How to Derive a ‘Not’ from an ‘Is’: A Defense of the Incompatibility View of Negative Truths

Truthmaker maximalism is the claim that every truth has a truthmaker. The case of negative truths leads some philosophers to postulate negative states of affairs or to give up on truthmaker maximalism. This paper defends a version of the incompatibility view of negative truths. Negative truths can be made true by positive facts, and thus, truthmaker maximalism can be maintained without postulating negative states of affairs.     

Explaining modal intuition

The paper defends causal explanationism concerning our modal intuitions and judgments, and, in particular, the following claims. If a causally explainable mirroring or “pre-established harmony” between our mind and modal reality obtains, we are justified in believing it does. We do not hold our modal beliefs compulsively and blindly but with full subjective and objective justification. Therefore, causal explanation of our modal beliefs does not undermine rational trust in them. Explanation and trust support each other. In contrast, anti-explanationists (from Kant, through neo-wittgensteinians to T. Nagel and J. Pust), claim that causal explanation of intuitions and judgments undermines rational trust in them. They especially target causal explanation in terms of pre-established harmony between our mind, shaped by causal processes, and the underlying modal structure of reality. The paper argues against them. The argument builds upon the claim that the appeal to modal facts is indispensable for systematization and explanation of non-modal ones. Therefore, we should assume that modal facts exist and are not disjoint and isolated from actual facts. The modal structure of the universe intervenes in the non-modal reality. Causal processes indirectly carry information about deep modal structure. Any (reasonable candidate) causal explanation of our intuitional modal beliefs should start from this indirect contact with and information about modal facts. Therefore, if our intuitional modal beliefs are true and causally explainable (by a factual, non-modal explanans), they are true in virtue of the deep underlying modal structure. They are sensitive to modal reality and track it. We can come to know this fact, and thus strengthen our spontaneous trust in our modal intuitions.     

Truthmaker Internalism and the Mind-Dependence of Propositions

It is generally thought that truthmaking has to be an internal relation because if it weren’t, then, as David Armstrong argues, “everything may be a truthmaker for any truth” (1997: 198). Depending on whether we take an internal relation to be one that is necessitated by the mere existence of its terms (Armstrong 1997: 87 and 2004: 9) or one that supervenes on the intrinsic properties of its relata (Lewis 1986: 62), the truthbearers involved in the truthmaking relation must either have their contents essentially or intrinsically. In this paper, I examine Armstrong’s account (1973; 1997 and 2004), according to which what is made true at the fundamental level are mental state tokens. The conclusion is reached that such tokens have their contents neither essentially nor intrinsically, and so, are simply the wrong kind of entities to be made true internally.     

Necessitating Nominalism

It is argued that, if Armstrong is correct and truthmakers necessitate the truths they make true, then the truthmakers must include facts about the meanings of the words used to express those truths, and nominalism apparently results. This conclusion, no doubt unpalatable to Armstrong, is, it is claimed, the result of his having failed to distinguish sufficiently the meanings of words and the properties of things.     

The Problem of Universals, Realism, and God

There has been much discussion of late on what exactly the Problem of Universals is and is not. Of course answers to these questions and many more like it depend on what is supposed to be explained by a solution to the Problem of Universals. In this paper, I seek to establish two claims: first, that when the facts (explanada) to be explained and the kind of explanation needed are elucidated, it will be shown that the Problem of Universals is a real metaphysical problem, not a pseudo problem; secondly, the facts whose explanation posed the problem in the Problem of Universals still provide reason to think realism regarding universals is true, even if God exists.     

Remarks on Levy's reflection axiom

Adding higher types to set theory differs from adding inaccessible cardinals, in that higher type arguments apply to all sets rather than just ordinary ones. Levy's reflection axiom is justified, by considering the principle that we can pretend that the universe is a set, together with methods of Gaifman [8]. We reprove some results of Gaifman, and some facts about Levy's reflection axiom, including the fact that adding higher types yields no new theorems about sets. Some remarks on standard models are made. An obvious strengthening of Levy's axiom to higher types is considered, which implies the existence of indescribable cardinals. Other remarks about larger cardinals are made; some questions of Gloede [9] are settled. Finally we argue that the evidence for V = L is strong, and that CH is certainly true. MSC: 03E30, 03E55.     

Veber on knowledge and factuality

The article deals with the development of the philosophy of France Veber (1890–1975), the pupil of Meinong and a main Slovene philosopher. One of the most important threads of Veber’s philosophy is the consideration of knowledge and factuality, which may be seen as a driving force of its development. Veber’s philosophical development is usually divided into three phases: the object theory phase, the phase when he created his philosophy of a person as a creature at the crossing of the natural and the spiritual world, who as an active, not merely passive subject possesses her own causal powers, and the third phase, when he supplemented his earlier philosophy with the theory of a special side of our experience which he called hitting-upon-reality. It is a direct experience of reality, a special kind of intentionality, which is however fundamentally different from presentational intentionality, which alone is taken into account by object theory or phenomenology. The questions of knowledge and factuality are closely connected in Veber’s philosophy since, pace Veber, knowledge is a kind of, we may say, justified experience the object of which is a factual entity. Hence, if we want to understand what knowledge is, we must face the challenge of comprehending factuality. There are five stages to be noted in the development of his epistemology. The first two belong to his object theory phase, the third to his person phase, the fourth is characterised by his distinguishing and exploring truth and validity with regard to the thought about God, and the basis of the fifth phase lies in his theory of hitting-upon-reality. In Introduction to Philosophy and The System of Philosophy, that is in the year 1921, Veber believed that factuality (“truth,”) was a property of the object, which we do present, but we do not present the factuality of this factuality (that is why he distinguishes between the merely objective truths and truths that are in addition transcendental truths). In 1923, in The Problems of Contemporary Philosophy and in the work Science and Religion, he already rejected such a view. There is something that makes things factual, but that is a complete unknown X. Therefore we cannot even say what kind of an entity this factuality is. Some people would probably demand the following formulation: if X is an ultimate mystery, we should not claim even that it is an entity. In The Problems of Presentation Production (1928) Veber claimed that factuality is not a property since this would lead to a regressum ad infinitum. Philosophy (1930) related internally correct experience to personal will. In The Book about God (1934) he developed the thesis that factuality depends on the act of God. In The Question of Reality (1939) he importantly modified, developed and enriched the thesis that we do not present reality with his theory of immediate experience of (hitting upon) factuality.     

Primitive Disclosive Alethism

The contemporary debate about truth is polarized between deflationists and those who offer robust accounts of truth. I present a theory of truth called ‘Primitive Disclosive Alethism’ that occupies the middle ground between these two extremes. Contrary to deflationist claims, truth has a nature beyond its merely linguistic, expressive function. Truth is objective and non-epistemic, yet cannot be characterized in terms of correspondence. Primitive Disclosive Alethism offers a metaphysically satisfying explanation of our correspondence intuitions, while explaining why the concept of truth is an undefined primitive. The theory also explains why the T-schema offers the clearest expression of what makes a sentence true. I distinguish this theory from the Identity Theory of Truth which equates true propositions with facts.     

The Poisson random effect model for experience ratemaking: Limitations and alternative solutions

Poisson random effect models with a shared random effect have been widely used in actuarial science for analyzing the number of claims. In particular, the random effect is a key factor in a posteriori risk classification. However, the necessity of the random effect may not be properly assessed due to the dual role of the random effect; it affects both the marginal distribution of the number of claims and the dependence among the numbers of claims obtained from an individual over time. We first show that the score test for the nullity of the variance of the shared random effect can falsely indicate significant dependence among the numbers of claims even though they are independent. To mitigate this problem, we propose to separate the dual role of the random effect by introducing additional random effects to capture the overdispersion part, which are called saturated random effects. In order to circumvent heavy computational issues by the saturated random effects, we choose a gamma distribution for the saturated random effects because it gives the closed form of marginal distribution. In fact, this choice leads to the negative binomial random effect model that has been widely used for the analysis of frequency data. We show that safer conclusions about the a posteriori risk classification can be made based on the negative binomial mixed model under various situations. We also derive the score test as a sufficient condition for the existence of the a posteriori risk classification based on the proposed model.     

The price of quality claims

Quality claims and quality in fact of financial and industrial products as well as financial and business services are essential to entice and attract customers. For these reasons, firms are often tempted to assert claims that might or might not be met. These claims have risks which cannot always be prevented when interpreted as a ‘sure thing’ while in fact, quality performance is probabilistic. This paper considers a financial (utility based) approach to pricing a quality claim. To do so, we assume that ex‐ante, a true quality performance is defined by a density function while claims are advertised—setting expectations for a quality performance. On the basis of these assumptions we determine the price associated with such claims. Copyright © 2010 John Wiley & Sons, Ltd.     

Reconstructed Empiricism

According to Bas van Fraassen, scientific realists and anti-realists disagree about whether accepting a scientific theory involves believing that the theory is true. On van Fraassen’s own anti-realist empiricist position, accepting a theory involves believing only that the theory is correct in its claims about observable aspects of the world. However, a number of philosophers have argued that acceptance and belief cannot be distinguished and thus that the debate is either confused or trivially settled in favor of the realist. In addition, another set of philosophers have argued that van Fraassen’s empiricist position appeals to an unmotivated distinction between observable and unobservable aspects of the world. This paper aims to reconstruct a van Fraassen-style empiricism about scientific acceptance that avoids these two objections – reconstructed empiricism.     

Scepticism,context and modal reasoning

I analyze some classical solutions of the skeptical argument and some of their week points (especially the contextualist solution). First I have proposed some possible improvement of the contextualist solution (the introduction of the explicit-implicit belief and knowledge distinction beside the differences in the relevance of some counter-factual alternatives). However, this solution does not block too fast jumps of the everyday context (where empirical knowledge is possible) into skeptical context (where empirical knowledge is impossible). Then I analyze some formal analogies between some modal arguments on the contingency of empirical facts (and the world as whole) and the skeptical arguments against empirical knowledge. I try to show that the skeptical conclusion “Empirical knowledge does not exist” is logically coherent with the thesis that they are empirical facts and that we have true belief on them. In order to do that without contradictions I have to accept a non-classical definition of knowledge: S knows that p:= S is not justified to allow that non-p. Knowledge and justified allowance function here as some pseudo-theoretical concepts which allow only some partial and conditional definitions by some “empirical” terms and logical conditions.     

Identifiability of intermediate variables on causal paths

We discuss the discovery of causal mechanisms and identifiability of intermediate variables on a causal path. Different from variable selection, we try to distinguish intermediate variables on the causal path from other variables. It is also different from ordinary model selection approaches which do not concern the causal relationships and do not contain unobserved variables. We propose an approach for selecting a causal mechanism depicted by a directed acyclic graph (DAG) with an unobserved variable. We consider several causal networks, and discuss their identifiability by observed data. We show that causal mechanisms of linear structural equation models are not identifiable. Furthermore, we present that causal mechanisms of nonlinear models are identifiable, and we demonstrate the identifiability of causal mechanisms of quadratic equation models. Sensitivity analysis is conducted for the identifiability.     

The Gerber-Shiu function and the generalized Cramér-Lundberg model

In this paper we extend some results in Cramér [7] by considering the expected discounted penalty function as a generalization of the infinite time ruin probability. We consider his ruin theory model that allows the claim sizes to take positive as well as negative values. Depending on the sign of these amounts, they are interpreted either as claims made by insureds or as income from deceased annuitants, respectively. We then demonstrate that when the events’ arrival process is a renewal process, the Gerber-Shiu function satisfies a defective renewal equation. Subsequently, we consider some special cases such as when claims have exponential distribution or the arrival process is a compound Poisson process and annuity-related income has Erlang(n, β) distribution. We are then able to specify the parameter and the functions involved in the above-mentioned defective renewal equation.     

On factors of 4‐connected claw‐free graphs*

We consider the existence of several different kinds of factors in 4‐connected claw‐free graphs. This is motivated by the following two conjectures which are in fact equivalent by a recent result of the third author. Conjecture 1 (Thomassen): Every 4‐connected line graph is hamiltonian, i.e., has a connected 2‐factor. Conjecture 2 (Matthews and Sumner): Every 4‐connected claw‐free graph is hamiltonian. We first show that Conjecture 2 is true within the class of hourglass‐free graphs, i.e., graphs that do not contain an induced subgraph isomorphic to two triangles meeting in exactly one vertex. Next we show that a weaker form of Conjecture 2 is true, in which the conclusion is replaced by the conclusion that there exists a connected spanning subgraph in which each vertex has degree two or four. Finally we show that Conjectures 1 and 2 are equivalent to seemingly weaker conjectures in which the conclusion is replaced by the conclusion that there exists a spanning subgraph consisting of a bounded number of paths © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 125–136, 2001     

Reliabilism and Brains in Vats

According to epistemic internalism, the only facts that determine the justificational status of a belief are facts about the subject’s own mental states, like beliefs and experiences. Externalists instead hold that certain external facts, such as facts about the world or the reliability of a belief-producing mechanism, affect a belief’s justificational status. Some internalists argue that considerations about evil demon victims and brains in vats provide excellent reason to reject externalism: because these subjects are placed in epistemically unfavorable settings, externalism seems unable to account for the strong intuition that these subjects’ beliefs are nonetheless justified. I think these considerations do not at all help the internalist cause. I argue that by appealing to the anti-individualistic nature of perception, it can be shown that skeptical scenarios provide no reason to prefer internalism to externalism.     

Towards an Account of Epistemic Luck for Necessary Truths

Modal epistemologists parse modal conditions on knowledge in terms of metaphysical possibilities or ways the world might have been. This is problematic. Understanding modal conditions on knowledge this way has made modal epistemology, as currently worked out, unable to account for epistemic luck in the case of necessary truths, and unable to characterise widely discussed issues such as the problem of religious diversity and the perceived epistemological problem with knowledge of abstract objects. Moreover, there is reason to think that this is a congenital defect of orthodox modal epistemology. This way of characterising modal epistemology is however optional. It is shown that one can non-circularly characterise modal conditions on knowledge in terms of epistemic possibilities, or ways the world might be for the target agent. Characterising the anti-luck condition in terms of epistemic possibilities removes the impediment to understanding epistemic luck in the case of necessary truths and opens the door to using these conditions to shed new light on some longstanding epistemological problems.     

Exploring Diverse Accounts of Teacher Knowledge

This article explores the nature of teacher knowledge as it is portrayed by Schoenfeld's model of teaching. We attempt to situate Schoenfeld's work in the field of teacher knowledge and to elucidate the contribution that he makes to the growing body of research in this area. Towards this end, we explore two related issues. First, we distinguish between claims about the form of teacher knowledge and claims about the content of teacher knowledge. Second, we propose two families of theories of teacher knowledge, where each family shares common phenomena, methods, and theoretical forms. We argue that these two families capture much of the diversity that exists in the literature on teacher knowledge today. Our goal is to begin to develop a theoretical approach that will not only allow us to situate Schoenfeld's research, but that will also help us to compare existing theories with each other.     

Coupling vs. conductance for the Jerrum–Sinclair chain*

We address the following question: is the causal coupling method as strong as the conductance method in showing rapid mixing of Markov chains? A causal coupling is a coupling which uses only past and present information, but not information about the future. We answer the above question in the negative by showing that there exists a bipartite graph G such that any causal coupling argument on the Jerrum–Sinclair Markov chain for sampling almost uniformly from the set of perfect and near perfect matchings of G must necessarily take time exponential in the number of vertices in G. In contrast, the above Markov chain on G has been shown to mix in polynomial time using conductance arguments. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 1–17, 2001