditions for having a priori justification and, consequently, into why infallibilism cannot stand. (shrink)

It is a natural assumption in mainstream epistemological theory that ascriptions of knowledge of a proposition p track strength of epistemic position vis-à-vis p. It is equally natural to assume that the strength of one’s epistemic position is maximally high in cases where p concerns a simple analytic truth. For instance, it seems reasonable to suppose that one’s epistemic position vis-à-vis “a cat is a cat” is harder to improve than one’s position vis-à-vis “a cat is on the mat”, and (...) consequently, that the former is at least as unambiguous a case of knowledge as the latter. The current paper, however, presents empirical evidence which challenges this intuitive line of reasoning. Our study on the epistemic intuitions of hundreds of academic philosophers supports the idea that simple and uncontroversial analytic propositions are less likely to qualify as knowledge than empirical ones. We show that our results, though at odds with orthodox theories of knowledge in mainstream epistemology, can be explained in a way consistent with Wittgenstein’s remarks on ‘hinge propositions’ or with Stalnaker’s pragmatics of assertion. We then present and evaluate a number of lines of response mainstream theories of knowledge could appeal to in accommodating our results. Finally, we show how each line of response runs into some prima facie difficulties. Thus, our observed asymmetry between knowing “a cat is a cat” and knowing “a cat is on the mat” presents a puzzle which mainstream epistemology needs to resolve. (shrink)

Michael Devitt has been developing an influential two-pronged attack on the a priori for over thirteen years. This attack does not attempt to undermine the coherence or significance of the distinction between the a priori and the a posteriori, but rather to answer the question: 'What Can We Know A Priori?' with: 'Nothing'. In this paper I explain why I am dissatisfied with key extant responses to Devitt's attack, and then take my own steps towards resisting the attack as it (...) appears in two recent incarnations. Devitt aims firstly to undermine the motivation for believing in any a priori knowledge, and secondly to provide reasons directly against believing in any. I argue that he misidentifies the motivations available to the a priorist, and that his reasons against believing in the a priori do not take account of all the options. I also argue that his attempt to combine the two prongs of the attack into an abductive argument for his anti-a priorist position does not succeed. (shrink)

How is knowledge of the external world possible? How is knowledge of other minds possible? How is a priori knowledge possible? These are all examples of how-possible questions in epistemology. In this highly original book Quassim Cassam explains how such questions arise and how they should be answered.

The topic of a priori knowledge is approached through the theory of evidence. A shortcoming in traditional formulations of moderate rationalism and moderate empiricism is that they fail to explain why rational intuition and phenomenal experience count as basic sources of evidence. This explanatory gap is filled by modal reliabilism -- the theory that there is a qualified modal tie between basic sources of evidence and the truth. This tie to the truth is then explained by the theory of concept (...) possession: this tie is a consequence of what, by definition, it is to possess (i.e., to understand) one’s concepts. A corollary of the overall account is that the a priori disciplines (logic, mathematics, philosophy) can be largely autonomous from the empirical sciences. (shrink)

In recent years, Reichenbach's 1920 conception of the principles of coordination has attracted increased attention after Michael Friedman's attempt to revive Reichenbach's idea of a "relativized a priori". This paper follows the origin and development of this idea in the framework of Reichenbach's distinction between the axioms of coordination and the axioms of connection. It suggests a further differentiation among the coordinating axioms and accordingly proposes a different account of Reichenbach's "relativized a priori".

Originally published in 1966, this pivotal work of Mikel Dufrenne revises Kant’s notion of _a priori,_ a concept previously given insufficient attention by philosophers, to realize a rich understanding that finally does justice to one of Kant’s most troubling cruxes. Following the Husserlian analytics of phenomenology, Dufrenne postulates a dualistic conception of the _a priori_ as a structure that expresses itself outside the human subject, but also as a virtual knowledge that points to a philosophy of immediate apprehension or feeling. (...) A friend of Paul Ricoeur, with whom he was detained as a prisoner of war during World War II, Dufrenne’s work until now has been sorely overlooked by American philosophers. (shrink)

This book is concerned with the alleged capacity of the human mind to arrive at beliefs and knowledge about the world on the basis of pure reason without any dependence on sensory experience. Most recent philosophers reject the view and argue that all substantive knowledge must be sensory in origin. Laurence BonJour provocatively reopens the debate by presenting the most comprehensive exposition and defence of the rationalist view that a priori insight is a genuine basis for knowledge. This important book (...) will be at the centre of debate about the theory of knowledge for many years to come. (shrink)

For much of the past two millennia philosophers have embraced a priori knowledge and have thought that the a priori plays an important role in philosophy itself. Philosophers from Plato to Descartes, Kant to Kripke, all endorse the a priori and engage in a priori reasoning in their philosophical discussions. Recent work in epistemology and experimental philosophy, however, has raised questions about both the existence of a priori knowledge and the centrality of the a priori for philosophy. This collection of (...) essays aims to advance the discussion of the a priori and its role in philosophy. The contributors include a mix of young and established philosophers, including some of the most prominent voices in philosophy today. (shrink)

This volume collects articles of the late philosopher Tamara Horowitz. It includes four previously published and two unpublished articles. Though she had wide-ranging interests during her career, Horowitz was mostly concerned with what can be known as priori. She argued against too much confidence in philosophical intuition and argued for a more naturalist, scientific approach. Joseph Camp includes an editor's introduction to the collection of this important philosopher.

Our typology is based on two ground adequacy factors, one logical and one epistemic. Logically, the step from premises to conclusion may be conclusive or only ceteris paribus. Epistemically, warrants may be backed a priori or a posteriori. Hence there are four types of arguments: conclusive a priori, defeasible a priori, defeasible a posteriori, and prima facie conclusive a posteriori. We shall give an example of each and compare our scheme with other typologies.

We consider, in a bounded domain Ω 1, and the function H grows at most like |Du|q+f, with p-1 (...) approach, generalizing the method introduces in our note [29]. We complete the results known in the previous literature where either q ≤ p - 1 or m ≥ N/p. (shrink)

The aim of this article is twofold. First, we shall review and analyse the neo-kantian justification for the application of probabilistic concepts in science that was defended by Hans Reichenbach early in his career, notably in his dissertation of 1916. At first sight this kantian approach seems to contrast sharply with Reichenbach’s later logical positivist, frequentist viewpoint. But, and this is our second goal, we shall attempt to show that there is an underlying continuity in Reichenbach’s thought: typical features of (...) his early kantian conceptions can still be recognized in his later work. (shrink)

In his book The Nature of Mathematical Knowledge and in a series of articles, Philip Kitcher attacks the traditional conception of a priori mathematical knowledge. The reliabilism he develops as an alternative situates all our knowledge within a psychological framework. However, in Frege‘s Epistemology he claims that Frege‘s conception of a priori knowledge is compatible with a psychological account. Kitcher attributes to Frege a traditional concept of proof, according to which mathematical and logical proofs are psychological activities. I shall argue (...) that Kitcher‘s interpretation conflicts with Frege‘s anti-psychologistic injunction against confusing reasons with causes. Moreover, the psychological explanation obscures one of the most interesting features of a priori knowledge. (shrink)

This dissertation defends an epistemology that is simultaneously naturalistic---partaking of a consistently scientific worldview---and rationalistic---admitting of the existence of a priori justification. To attain such a naturalistic rationalism , we need to acknowledge that the unconscious structure of our inferential and intuition-producing mechanisms may be relevant to the justificatory status of our cognitions. Such an acknowledgement first requires admitting a limited version of epistemological externalism, which is defended by appeal to an 'analysis-by-imagined-reconstruction'. That is, we explore our norms of justification (...) by imagining how we would re-design those norms ourselves, given our epistemic goals of diachronic reliability and dialectical robustness. These 'DR desiderata' motivate some internalist constraint on justification, to help us keep track of truths and allow us to manage our investigative disputes. But a thoroughgoingly internalist norm is of no use to us, since no agent with our limitations and psychological make-up could satisfy it. Moreover, an externalist loophole would be permissible in circumstances where the truth is stable and where agreement is guaranteed---precisely conditions that attain in many classic cases of a priori justified beliefs, such as in basic mathematical truths. The initial take on this externalist loophole proves to be slightly too broad, since obvious and unchangingly true statements like 'There have been dogs' fall under it as well. An appeal to conceptual truths to tighten that loophole is considered, but rejected as ultimately specious. Rather, in appealing to the computational structure of the underlying psychological mechanisms, we can see that some cognitions are fundamentally rational---produced by mechanisms that we could construe a cognitive engineer with our goals in mind producing just such a design. We have good scientific reason to expect that much---but nowhere near all---of our cognitive psychology does display such rational design, even though it was designed by nature's tinkerings. The resulting framework of NR is then applied to some extant debates philosophical intuitions, and it is argued that we may be legitimately skeptical of some particularly famous philosophical intuitions in both the philosophy of mind and in epistemology. (shrink)

In the First Chapter, I give an interpretation of Kant's characterization of a priori knowledge which sharply distinguishes Kant's from an innatist conception; in this way, I distinguish Kant's transcendental explanation of a prioricity from both innatist and naturalistic explanations. ;The arguments given by Kant to support his claim that we are in fact in possession of a priori knowledge rely on his criterion of a prioricity: if a truth is necessary then it must be justified a priori. I criticize (...) the criterion's failure to account for actual cases of being justified in believing necessary truths. Finally, I discuss whether Kant has arguments to show that there is a priori knowledge which are independent of the criterion. ;In the Second Chapter, I examine the similarities and differences between Kant's and Frege's conceptions of a priori knowledge. I argue that Frege, like Kant, concentrates exclusively on the ways we must justify our beliefs in certain truths . I show, however, that Frege does not have straightforward arguments to prove that we can and do know a priori any arithmetical or logical truths, and that he does not have any straightforward explanation of the a prioricity of the laws of logic. Finally, I argue that even though a priori items of knowledge play a privileged role in Frege's project, this role differs from the one that such items have in a Kantian-transcendental project. ;In the Third Chapter, I explore whether we can make sense of the notion of a prioricity and prove that there is a priori knowledge by adopting an approach to justification which differs from both Kant's and Frege's. This approach does not concentrate on the ways we must be justified, but on the actual ways we justify our beliefs. I argue that this approach faces enormous difficulties regarding a prioricity. The central difficulty is that the actual complete justification for a belief cannot be captured exclusively in propositional terms. If a belief is based on inference, practical abilities, tendencies or dispositions enter in its justification. . . . UMI. (shrink)

The focus of this dissertation is the relationship between a priori knowledge and naturalized epistemology. I consider, by way of Paul Benacerraf's essay entitled "Mathematical Truth," the incompatibility between a priori knowledge and a causal theory of knowledge. The ideas in this essay are often invoked to support mathematical empiricism. I show that Benacerraf's own argument offers no conclusive reason to accept mathematical empiricism ;The argument given in Benacerraf's essay presupposes a causal theory of knowledge. A priori knowledge is incompatible (...) with a causal theory of knowledge. We must either reject one of these or fit a priori knowledge into some other epistemic framework. I argue that we can accommodate a priori knowledge within a reliabilist framework. One matter that appears to prevent including a priori knowledge into a reliabilist framework is the subjunctive conditional invoked by Fred Dretske and Robert Nozick. What would S believe if p were false? If S would believe p anyway, then S does not know that p. This conditional is met trivially in the case of necessary truths. And necessary truths, as a class of propositions, are alleged to be knowable a priori. So it appears that a priori knowledge meets this important conditional trivially. I argue that with suitable modification, we can construct an acceptable reliabilist framework that accommodates both necessary and contingent truths. ;I provide a definition of a priori knowledge that fits into a reliabilist and "externalist" theory of knowledge. However, it could be argued that this is inadequate, that one only knows p if one has internal or "cognitive justification" for p in addition to objective justification for p. Therefore, one knows a priori only if one's objective and cognitive justification is a priori. I argue that S knows a priori if S's objective justification is a priori. More than objective justification may be required for knowledge, but no more than one's objective justification being a priori is required for that knowledge to be a priori. (shrink)