Theoria: A Swedish Journal of Philosophy, Vol. 75, No. 2, pp. 344–357, 2009. The original publication is available at the journal's website (or e-mail me for a pdf-offprint).

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.

The Australasian Journal of Logic, Vol. 7, pp. 32-47, 2009. The original publication is available at the journal's website.

The goals of this paper are two-fold: I wish to clarify the Aristotelian conception of the law of non-contradiction as a metaphysical rather than a semantic or logical principle, and to defend the truth of the principle in this sense. First I will explain what it in fact means that the law of non-contradiction is a metaphysical principle. The core idea is that the law of non-contradiction is a general principle derived from how things are in the world. For example, there are certain constraints as to what kind of properties an object can have, and especially: some of these properties are mutually exclusive. Given this characterisation, I will advance to examine what kind of challenges the law of noncontradiction faces—the main opponent here is Graham Priest. I will consider these challenges and conclude that they do not threaten the truth of the law of noncontradiction understood as a metaphysical principle.

Philosophia, Vol. 37, No. 2, pp. 335-40, 2009. The original publication is available at www.springerlink.com.

In this paper I offer a counterexample to the so called vagueness argument against restricted composition. This will be done in the lines of a recent suggestion by Trenton Merricks, namely by challenging the claim that there cannot be a sharp cut-off point in a composition sequence. It will be suggested that causal powers which emerge when composition occurs can serve as an indicator of such sharp cut-off points. The main example will be the case of a heap. It seems that heaps might provide a very plausible counterexample to the vagueness argument if we accept the idea that four grains of sand is the least number required to compose a heap—the case has been supported by W. D. Hart. My purpose here is not to put forward a new theory of composition, I only wish to refute the vagueness argument and point out that we should be wary of arguments of its form.

Metaphysica, Vol. 9, No. 2, pp. 57-68, 2008. The original publication is available at www.springerlink.com.

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 actualworld 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.

In Dale Jacquette (Ed.) Cannabis and Philosophy: What Were We Just Talking About? (Oxford: Wiley-Blackwell), pp. 149-161, 2010. The volume is available here.

This paper is a survey of the positive and negative aspects of cannabis use from the point of view of the individual on one hand and from the point of view of the society on the other hand. Health, social, and political motives are all discussed, and the best method of harm reduction is analysed. The upshot is that zero tolerance policy is obsolete, and that most individuals would be better off using cannabis rather than other drugs.

In Michal Peliš (Ed.) The Logica Yearbook 2007 (Prague: Filosofia), pp. 225-235, 2008.

The purpose of this paper is to examine the status of logic from a metaphysical point of view – what is logic grounded in and what is its relationship with metaphysics. There are three general lines that we can take. 1) Logic and metaphysics are not continuous, neither discipline has no bearing on the other one. This seems to be a rather popular approach, at least implicitly, as philosophers often skip the question altogether and go about their business, be it logic or metaphysics. However, it is not a particularly plausible view and it is very hard to maintain consistently, as we will see. 2) Logic is prior to metaphysics and has metaphysical implications. The extreme example of this kind of approach is the Dummettian one, according to which metaphysical questions are reducible to the question of which logic to adopt. 3) Metaphysics is prior to logic, and your logic should be compatible with your metaphysics. This approach suggests an answer to the question of what logic is grounded in, namely, metaphysics. Here I will defend the third option.

In Patricia Hanna (Ed.), An Anthology of Philosophical Studies (Athens: ATINER), pp. 53-63, 2008.

In this paper I examine what exactly is ‘Aristotelian metaphysics’. My inquiry into Aristotelian metaphysics should not be understood to be so much concerned with the details of Aristotle's metaphysics. I am are rather concerned with his methodology of metaphysics, although a lot of the details of his metaphysics survive in contemporary discussion as well.
This warrants an investigation into the methodological aspects of Aristotle's metaphysics. The key works that we will be looking at are his Physics, Metaphysics, Categories and De Interpretatione. Perhaps the most crucial features of the Aristotelian method of philosophising are the relationship between science and metaphysics, and his defence of the principle of non-contradiction (PNC). For Aristotle, natural science is the second philosophy, but this is so only because there is something more fundamental in the world, something that natural science – a science of movement – cannot study. Furthermore, Aristotle demonstrates that metaphysics enters the picture at a fundamental level, as he argues that PNC is a metaphysical rather than a logical principle.
The upshot of all this is that the Aristotelian method and his metaphysics are not threatened by modern science, quite the opposite. Moreover, we have in our hands a methodology which is very rigorous indeed and worthwhile for any metaphysician to have a closer look at.

Deflationism about modality suggests that modal statements can be analysed strictly in terms of linguistic content, and that apriority reduces to analyticity. Scott Soames is explicitly opposed to this trend and I sympathise with this approach. However, a detailed study of Soames’ own account reveals that it has striking similarities with the deflationary account. In this paper I will compare Soames’ account of a posteriori necessities with the deflationary one, specifically Alan Sidelle’s account, and suggest that Soames’ account is vulnerable to the deflatonist’s criticism. I will then sketch a more fine-grained, essentialist account using the case of water and H2O as a case study. With reference to some recent work in the philosophy of chemistry, I will argue that both the deflationary account and Soames’ account fail to fully explicate the metaphysical status of modal statements.

This paper concerns the puzzle about the existence of a fundamental level of reality. While I will argue that we have some good reasons to think that there is a fundamental level, the most important contribution of the paper is perhaps methodological: the ‘levels’ metaphor, our means to inquire into the existence of a fundamental level, and our means to study the nature of this level will all be discussed. Specifically, we will consider the role of ontological dependence regarding the levels of reality and consider whether an a priori argument for the existence of a fundamental level can be produced. Finally, the role of current physics in our search for a fundamental level will be analysed, and we will see that a study of fundamental physical constants, such as the fine structure constant, and of certain physical principles, such as the Pauli Exclusion Principle, will be of particular interest. Input from emerging work in quantum mechanics will also be considered, and we will see that so called loop quantum gravity may offer some support for the existence of a fundamental level.

How many different kinds of modality – different realms of possible worlds – are there? Philosophers commonly talk at least about metaphysical, conceptual, epistemic, logical, physical, mathematical, biological, technological, normative and natural modality. It is not always clear how these different types of modality are related, or whether some of them are more fundamental than others. The relationships between metaphysical, conceptual and logical necessity and possibility are particularly interesting. This paper is a survey of our options in this regard. We can distinguish four approaches which are currently widely discussed: the Kripkean approach, the conservative approach, the conceptualist approach, and the essentialist approach. The differences between these approaches are best described by comparing their takes on the distinction between metaphysical and conceptual modality. The Kripkean approach holds that this distinction is genuine and that we are dealing with two different kinds of modality. The conservative approach, which is familiar for instance from Bob Hale’s work, challenges the role of metaphysical modality and suggests that logical necessity is the most fundamental type of modality, it is absolute. The conceptualist approach, most forcefully argued for by Frank Jackson and David Chalmers, also questions the distinction and suggests that metaphysical modality can be fully accounted for in terms of conceptual modality. Finally, the essentialist approach, defended especially by Kit Fine, suggests that conceptual and logical modality can be seen as species of metaphysical modality. I will also consider an alternative approach based on the essentialist approach, which takes metaphysical modality to be absolute in Hale’s sense.

There are (at least) two competing interpretations of the notion of logical truth: a linguistic and a metaphysical. In this paper I will propose a metaphysical interpretation of the notion and examine what kind of implications this interpretation has for logical pluralism, the normativity of logic, and the study of logic more generally.

What is our epistemic access to metaphysical modality? Timothy Williamson claims that the epistemology of counterfactuals will provide the answer. This paper challenges Williamson’s account and argues that certain elements of the epistemology of counterfactuals that he sketches, namely so called background knowledge and constitutive facts, are already saturated with modal content which his account fails to explain. Furthermore, Williamson’s account is unable to accommodate the distinction between conceivable yet metaphysically impossible scenarios, and conceivable and metaphysically possible scenarios. These problems, it will be suggested, cannot be overcome with a counterfactual account of the epistemology of modality.

Euclidean geometry is now commonly considered to have been justified a priori for Kant, but not for us. This entails that a priori justification is empirically defeasible. In this paper I will re-evaluate the status of alternative geometries such as Euclidean geometry and suggest that they are still justified a priori. What we need to change is our conception of apriority. The suggestion that will be offered is that we should move away from the epistemic discussion concerning a priori justification, as this leaves a more fundamental problem unanswered: the relationship between the apriority and the truth of a proposition. By distinguishing between pure geometry which can be understood as being true in a model, and applied geometry which is true in the world, we can redefine apriority in such a way that empirical indefeasibility can be maintained.

This paper addresses three conventionalist criticisms against realism. They are all based on the idea that the manner in which we structure, divide and carve up the world is not based on any natural, genuine boundaries in the world. The first criticism that will be examined concerns the idea that there are no natural boundaries in the world, the second one focuses on the basis of our classificatory schemes, which the conventionalist claims to be psychological, and the third considers the significance of our particular features in carving up the world, such as physical size and perceptual capabilities. The purpose of the paper is to demonstrate that none of these objections succeed in undermining realism.

Recent literature suggests that truthmaking is not compatible just with realism, but also with pragmatism and idealism, and thus does not help in defending realism in general. I take this point and show that in fact the wider applicability of the truthmaker principle only strengthens the realist's case, for all that is needed is a plausible way to account for our realist intuitions concerning truth. It will be demonstrated that to motivate truthmaking, we only need a weakened understanding of the truthmaker principle. All this is grist to the realist's mill, as one influential challenge for realism, in the lines of Hilary Putnam, Michael Dummett and Nelson Goodman, is its inability to put forward a plausible theory of truth. This objection can now be easily refuted: the truthmaker principle, widely conceived, is just the missing piece – its applicability beyond realist ontologies only increases its plausibility.

The combination of two-dimensional modal semantics and conceivability purports to be very powerful: it upholds modal rationalism, explains a posteriori necessity, and even accounts for metaphysical impossibilities—all this while committing to only one modal space, conceptual modality. In this paper I will examine whether two-dimensional modal semantics and conceivability can produce a complete account of modal epistemology and argue that they cannot. We will see that the framework is not able to account for metaphysical modality or to deal with metaphysically substantial, essentialist statements because it is unable to distinguish between trivial and substantial a priori truths.