This paper is inspired by and develops on E. J. Lowe’s work, who writes in his book The Possibility of Metaphysics that ‘metaphysical possibility is an inescapable determinant of actuality’ (1998: 9). Metaphysics deals with possibilities – metaphysical possibilities – but is not able to determine what is actual without the help of empirical research. Accordingly, a delimitation of the space of possibilities is required. The resulting – controversial – picture is that we generally need to know whether something is (...) possible before we can know whether it is actual. In order to appreciate this picture, we need to understand Lowe’s slogan: ‘essence precedes existence’ (Lowe 2008: 40). This slogan has both an ontological and an epistemic reading. The ontological reading is related to the now familiar idea that essence grounds modality, as popularised by Kit Fine. The epistemic reading suggests that we can know the essence of some entity before we know whether or not that entity exists. However, this idea is often met with puzzlement and Lowe himself sadly passed away before he had a chance to clarify this framework. I will present the framework as I understand it, develop it on my own terms, and put forward a qualified defence of it. I will also illustrate how the framework can be put to use with a case study concerning the discovery of transuranic elements. (shrink)

A dialetheia is a sentence, A, such that both it and its negation, ¬A, are true (we shall talk of sentences throughout this entry; but one could run the definition in terms of propositions, statements, or whatever one takes as her favourite truth-bearer: this would make little difference in the context). Assuming the fairly uncontroversial view that falsity just is the truth of negation, it can equally be claimed that a dialetheia is a sentence which is both true and false.

Logical realism is a view about the metaphysical status of logic. Common to most if not all the views captured by the label ‘logical realism’ is that logical facts are mind- and language-independent. But that does not tell us anything about the nature of logical facts or about our epistemic access to them. The goal of this paper is to outline and systematize the different ways that logical realism could be entertained and to examine some of the challenges that these (...) views face. It will be suggested that logical realism is best understood as a metaphysical view about the logical structure of the world, but this raises an important question: does logical realism collapse into standard metaphysical realism? It will be argued that this result can be accommodated, even if it cannot be altogether avoided. (shrink)

Abstract‘Logical Realism’ is taken to mean many different things. I argue that if reality has a privileged structure, then a view I call metaphysical logical realism is true. The view says that, first, there is ‘One True Logic’; second, that the One True Logic is made true by the mind‐and‐language‐independent world; and third, that the mind‐and‐language‐independent world makes it the case that the One True Logic is better than any other logic at capturing the structure of reality. Along the way, (...) I discuss a few alternatives, and clarify two distinct kinds of metaphysical logical realism. (shrink)

I provide a comprehensive metaphysics of causation based on the idea that fundamentally things are governed by the laws of physics, and that derivatively difference-making can be assessed in terms of what fundamental laws of physics imply for hypothesized events. Highlights include a general philosophical methodology, the fundamental/derivative distinction, and my mature account of causal asymmetry.

Dialetheism is the view that some contradictions are true. Resorting to either metaphysical dialetheism or semantic dialetheism may seem like an appropriate resolve to certain theological contradictions. At least for those who concede to theological contradictions, and take dialetheism seriously. However, I demonstrate that neither of these types of dialetheism would serve to be amenable in resolving an Islamic theological contradiction. This is a theological contradiction that I refer to as ‘the paradox of an unknowable and ineffable God’. As a (...) result of this, I propose an alternative type of dialetheism which aims to resolve the paradox of an unknowable and ineffable God. I call this type of dialetheism, ‘mystical dialetheism’. (shrink)

The starting point of this paper concerns the apparent difference between what we might call absolute truth and truth in a model, following Donald Davidson. The notion of absolute truth is the one familiar from Tarski’s T-schema: ‘Snow is white’ is true if and only if snow is white. Instead of being a property of sentences as absolute truth appears to be, truth in a model, that is relative truth, is evaluated in terms of the relation between sentences and models. (...) I wish to examine the apparent dual nature of logical truth (without dwelling on Davidson), and suggest that we are dealing with a distinction between a metaphysical and a linguistic interpretation of truth. I take my cue from John Etchemendy, who suggests that absolute truth could be considered as being equivalent to truth in the ‘right model’, i.e., the model that corresponds with the world. However, the notion of ‘model’ is not entirely appropriate here as it is closely associated with relative truth. Instead, I propose that the metaphysical interpretation of truth may be illustrated in modal terms, by metaphysical modality in particular. One of the tasks that I will undertake in this paper is to develop this modal interpretation, partly building on my previous work on the metaphysical interpretation of the law of non-contradiction (Tahko 2009). After an explication of the metaphysical interpretation of logical truth, a brief study of how this interpretation connects with some recent important themes in philosophical logic follows. In particular, I discuss logical pluralism and propose an understanding of pluralism from the point of view of the metaphysical interpretation. (shrink)

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. (shrink)

A dialetheia is a sentence, A, such that both it and its negation, A, are true (we shall talk of sentences throughout this entry; but one could run the definition in terms of propositions, statements, or whatever one takes as her favourite truth bearer: this would make little difference in the context). Assuming the fairly uncontroversial view that falsity just is the truth of negation, it can equally be claimed that a dialetheia is a sentence which is both true and (...) false. (shrink)

Can the neo-Aristotelian uphold a pluralist substance ontology while taking seriously the recent arguments in favour of monism based on quantum holism and other arguments from quantum mechanics? In this article, Jonathan Schaffer’s priority monism will be the main target. It will be argued that the case from quantum mechanics in favour of priority monism does face some challenges. Moreover, if the neo-Aristotelian is willing to consider alternative ways to understand ‘substance’, there may yet be hope for a pluralist substance (...) ontology. A speculative case for such an ontology will be constructed based on primitive incompatibility. (shrink)

I introduce a novel and quite intuitive interpretation of the ternary relation that figures in the relational semantics of many relevance logics. Conceptually, my interpretation makes use only of incompatibility and parthood relations, defined over a set of states. In this way, the proposed interpretation—of the ternary relation and the conditional—extends Dunn’s and Restall’s works on negation and the Routley star operator. Therefore, the interpretation is unified, and hence not only intuitive but also parsimonious. Additionally, the interpretation provides us with (...) a cogent argument to the effect that a ternary relation is indispensable, and we cannot merely do with a binary relation. (shrink)

The anti-exceptionalist debate brought into play the problem of what are the relevant data for logical theories and how such data affects the validities accepted by a logical theory. In the present paper, I depart from Laudan's reticulated model of science to analyze one aspect of this problem, namely of the role of logical data within the process of revision of logical theories. For this, I argue that the ubiquitous nature of logical data is responsible for the proliferation of several (...) distinct methodologies for logical theories. The resulting picture is coherent with the Laudanean view that agreement and disagreement between scientific theories take place at different levels. From this perspective, one is able to articulate other kinds of divergence that considers not only the inferential aspects of a given logical theory, but also the epistemic aims and the methodological choices that drive its development. (shrink)

Radical glut and gap theorists deny—in opposite ways—that the liar sentence has exactly one of the two values true and not true. I describe a scenario where a signalman finds himself in a situation analogous to the liar paradox: if he lights a fire at a certain time, that is analogous to the liar being true, and if he does not, that is analogous to the liar not being true. It is obvious that he must make exactly one of those (...) states of affairs come about. It is argued that there are no relevant differences between the liar and the signalman’s dilemma, implying that the glut and gap theorists are wrong about the former. A further point is that whether or not the liar is true/the signalman lights the fire, language/the signalman is misleading relative to the conditions under which the liar/the fire “ought” to be true/lit. (shrink)

We explore a ‘Neo-Cartesian’ account of divine ultimacy that raises the concept of God to its ultimate level of abstraction so that we can do away with even the question of his existence. Our starting point is God’s relation to the logical and metaphysical order of reality and the views of Descartes and Leibniz on this topic. While Descartes held the seemingly bizarre view that the eternal truths are freely created by God, Leibniz stands for the mainstream view that the (...) eternal truths are grounded in God’s nature. We argue that the implausibility of Descartes’ doctrine stems mainly from the assumption that there is a non-epistemic notion of absolute necessity that constitutes the ultimate court of appeal for all modal questions and that this assumption is questionable. We also question the assumption that God’s ultimacy merely requires that all reality be grounded in God in the sense of mere explanation, so that it suffices if the necessary truths are grounded in God’s nature but not in God’s will. This will lead us to a reassessment of Descartes’ position. In the final and main part of the paper, we push Descartes’ doctrine of the creation of the eternal truths to its ‘logical’ conclusion with the aim of getting to a novel conception of ‘God.’. (shrink)

A semantic solution to the liar paradox (“This statement is not true”) is presented in this article. Since the liar paradox seems to evince a contradiction, the principle of non-contradiction is preliminarily discussed, in order to determine whether dismissing this principle may be reason enough to stop considering the liar paradox a problem. No conclusive outcome with respect to the value of this principle is aspired to here, so that the inquiry is not concluded at this point and the option (...) to explore an alternative, semantic, solution remains open. This proposed solution is focused on what the liar paradox expresses and what it fails to express. (shrink)

Realist dialetheism is the view that there are contradictions in reality. One argument against this idea says that it is impossible because it has to make room for the possibility of a trivial reality, which is metaphysically impossible. Another argument against it says that the metaphysical structure of reality is such that it is impossible to have contradictions in it. I argue here that both arguments fail to establish the impossibility of realist dialetheism because they are based on a misconception (...) about the notions of negation and contradiction, which leads them, in the first case, to wrongly hold that dialetheism has to be compatible with trivialism, and, in the second case, to assume that the validity of the Aristotelian principle of non-contradiction prevents the existence of dialetheias. (shrink)

Philosophers of science often assume that logically equivalent theories are theoretically equivalent. I argue that two theses, anti-exceptionalism about logic (which says, roughly, that logic is not a priori, that it is revisable, and that it is not special or set apart from other human inquiry) and logical realism (which says, roughly, that differences in logic reflect genuine metaphysical differences in the world), make trouble for both this commitment and the closely related commitment to theories being closed under logical consequence. (...) I provide three arguments. The first two show that anti-exceptionalism about logic provides an epistemic challenge to both the closure and the equivalence claims; the third shows that logical realism provides a metaphysical challenge to both the closure and the equivalence claims. Along the way, I show that there are important methodological upshots for metaphysicians and philosophers of logic. In particular, there are lessons to be drawn about certain conceptions of naturalism as constraining the possibilities for metaphysics and the philosophy of logic. (shrink)

Logical abductivism features in the recent literature as a _new epistemology_ for logic, in connection with logical anti-exceptionalism. According to this account, (i) logical knowledge is obtained by the justified _choice_ of a logical theory using abduction, which (ii) _replaces_ problematic approaches in traditional logical epistemology. We argue that such claims are not properly warranted; they conflate justification and theory choice methods. Abduction requires that one starts with _justified data_, and justification, in such cases, needs to appeal to sources that (...) are not granted by abduction. In this sense, abduction cannot be all there is to the epistemology of logic. Some abductivists, we shall see, even appeal to methods of the traditional epistemology to obtain the data. Keeping justification and theory choice separated may contribute to avoid obscurities in discussion of the nature of data in logic and in understanding more clearly how to frame the anti-exceptional nature of logic. (shrink)

Recently the functional model of reduction has become something like the standard model of reduction in philosophy of mind. In this paper, I argue that the functional model fails as an account of reduction due to problems related to three key concepts: functionalization, realization and causation. I further argue that if we try to revise the model in order to make it more coherent and scientifically plausible, the result is merely a simplified version of what in philosophy of science is (...) known as mechanistic explanation. Hence, instead of analyzing reduction in philosophy of mind in terms of functional reduction, it should be analyzed in terms of mechanistic explanation. (shrink)

The paper deals with such a modification of genuine modal realism as to accommodate impossible worlds into its ontology. First of all, the theory of modal realism is presented. Next, several motivations for the acceptance of impossible worlds are adduced. Furthermore, Lewis’s argument against impossible worlds is denied. Then, it is argued that the same methodology as in the case of possible worlds can be used when impossibilia are at issue. Finally, the theory of extended modal realism is formulated.

I sketch a philosophical program called ‘Empirical Fundamentalism,’ whose signature feature is the extensive use of a distinction between fundamental and derivative reality. Within the framework of Empirical Fundamentalism, derivative reality is treated as an abstraction from fundamental reality. I show how one can understand reduction and supervenience in terms of abstraction, and then I apply the introduced machinery to understand the relation between water and H2O, mental states and brain states, and so on. The conclusion is that such relations (...) can be understood either as metaphysical contingencies or as necessary type-identities. (shrink)

Rejectivism is one of the most influential embodiments of pragmatism within contemporary philosophy of logic, advancing an explanation of the meaning of a logical notion, negation, in terms of the speech act of denial. This paper offers a challenge to rejectivism by proposing that in virtue of explaining negation in terms of denial, the rejectivist ought to be able to explain the concept of contradiction partially in terms of denial. It is argued that any failure to achieve this constitutes an (...) explanatory failure on the part of rejectivism, and reasons are then provided to doubt that the challenge can be successfully met. (shrink)

Featuring fourteen new essays from an international team of renowned contributors, this volume explores the key issues, debates and questions in the metaphysics of logic. The book is structured in three parts, looking first at the main positions in the nature of logic, such as realism, pluralism, relativism, objectivity, nihilism, conceptualism, and conventionalism, then focusing on historical topics such as the medieval Aristotelian view of logic, the problem of universals, and Bolzano's logical realism. The final section tackles specific issues such (...) as glutty theories, contradiction, the metaphysical conception of logical truth, and the possible revision of logic. The volume will provide readers with a rich and wide-ranging survey, a valuable digest of the many views in this area, and a long overdue investigation of logic's relationship to us and the world. It will be of interest to a wide range of scholars and students of philosophy, logic, and mathematics. (shrink)

The view that contradictions cannot be true has been part of accepted philosophical theory since at least the time of Aristotle. In this regard, it is almost unique in the history of philosophy. Only in the last forty years has the view been systematically challenged with the advent of dialetheism. Since Graham Priest introduced dialetheism as a solution to certain self-referential paradoxes, the possibility of true contradictions has been a live issue in the philosophy of logic. Yet, despite the arguments (...) advanced by dialetheists, many logicians and philosophers still hold the opinion that contradictions cannot be true. -/- Rather than advocating the truth of certain contradictions, this thesis offers a different challenge to the classical logician. By showing that it can be philosophically coherent to propose that true contradictions are metaphysically possible, the thesis suggests that the classical logician must do more than she currently has to justify her confidence in the impossibility of true contradictions. Simply fighting off the dialetheist’s putative examples of true contradictions at the actual world isn’t enough to justify the classical logician’s conclusion that true contradictions are impossible. -/- To aid the thesis dialectically, we introduce a new position, absolutism, which hypothesises that it’s metaphysically possible for at least one contradiction to be true, contrasting with the dialetheic hypothesis that some contradictions are true in the actual world. We demonstrate that absolutism can be given a philosophically coherent interpretation, an appropriate logic, and that certain criticisms are completely toothless against absolutism. The challenge put to the classical logician is then: On what logical or philosophical grounds can we rule out the metaphysical possibility of true contradictions? (shrink)

The Heythrop Journal, Volume 63, Issue 3, Page 378-385, May 2022.

[full article, abstract in English; only abstract in Lithuanian] This paper investigates a particular strategy for establishing the deep connection between metaphysics and logic using Aristotle’s principle of non-contradiction and the theory of predication. The decisive move, according to this strategy, is to formulate and interpret the said principle as a metaphysical principle. In this paper, it is argued that: despite the strategy’s initial appeal, a successful argument still needs to be made in order to fully establish that metaphysics and (...) logic are deeply connected, and the theory of predication is more fundamental than the principle of non-contradiction. The main reason for above is that the strategy is prone to a very powerful objection that Aristotle’s criterion of primary substance is inconsistent. The main reason for above is that the principle of non-contradiction itself is best explained using the theory of predication. In addition, it is the theory of predication that does all the important explanatory work in the context of Aristotle’s philosophical theory. (shrink)