Online research in philosophy

Two sentences express the same proposition if they are synonymous; they express the same statement if they attribute the same properties to the same objects at the same time (however objects and times are picked out). Neither propositions nor statements are necessary a posteriori. Suggested examples of the necessary a posteriori, such as "Hesperus is Phosphorus", or "water is H2O", only appear to be such because of a confusion between proposition and statement.

I present and defend a unified, non-reductive analysis of the a priori and a posteriori. It is a mistake to remove all epistemic conditions from the analysis of the a priori (as, for example, Alvin Goldman has recently suggested doing). We can keep epistemic conditions (like unrevisability) in the analysis as long as we insist that a priori and a posteriori justification admit of degrees. I recommend making the degree to which a belief’s justification is a priori or a posteriori solely dependent on the revisability relations that obtain among the faculties that deliver the belief and all other faculties.

The terms "a priori" and "a posteriori" refer primarily to how or on what basis a proposition might be known. A proposition is knowable a priori if it is knowable independently of experience. A proposition is knowable a posteriori if it is knowable on the basis of experience. The a priori/a posteriori distinction is epistemological and should not be confused with the metaphysical distinction between the necessary and the contingent or the semantical or logical distinction between the analytic and the synthetic. Two aspects of the a priori/a posteriori distinction require clarification: the conception of experience on which the distinction turns; and the sense in which a priori knowledge is independent of such experience. The latter gives rise to important questions regarding the positive basis of a priori knowledge.

This paper challenges the Kripkean interpretation of a posteriori necessities. It will be demonstrated, by an analysis of classic examples, that the modal content of supposed a posteriori necessities is more complicated than the Kripkean line suggests. We will see that further research is needed concerning the a priori principles underlying all a posteriori necessities. In the course of this analysis it will emerge that the modal content of a posteriori necessities can be best described in terms of a Finean conception of modality – by giving essences priority over modality. The upshot of this is that we might be able to establish the necessity of certain supposed a posteriori necessities by a priori means.

Chalmers argues that zombies are possible and that therefore consciousness does not supervene on physical facts, which shows the falsity of materialism. The crucial step in this argument – that zombies are possible – follows from their conceivability and hence depends on assuming that conceivability implies possibility. But while Chalmers’s defense of this assumption – call it the conceivability principle – is the key part of his argument, it has not been well understood. As I see it, Chalmers’s defense of the conceivability principle comes in his response to the so-called objection from a posteriori necessity. The defense aims at showing that there is no gap between conceivability and possibility since no such gap can be generated by necessary a posteriori truths. I will argue that while Chalmers is right to the extent that there is no gap between conceivability and possibility within the standard Kripkean model of a posteriori necessity, his general conclusion is not justified. This is because the conceivability principle might be inconsistent with a posteriori necessity understood in some non-Kripkean way and Chalmers has not shown that no such alternative understanding of a posteriori necessity is available.

The distinction between a priori and a posteriori knowledge has been the subject of an enormous amount of discussion, but the literature is biased against recognizing the intimate relationship between these forms of knowledge. For instance, it seems to be almost impossible to find a sample of pure a priori or a posteriori knowledge. In this paper, it will be suggested that distinguishing between a priori and a posteriori is more problematic than is often suggested, and that a priori and a posteriori resources are in fact used in parallel. We will define this relationship between a priori and a posteriori knowledge as the bootstrapping relationship. As we will see, this relationship gives us reasons to seek for an altogether novel definition of a priori and a posteriori knowledge. Specifically, we will have to analyse the relationship between a priori knowledge and a priori reasoning , and it will be suggested that the latter serves as a more promising starting point for the analysis of aprioricity. We will also analyse a number of examples from the natural sciences and consider the role of a priori reasoning in these examples. The focus of this paper is the analysis of the concepts of a priori and a posteriori knowledge rather than the epistemic domain of a posteriori and a priori justification.

Pavel Tichy presents an interpretation of Anselm’s Proslogion III argument. Tichy presents an interpretation of this argument and raises doubts about one of the premises. The authors contend that Tichy’s interpretation of Anselm is wrong. The argument Tichy comes to raise doubts about is not Anselm’s.

We think that Kripke’s arguments that there are contingent a priori truths and that there are necessary a posteriori truths about named and essentially described entities fail. They fail for the reasons that there are ambiguities in each of the three eases. In the first ease, what is known apriori is not what is contingent. In the latter two cases, what is necessary or essential is not what is known a posteriori.