Online research in philosophy

In what follows, I argue that Hume works with a notion of the a priori that, though unfamiliar today, was standard in the seventeenth and eighteenth centuries. On this notion of the a priori, to know (consider, prove) something a priori is to know (consider, prove) it from the grounds that make it true. I will refer to this as the "from-grounds" notion of the a priori, and to the now-familiar and dominant notion—on which to know something a priori is to know it with a justification that is independent of experience—as the "non-empirical" notion.Hume holds, as a substantive thesis, that one knows something a priori, where 'a priori' is understood in the from-grounds sense, only if one knows it independently of ..

These days 'evolution' is usually defined as any change in the relative frequencies of genes in a population over time. This definition and some obvious alternatives are examined and rejected. The criticism of these definitions points out the need for a more holistic analysis of genotypes. I attempt such analysis by introducing measures of similarity of whole genotypes and then by grouping genotypes into similarity classes. Three sorts of measures of similarity are examined: a measure of structural similarity, a measure of functional similarity and one of relational or historical similarity. The functional approach is shown to be superior and a definition of 'evolution' is suggested.

The book sets out to analyse the notion of a priori justification and of a priori knowledge.

In this paper, I investigate the nature of a priori biological laws in connection with the idea that laws must be empirical. I argue that the epistemic functions of a priori biological laws in biology are the same as those of empirical laws in physics. Thus, the requirement that laws be empirical is idle in connection with how laws operate in science. This result presents a choice between sticking with an unmotivated philosophical requirement and taking the functional equivalence of laws seriously and modifying our philosophical account. I favor the latter.

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.

A thumbnail sketch of the philosophical thinking about the a priori would surely include that it has been dominated by two major approaches: the Kantian absolute conception of it and the Millian-Quinean absolute rejection of it (section 2). Yet, one can find in the literature claims about the existence of a ›functional a priori‹, a ›relative a priori‹, a ›relativised a priori‹ and suchlike. They are all meant to carve a space between the two extremes. An important thought behind the search for a middle ground is that the supposed coincidence between the constitutive and the unrevisable is wrong. The entitlement to accept a principle as being constitutive of experience prior to any empirical justification of it is compatible with an entitlement to revise or abandon such a principle on empirical grounds. If a priori principles are meant to be independent of experience, how should this claim of independence be understood so that room is left for the possibility that a principle is both independent of experience and revisable on empirical grounds (section 3)? A straightforward and natural way to approach this issue is to think of constitutive principles along the lines of Poincaréan conventions, which can be seen as delineating a new sense of the a priori – the conventional a priori principles. These are substantive principles that are constitutive of theoretical frameworks – in the sense that they define (or constitute) the object of knowledge – without being either synthetic a priori or empirical generalisations. Still, their negation is conceivable and they are revisable on empirical grounds (section 4).

What is the fundamental insight behind truth-functionality ? When is a logic interpretable by way of a truth-functional semantics? To address such questions in a satisfactory way, a formal definition of truth-functionality from the point of view of abstract logics is clearly called for. As a matter of fact, such a definition has been available at least since the 70s, though to this day it still remains not very widely well-known. A clear distinction can be drawn between logics characterizable through: (1) genuinely finite-valued truth-tabular semantics; (2) no finite-valued but only an infinite-valued truthtabular semantics; (3) no truth-tabular semantics at all. Any of those logics, however, can in principle be characterized through non-truth-functional valuation semantics, at least as soon as their associated consequence relations respect the usual tarskian postulates. So, paradoxical as that might seem at first, it turns out that truth-functional logics may be adequately characterized by non-truth-functional semantics . Now, what feature of a given logic would guarantee it to dwell in class (1) or in class (2), irrespective of its circumstantial semantic characterization?

In this paper I will offer a novel understanding of a priori knowledge. My claim is that the sharp distinction that is usually made between a priori and a posteriori knowledge is groundless. It will be argued that a plausible understanding of a priori and a posteriori knowledge has to acknowledge that they are in a constant bootstrapping relationship. It is also crucial that we distinguish between a priori propositions that hold in the actual world and merely possible, non-actual a priori propositions, as we will see when considering cases like Euclidean geometry. Furthermore, contrary to what Kripke seems to suggest, a priori knowledge is intimately connected with metaphysical modality, indeed, grounded in it. The task of a priori reasoning, according to this account, is to delimit the space of metaphysically possible worlds in order for us to be able to determine what is actual.

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.