Kant's Criteria of the A Priori

Kant states that necessity and strict universality are criteria of a priori knowledge. Interpreting this dictum standardly and straightforwardly in respect of necessity, it is inconsistent with there being necessary a posteriori truths or contingent a priori truths (cf Kripke). This straightforward interpretation may convict Kant of understandable error (at worst) in the case of necessity, but it is so uncharitable in the case of strict universality that we ought to seek an alternative. I offer a charitable interpretation of the doctrine that necessity and strict universality are sufficient conditions of a priority, commenting briefly on comparable necessary conditions.     

Knowledge and modality

Kripke claims that there are necessary a posteriori truths and contingent a priori truths. These claims challenge the traditional Kantian view that

1. (K)
   All knowledge of necessary truths is a priori and all a priori knowledge is of necessary truths.
    

Kripke’s claims continue to be resisted, which indicates that the Kantian view remains attractive. My goal is to identify the most plausible principles linking the epistemic and the modal. My strategy for identifying the principles is to investigate two related questions. Are there compelling general supporting arguments for (K)? Are there decisive counterexamples to (K)? My investigation uncovers two intuitively plausible principles that are not open to decisive counterexamples but which enjoy no compelling independent support.

     

Necessity and Apriority

The classical view of the relationship between necessity and apriority, defended by Leibniz and Kant, is that all necessary truths are known a priori. The classical view is now almost universally rejected, ever since Saul Kripke and Hilary Putnam discovered that there are necessary truths that are known only a posteriori. However, in recent years a new debate has emerged over the epistemology of these necessary a posteriori truths. According to one view – call it the neo-classical view – knowledge of a necessary truth always depends on at least one item of a priori knowledge. According to the rival view – call it the neoempiricist view – our knowledge of necessity is sometimes broadly empirical. In this paper I present and defend an argument against the neo-empiricist view. I argue that knowledge of the necessity of a necessary truth could not be broadly empirical.     

BEALER ON THE AUTONOMY OF PHILOSOPHICAL AND SCIENTIFIC KNOWLEDGE

Abstract: In a series of influential articles, George Bealer argues for the autonomy of philosophical knowledge on the basis that philosophically known truths must be necessary truths. The main point of his argument is that the truths investigated by the sciences are contingent truths to be discovered a posteriori by observation, while the truths of philosophy are necessary truths to be discovered a priori by intuition. The project of assimilating philosophy to the sciences is supposed to be rendered illegitimate by the more or less sharp distinction in these characteristic methods and its modal basis. In this article Bealer's particular way of drawing the distinction between philosophy and science is challenged in a novel manner, and thereby philosophical naturalism is further defended.     

NECESSITY, APRIORITY, AND LOGICAL STRUCTURE

Logical structure may explain the necessity and a priori knowability of such truths as that if A is red then A is either red or green. But this explanation cannot be extended to sentences that, while necessary and knowable a priori, do not wear the appropriate logical structure on their sleeves – sentences like 'if A is a point and A is red, then A is not green,' or 'if A is a sphere, then A is not a cube.' The real origin of these sentences' necessity and a priori knowability is a relationship between the meanings of their component atomic sentences – a relationship which cannot be systematically reduced to logical structure by translating those atomic sentences into any kind of 'ideal' language. Moreover, this kind of relationship is one to which any atomic sentences are susceptible if they have a classifying, or comparison-implying, content. Arguably, then, all atomic sentences are capable of being related to others in ways that are necessary and knowable a priori.     

On Considering a Possible World as Actual: Thomas Baldwin

Two-dimensional possible world semantic theory suggests that Kripke's examples of the necessary a posteriori and contingent a priori should be handled by interpreting names as implicitly indexical. Like Stalnaker, I reject this account of names and accept that Kripke's examples have to be accommodated within a metasemantic theory. But whereas Stalnaker maintains that a metasemantic approach undermines the conception of a priori truth, I argue that it offers the opportunity to develop a conception of the a priori aspect of stipulations, conceived as linguistic performances. The resulting position accommodates Kripke's examples in a way which is both intrinsically plausible and fits with Kripke's actual discussion of them.     

Contingent A Priori Knowledge

I argue that you can have a priori knowledge of propositions that neither are nor appear necessarily true. You can know a priori contingent propositions that you recognize as such. This overturns a standard view in contemporary epistemology and the traditional view of the a priori, which restrict a priori knowledge to necessary truths, or at least to truths that appear necessary.     

Kripke's sole route to the necessary a posteriori

In ‘Kripke on epistemic and metaphysical possibility: two routes to the necessary a posteriori’, Scott Soames identifies two arguments for the existence of necessary a posteriori truths in Naming and Necessity (NN). He argues that Kripke's second argument relies on either of two principles, each of which leads to contradiction. He also claims that it has led to ‘two-dimensionalist’ approaches to the necessary a posteriori which are fundamentally at odds with the insights about meaning and modality expressed in NN. I argue that the alleged second argument is not in NN. I identify the mistakes that lead to Soames' misinterpretation.     

Proper Names and the Necessity of Identity Statements

An identity statement flanked on both sides with proper names is necessarily true, Saul Kripke thinks, if it's true at all. Thus, contrary to the received view – or at least what was, prior to Kripke, the received view – a statement like(A) Hesperus is Phosphorusis necessarily true if, as certainly seems to the the case, it's true at all. The received view is that (A) is true but only contingently true, while(B) Hesperus is Hesperuswhich is also true, of course, is necesarily true. Epistemologically, however, both the tradition and Kripke have it that (A) is a posteriori and (B) a priori.There are tensions in Kripke's views concerning (A), though, and ultimately in the views of anyone who holds that (A) is necessary. In this paper I draw attention to some of them and advance an argument for thinking that (A) is contingent.     

Units of measurement and natural kinds: Some kripkean considerations

Kripke has argued that definitions of units of measurements provide examples of statements that are both contingent and a priori. In this paper I argue that definitions of units of measurement are intended to be stipulations of what Kripke calls theoretical identities: a stipulation that two terms will have the same rigid designation. Hence such a definition is both a priori and necessary. The necessity arises because such definitions appeal to natural kind properties only, which on Kripke's account are necessary.Earlier versions of this paper have been presented at the philosophy departments of the universities of Berlin and Salzburg and at the 1986 Eastern Division Meeting of the American Philosophical Association. I have benefited from points raised in discussions after these presentations, particularly from comments by E. Lashchyk read at the APA-meeting.     

奎因对模态逻辑的批评

奎因对模态逻辑的批评包括：(i)因为模态语境是指称不透明的,所以对其量化纳入没有意义;(ii)一些关于必然真理的经验知识与关于必然性的语言学理论不相容;(iii)模态语境中的量化纳入承诺了“亚里士多德式的本质主义”。丘奇,克里普克和福雷斯达尔对奎因提出了批评。他们提出,模态构造应该是外延上不透明但指称上透明的。奎因式诉诸于模态环境指称不透明的批评,在不采用单称词项的模态逻辑中不成立。他对本质主义的批评引入了一种必然性,但这种必然性没有办法用语言陈述词项进行解释。通过对语言中名称使用的讨论,我们可以看出,有关包含名称的同一性陈述的真值的经验知识,和卡苏洛称之为“一般模态地位”的先验知识是相容的。既然奎因论证了真同一性陈述的必然真是逻辑真,而且所有逻辑真都遵循戴维森式的意义理论（另文讨论）,那么我们可以给出一个关于包含名称的同一性的真陈述的模态地位的先验知识的语言学理论。     

Thought-experiment intuitions and truth in fiction

What sorts of things are the intuitions generated via thought experiment? Timothy Williamson has responded to naturalistic skeptics by arguing that thought-experiment intuitions are judgments of ordinary counterfactuals. On this view, the intuition is naturalistically innocuous, but it has a contingent content and could be known at best a posteriori. We suggest an alternative to Williamson’s account, according to which we apprehend thought-experiment intuitions through our grasp on truth in fiction. On our view, intuitions like the Gettier intuition are necessarily true and knowable a priori. Our view, like Williamson’s, avoids naturalistic skepticism.     

Fairness heuristic theory is an empirical framework: a reply to Arnadóttir

In this article on fairness heuristic theory, we point out some important flaws in Arnadóttir's (2002) claim that fairness heuristic theory is "not empirical," by which Arnadóttir meant that theory's predictions are knowable a priori, and are not contingent upon circumstances. To this end, we demonstrate that empirically testing effects predicted by fairness heuristic theory was and is important because this showed that the theory's propositions are not necessarily knowable a priori and are contingent upon circumstances. This implies that, according to Arnadóttir's definition, fairness heuristic theory clearly is an empirical framework. It would have been helpful if Arnadóttir had studied the fairness literature more thoroughly (as this would have easily revealed fairness heuristic theory to be not knowable a priori and to be contingent upon circumstances) and also if she had pointed out which of our studies fail to follow her line of reasoning. Our reply was written not as an attempt to defend fairness heuristic theory as we applaud, indeed are honored by, attempts to scrutinize our work in progress. Our only aim here was to point at some important flaws in the Arnadóttir article, because we think these will hamper rather than advance the science of psychology of justice.     

Deflationism about the necessary a posteriori and Twin Earth

Some necessary truths are a posteriori. That’s widely agreed and is presumed here. Their existence might appear to show that discoveries about how things are in fact—about how things actually are—can lead to discoveries about all the ways things might be, about the nature of logical space. I detail one way of resisting this conclusion for a number of examples, and the implications of Twin Earth for the issue. Central is the notion of a Cambridge discovery.

     

Unexpected a posteriori necessary laws of nature

In this paper I argue that it is not a priori that all the laws of nature are contingent. I assume that the fundamental laws are contingent and show that some non-trivial, a posteriori, non-basic laws may nonetheless be necessary in the sense of having no counterinstances in any possible world. I consider a law L_S (such as ‘salt dissolves in water’) that concerns a substance S. Kripke's arguments concerning constitution show that the existence of S requires that a certain deeper level law or variants thereof hold. At the same time, that law and its variants may each entail the truth of L_S. Thus the existence of S entails L_S. Consequently there is no world in which S exists and fails to obey L_S. I consider the conditions concerning the fundamental laws that would make this phenomenon ubiquitous. I conclude with some consequences for metaphysics.     

Mental Manipulations and the Problem of Causal Exclusion

Leibniz has long faced a challenge about the coherence of the distinction between necessary and contingent truths in his philosophy. In this paper, I propose and examine a new way to save genuine contingency within a Leibnizian framework. I conclude that it succeeds in formally solving the problem, but at unbearable cost. I present Leibniz's challenge by considering God's choice of the best possible world (Sect. 2). God necessarily exists and necessarily chooses to actualize the best possible world. The actual world therefore could not be different, for if it were different it would be a distinct and inferior world and hence would not be created. In Section 3, I defend Leibniz from this challenge. I argue that, while it is necessary for God to choose to create the best possible world, it is not necessary for any world to be the best possible. This is because the criterion for judging perfection can itself be contingent. Different criteria will judge different worlds as the best. Thus it is necessary for God to create the best, but not necessary which is the best. Distinguishing between possible worlds in Leibniz's sense and in the modern sense allows a fuller exposition of this position. There are worries that can arise with the claim that the criterion of perfection is contingent. I consider two of the most pressing (Sect. 4). The first argues that the criterion is in God's understanding and hence is necessary; the second alleges that a contingent criterion of perfection violates Leibniz's cherished Principle of Sufficient Reason. These worries are well grounded, and examining them reveals a deep incompatibility between this solution and Leibniz's metaphysical views. I conclude that there is a real solution available, but that it is unacceptable to Leibniz or a Leibnizian. The search for a genuine solution that is genuinely Leibnizian goes on.     

Knowability and bivalence: intuitionistic solutions to the Paradox of Knowability

In this paper, I focus on some intuitionistic solutions to the Paradox of Knowability. I first consider the relatively little discussed idea that, on an intuitionistic interpretation of the conditional, there is no paradox to start with. I show that this proposal only works if proofs are thought of as tokens, and suggest that anti-realists themselves have good reasons for thinking of proofs as types. In then turn to more standard intuitionistic treatments, as proposed by Timothy Williamson and, most recently, Michael Dummett. Intuitionists can either point out the intuitionistc invalidity of the inference from the claim that all truths are knowable to the insane conclusion that all truths are known, or they can outright demur from asserting the existence of forever-unknown truths, perhaps questioning—as Dummett now suggests—the applicability of the Principle of Bivalence to a certain class of empirical statements. I argue that if intuitionists reject strict finitism—the view that all truths are knowable by beings just like us—the prospects for either proposal look bleak.     

INTER-WORLD PROBABILITY AND THE PROBLEM OF INDUCTION

Abstract:  Laurence BonJour has recently proposed a novel and interesting approach to the problem of induction. He grants that it is contingent, and so not a priori , that our patterns of inductive inference are reliable. Nevertheless, he claims, it is necessary and a priori that those patterns are highly likely to be reliable, and that is enough to ground an a priori justification induction. This paper examines an important defect in BonJour's proposal. Once we make sense of the claim that inductive inference is "necessarily highly likely" to be reliable, we find that it is not knowable a priori after all.     

The necessary a posteriori: A response to Tichý

Conclusion Some of Tichý's conclusions rest on an assumption about substitutivity which Kripke would not accept. If we grant the assumption, then Tichý successfully shows that we can discover true identity statements involving names a priori, but not that we can discover a priori what properties things have essentially. Many of Tichý's arguments require an implausible rejection of the possibility of indirect belief as described in Section III. 25Are there necessary a posteriori propositions? I have argued that we certainly can discover necessary propositions a posteriori, but have left it an open question whether there are necessary propositions which we can only discover a posteriori.What effect do the considerations here presented have on the positivist doctrine that the a priori and the necessary coincide? My explanation of how we discover necessary propositions a posteriori involves our believing them indirectly, in virtue of believing contingent propositions. I would argue that Kripke's examples of the contingent a priori involve, similarly, our believing the contingent propositions in directly, in virtue of believing necessary propositions.This suggests that a reformulation of the positivist thesis along something like the following lines may well be correct. Let us say that someone directly believes a proposition just in case he could not fail to believe it without being in a different cognitive state. Then perhaps one can directly believe a proposition on the basis of a priori evidence only if it is necessary, and can directly believe a proposition on the basis of a posteriori evidence only if it is contingent.     

Necessities of Origin and Constitution

The once deeply held conviction that all necessary truths are known a priori is now widely, although by no means universally agreed to have been subjected to penetrating, if not devastating criticism. Scott Soames, for example, on behalf of Saul Kripke, and indirectly of Hilary Putnam, argues that in respect of natural kinds, the introduction of basic essentialist assumptions grounded in our pre-theoretical habits of thinking and speaking – for example, that atomic or molecular structure provides the underlying essence of a substance – allows a sentence like "water = H₂0," in which the identity sign is flanked by rigid designators to express a metaphysically necessary truth. Yet doubts and puzzlement remain over the status of a posteriori necessities, including those relating to an individual's origin. This paper considers some prominent criticisms that have been made of the Kripke–Putnam approach by A. J. Ayer and Frank Ebersole among others and reveals in what respects they are valid, where they are misplaced, and, perhaps more importantly, why the most valuable aspect of this approach can be seen to reflect aspects of our scientific procedures that do indeed point towards an application for a distinction that roughly mirrors that between epistemic and metaphysical possibility, yet one that is grounded instead in the nature of our actual practices.