No one denies that time and space are different; and it is easy to catalog differences between them. I can point my finger toward the west, but I can’t point my finger toward the future. If I choose, I can now move to the left, but I cannot now choose to move toward the past. And (as D. C. Williams points out) for many of us, our attitudes toward time differ from our attitudes toward space. We want to maximize our (...) temporal extent and minimize our spatial extent: we want to live as long as possible but we want to be thin.1 But these differences are not very deep, and don’t get at the essence of the difference between time and space. That’s what I want to understand: I want to know what makes time different from space. I want to know which difference is the fundamental difference between them. (shrink)

This paper proposes a new reductive theory of modality, called the moodless theory of modality. This theory, and not modal realism, is the closest modal analogue of the tenseless theory of time. So, if the tenseless theory is true, and the temporality–modality analogy is good, it is the moodless theory that follows. I also argue that the moodless theory, considered on its own, is better than modal realism: arguments often thought to be decisive against modal realism are weak against it.

It is widely believed that shapes are intrinsic properties. But this claim is hard to defend. I survey all known theories of shape properties, and argue that each theory is either incompatible with the claim that shapes are intrinsic, or can be shown to be false.

The Causal Exclusion Problem is raised in many domains, including in the metaphysics of macroscopic objects. If there is a complete explanation of macroscopic effects in terms of the microscopic entities that compose macroscopic objects, then the efficacy of the macroscopic will be threatened with exclusion. I argue that we can avoid the problem if we accept that macroscopic objects are ontically vague. Then, it is indeterminate which collection of microscopic entities compose them, and so information about microscopic entities is (...) insufficient to provide a complete explanation of certain properties of macroscopic objects. After outlining this solution, I consider several objections. (shrink)

Elizabeth Barnes and Mari Mikkola raise the important question of whether certain recent approaches to metaphysics exclude feminist metaphysics. My own approach does not, or so I argue. I do define “substantive” questions in terms of fundamentality; and the concepts of feminist metaphysics are nonfundamental. But my definition does not count a question as being nonsubstantive simply because it involves nonfundamental concepts. Questions about the causal structure of the world, including the causal structure of the social world, are generally substantive (...) because their answers are not sensitive to any alternate, equally good conceptual choices we could have made. I also argue that such questions are substantive regardless of the ontology of social kinds. (shrink)

This is a symposium on my book, Writing the Book of the World, containing a precis from me, criticisms from Contessa, Merricks, and Schaffer, and replies by me.

Michael Jubien’s Ontology, Modality, and the Fallacy of Reference is an interesting and lively discussion of those three topics. In ontology, Jubien defends, to a first approximation, a Quinean conception: a world of objects that may be arbitrarily sliced or summed. Slicing yields temporal parts; summing yields aggregates, or fusions. Jubien is very unQuinean in his explicit Platonism regarding properties and propositions, but concerns about abstracta are peripheral to much of the argumentation in the book.1 His version of the doctrine (...) that arbitrary mereological sums exist is nonstandard in that he views it as a convention (albeit a useful one) that we treat sums of objects as themselves being objects. Indeed, he views the concept of objecthood itself as being conventional. The world consists fundamentally of stuff, which we divide into things in any way that suits our purposes. In modality, Jubien’s views are to a first approximation Chisholmian: he holds the doctrine of mereological essentialism, according to which anything.. (shrink)

A property, F, is maximal i?, roughly, large parts of an F are not themselves Fs. Maximal properties are typically extrinsic, for their instantiation by x depends on what larger things x is part of. This makes trouble for a recent argument against microphysical superve- nience by Trenton Merricks. The argument assumes that conscious- ness is an intrinsic property, whereas consciousness is in fact maximal and extrinsic.

Exotic ontologies are all the rage. Distant from common sense and often science as well, views like mereological essentialism, nihilism, and fourdimensionalism appeal to our desire to avoid arbitrariness, anthropocentrism, and metaphysical conundrums.1 Such views are defensible only if they are materially adequate, only if they can “reconstruct” the world of common sense and science. (No disrespect to the heroic metaphysicians of antiquity, but this world is not just an illusion.) In the world of common sense and science, bicycles survive (...) changes in their parts, billiard balls strike one another, and nothing travels faster than light. The mereological essentialist denies the rst, but offers this replacement: “there exist successions of numerically distinct, but appropriately related, bicycles with different parts” (Chisholm, , chapter ). The nihilist denies the second, but offers this replacement: “there exist X s and Y s such that the X s are arranged billiard-ball-wise, the Y s are also arranged billiard-ball-wise, and the X s strike the Y s”.2 The four-dimensionalist denies the third, but offers this replacement: “no sequences of matter-stages that are related by genidentity travel faster than light”.3 There is room for disagreement over what exactly “reconstruction” amounts to, but at a minimum: when a metaphysical theory reconstructs ordinary sentences φ1. . . as replacement sentences ψ1. . . , ordinary and scienti c evidence must not refute the view that, strictly speaking, it is ψ1. . . rather than φ1. . . that are true. The metaphysician needs reconstruction in order to face the tribunal of experience. An intriguing newcomer to the contemporary scene is the ancient doctrine of monism, the claim that “reality is one”.4 I will argue that, contrary to.. (shrink)

I argue that metaphysical views of material objects should be understood as 'packages', rather than individual claims, where the other parts of the package include how the theory addresses 'recalcitant data', and that when the packages meet certain general desiderata - which all of the currently competing views *can* meet - there is nothing in the world that could make one of the theories true as opposed to any of the others.

Eli Hirsch has argued in many places that non-commonsensical ontological claims just couldn't be true, since there is strong metasemantic pressure to charitably interpret natural language---correct interpretations must, unless all else is highly unequal, count a sentence (especially a perceptual sentence) as true if ordinary speakers regard it as being obviously true. In previous work I replied that ontologists can stipulatively introduce a new language, "Ontologese", that is exempt from this pressure toward charity. Hirsch has recently objected to this proposal; (...) this paper is my reply. (shrink)

Some philosophers believe that everyday objects are 4-dimensional spacetime worms, that a person (for example) persists through time by having temporal parts, or stages, at each moment of her existence. None of these stages is identical to the person herself; rather, she is the aggregate of all her temporal parts.1 Others accept “three dimensionalism”, rejecting stages in favor of the notion that persons “endure”, or are “wholly present” throughout their lives.2 I aim to defend an apparently radical third view: not (...) only do I accept person stages; I claim that we are stages.3 Likewise for other objects of our everyday ontology: statues are statue-stages, coins are coin-stages, etc. At one level, I accept the ontology of the worm view. I believe in spacetime worms, since I believe in temporal parts and aggregates of things I believe in. I.. (shrink)

In my book Four-dimensionalism (chapter 4, section 9), I argued that fourdimensionalism – the doctrine of temporal parts – follows from several other premises, chief among which is the premise that existence is never vague. Kathrin Koslicki (preceding article) claims that the argument fails since its crucial premise is unsupported, and is dialectically inappropriate to assume in the context of arguing for four-dimensionalism. Since the relationship between four-dimensionalism and the non-vagueness of existence is not perfectly transparent, I think the argument (...) would retain some interest even if the premise were wholly unsupported; it would show that anyone who accepts that premise (which seems reasonable enough to me though perhaps not to others) must accept four-dimensionalism. Still, Koslicki is right that my defense of the premise was thin. So I will now try to do better. The new defense will have further premises, which could ultimately be rejected by opponents of four-dimensionalism, and so the argument retains the form: anyone who thinks certain things (which seem reasonable enough to me though perhaps not to others) must believe four-dimensionalism. But that’s metaphysics for you. I should also say that, in addition to the material on vague existence, there is more in Koslicki’s excellent paper which I cannot discuss here. I agree with much of it;1 and where we disagree there are formidable challenges, some of which I hope to address in the future. (shrink)

Many people believe that for someone to now be responsible for some past action, the agent of that action and the responsible agent now must be one and the same person. In other words, many people that moral responsibility presupposes numerical personal identity. In this paper, I show why this platitude is false. I then suggest an account of what actual metaphysical relationship moral responsibility presupposes instead.

Many philosophers have taken there to be an important relation between personal identity and several of our practical concerns (among them moral responsibility, compensation, and self-concern). I articulate four natural methodological assumptions made by those wanting to construct a theory of the relation between identity and practical concerns, and I point out powerful objections to each assumption, objections constituting serious methodological obstacles to the overall project. I then attempt to offer replies to each general objection in a way that leaves (...) the project intact, albeit significantly changed. Perhaps the most important change stems from the recognition that the practical concerns motivating investigation into personal identity turn out to be not univocal, as is typically thought, such that each of the different practical concerns may actually be related to personal identity in very different ways. (shrink)

In this introduction to the special issue of Theoretical Medicine and Bioethics on the topic of personal identity and bioethics, I provide a background for the topic and then discuss the contributions in the special issue by Eric Olson, Marya Schechtman, Tim Campbell and Jeff McMahan, James Delaney and David Hershenov, and David DeGrazia.

Several philosophers have recently defended Causal Essentialism—the view that every property confers causal powers, and whatever powers it confers, it confers essentially. I argue that on the face of it, Causal Essentialism implies a form of Monism, and in particular, the thesis I call ‘Mereological Monism’: that there is some concretum that is a part of every concretum. However, there are three escape routes, three views which are such that if one of them is true, Causal Essentialism does not imply (...) any form of Monism at all. I survey the costs associated with taking these escape routes along with the costs associated with accepting Mereological Monism. (shrink)

Truthmakers are supposed to explain the truth of propositions, but it is unclear what kind of explanation truthmakers can provide. In this paper, I argue that ‘truthmaker explanations’ conflate two different explanatory projects. The first project is essentially concerned with truth, while the second project is concerned with reductive explanation. It is the latter project, I maintain, which is really central to truthmaking theory. On this basis, a general account of truthmaking can be formulated, which, when combined with a specific (...) theory of reduction (the ‘conceptual entailment approach’), yields a new analysis of truthmaking. This analysis is intuitively appealing and avoids the problem of necessary truths, which poses a serious obstacle for standard accounts. (shrink)

If ordinary objects have temporal parts, then temporal predications have the following truth conditions: necessarily, ( a is F) at t iff a has a temporal part that is located at t and that is F. If ordinary objects have temporal counterparts, then, necessarily, ( a is F) at t iff a has a temporal counterpart that is located at t and that is F. The temporal-parts account allows temporal predication to be closed under the parthood relation: since all that (...) is required to be F at t is to have a temporal part, a t , that is located at t and that is F, every object that has a t as a temporal part is F at t . Similarly for the temporal-counterparts account. Both closure under parthood and closure under counterparthood are shown to have unacceptable consequences. Then strategies for avoiding closure are considered and rejected. (shrink)

Perdurance is a mode of persistence. The heart of perdurance is a space-time analogy: a perduring object is extended in time in a way that is analogous to how a composite object is extended in space. This paper is a discussion of perdurance in light of the distinction between mereologically structured and unstructured objects. I show that while the standard formulation of perdurance captures the space-time analogy for unstructured objects, it fails to capture the space-time analogy for temporally and spatially (...) structured objects. I conclude that there are substantially different ways for an object to be space-like temporally extended. (shrink)

As I will use the term, an object is a mereological sum of some things just in case those things compose it simply in virtue of existing. In the first half of this paper, I argue that there are no sums. The key premise for this conclusion relies on a constraint on what, in certain cases, it takes for something to ground, or metaphysically explain, something else. In the second half, I argue that in light of my argument against sums, (...) Universalism, which is perhaps the most widely accepted answer to the Special Composition Question, is false. (shrink)

In this paper, I both propose and discuss a novel account of truthmaking. I begin by showing what truthmaking is not: it is not grounding and it is not correspondence. I then show what truthmaking is by offering an account that appeals both to grounding and what I call ‘deep correspondence’. After I present the account and show that it is an account that unifies, I put it to work by showing how it can overcome an objection to truthmaking, how (...) we can get truthmaking from correspondence, what it says about truthmaker necessitation, and how it can explain a connection between truthmaker maximalism and pluralism about truth. (shrink)

The statue and the lump of clay that constitutes it fail to share all of their kind and modal properties. Therefore, by Leibniz’s Law, the statue is not the lump. Question: What grounds the kind and modal differences between the statue and the lump? In virtue of what is it that the lump of clay, but not the statue, can survive being smashed? This is the grounding problem. Now a number of solutions to the grounding problem require that we substantially (...) revise our view of reality. In this paper, I provide a solution to this problem that does not require such a revision. I then show how my solution to the grounding problem can solve a related problem and answer a related question. The upshot is that the solution I offer is not only non-revisionary, but also fruitful. (shrink)

What is the relation between a clay statue andthe lump of clay from which it is made? According to the defender of the standardaccount, the statue and the lump are distinct,enduring objects that share the same spatiallocation whenever they both exist. Suchobjects also seem to share the samemicrophysical structure whenever they bothexist. This leads to the standard objection tothe standard account: if the statue and thelump of clay have the same microphysicalstructure whenever they both exist, how canthey differ in their (...) de re temporalproperties, de re modal properties and soon? In this paper I develop amereological answer to this question – thestatue and the lump differ with respect totheir parts and this explains theirdifference with respect to de re temporalproperties, de re modal properties andthe like. (shrink)

When do the folk think that material objects persist? Many metaphysicians have wanted a view which fits with folk intuitions, yet there is little agreement about what the folk intuit. I provide a range of empirical evidence which suggests that the folk operate with a teleological view of persistence: the folk tend to intuit that a material object survives alterations when its function is preserved. Given that the folk operate with a teleological view of persistence, I argue for a debunking (...) explanation of folk intuitions, concluding that metaphysicians should dismiss folk intuitions as tied into a benighted view of nature. (shrink)

In this paper I argue that the growing block theory of time has rather surprising, and hitherto unexplored, explanatory benefits when it comes to certain enduring philosophical puzzles concerning death. In particular, I claim the growing block theorist has readily available and convincing answers to the following questions: Why is it an evil to be dead but not an evil to be not yet born? How can death be an evil for the dead if they no longer exist to suffer (...) it? When is death an evil for the one who dies? The ability to give such answers is a significant, but by no means decisive, advantage for the growing block view of time. (shrink)

In this paper I argue for a view of groups, things like teams, committees, clubs and courts. I begin by examining features all groups seem to share. I formulate a list of six features of groups that serve as criteria any adequate theory of groups must capture. Next, I examine four of the most prominent views of groups currently on offer—that groups are non-singular pluralities, fusions, aggregates and sets. I argue that each fails to capture one or more of the (...) criteria. Last, I develop a view of groups as realizations of structures. The view has two components. First, groups are entities with structure. Second, since groups are concreta, they exist only when a group structure is realized. A structure is realized when each of its functionally defined nodes or places are occupied. I show how such a view captures the six criteria for groups, which no other view of groups adequately does, while offering a substantive answer to the question, “What are groups?”. (shrink)

This article considers how people judge the identity of objects (e.g., how people decide that a description of an object at one time, t₀, belongs to the same object as a description of it at another time, t₁). The authors propose a causal continuer model for these judgments, based on an earlier theory by Nozick (1981). According to this model, the 2 descriptions belong to the same object if (a) the object at t₁ is among those that are causally close (...) enough to be genuine continuers of the original and (b) it is the closest of these close-enough contenders. A quantitative version of the model makes accurate predictions about judgments of which a pair of objects is identical to an original (Experiments 1 and 2). The model makes correct qualitative predictions about identity across radical disassembly (Experiment 1) as well as more ordinary transformations (Experiments 2 and 3). (shrink)

A recently published hypothesis on the nature of time by physicist Richard A. Muller seeks to provide an objective account of the present moment and the ‘flow’ of time. Muller also claims that his hypothesis makes testable predictions. It is shown that the predictions offered cannot be used to test Muller’s hypothesis, that the hypothesis does not rate scientific status, has a number of questionable metaphysical premises, and is merely a re-fashioning of the Growing Block theory of time.

There is an interesting parallel between two debates in different domains of contemporary analytic philosophy. One is the endurantism– perdurantism, or three-dimensionalism vs. four-dimensionalism, debate in analytic metaphysics. The other is the debate on the species problem in philosophy of biology. In this paper I attempt to cross-fertilize these debates with the aim of exploiting some of the potential that the two debates have to advance each other. I address two issues. First, I explore what the case of species implies (...) regarding the feasibility of particular positions in the endurantism– perdurantism debate. I argue that the case of species casts doubt on the recent claim that three-dimensionalism and four-dimensionalism are equivalent descriptions of the same underlying reality. Second, and conversely, I examine whether the metaphysical worry about three-dimensionalism and four-dimensionalism can help us to better understand the nature of biological species. I show that analyzing the thesis that species are individuals against the background of the endurantism– perdurantism debate allows us to explicate two different ways in which this thesis can be interpreted. (shrink)

In this paper, I take inspiration from some themes in Ann Murphy’s recent book, Violence and the Philosophical Imaginary, especially her argument that philosophy’s identity and relation to itself depends on an intimate relationship with that which is designated as not itself, the latter of which is a potential source of shame that calls for some form of response. I argue that this shame is particularly acute in regard to the natural sciences, which have gone on in various ways to (...) distance themselves from their progenitor discipline and to achieve both agreement and technical progress in a way that could never be said of philosophy. I trace out some of the reactions to this shame that have dominated in the twentieth century and been a factor in the so-called analytic-continental ‘divide’. The options here are many and varied, but they range from cannibalism, scientific naturalism, or some kind of irenic separatism about methods or domains such that science and philosophy do not encroach upon the territory of each other. My aims here are mainly diagnostic, but I will indicate where I think that certain responses to this shame are unproductive and unhelpful, with divergent weaknesses associated with the traditions that have come to be labelled ‘analytic’ and ‘continental’ respectively. My tacit suggestion, then, is that philosophy needs to become post-analytic and meta-continental, but I will also briefly criticize some recent efforts to do precisely this in what is sometimes called the ‘scientific turn’ in contemporary continental philosophy. (shrink)

It is widely believed that presentism is compatible with both a libertarian view of human freedom and an unrestricted principle of bivalence. I argue that, in fact, presentists must choose between bivalence and libertarianism: if presentism is true, then either the future is open or no one is free in the way that libertarians understand freedom.

Impostors are pseudo-problems masquerading as genuine problems. Impostors should be exposed. The problem of change appears genuine. But some, such as Hofweber ( 2009 ) and Rychter ( 2009 ), have recently denounced it as an impostor. They allege that it is mysterious how to answer the meta - problem of saying what problem it is: for even if any problem is genuinely about change per se, they argue, it is either empirical or trivially dissolved by conceptual analysis. There is (...) indeed an impostor in our midst. But it is the meta-problem of change. I defend the appearance that the problem of change is a genuine metaphysical problem about change. This vindicates philosophers’ lasting interest in it. It also illuminates what makes a problem metaphysical, how metaphysics relates to other inquiries, and how best to respond to attempts to undermine metaphysical problems. (shrink)

I defend (metaphysical) ground against recent, unanswered objections aiming to dismiss it from serious philosophical inquiry. Interest in ground stems from its role in the venerable metaphysical project of identifying which facts hold in virtue of others. Recent work on ground focuses on regimenting it. But many reject ground itself, seeing regimentation as yet another misguided attempt to regiment a bad idea (like phlogiston or astrology). I defend ground directly against objections that it is confused, incoherent, or fruitless. This vindicates (...) the very attempt to regiment ground. It also refocuses our attention on the genuine open questions about ground and away from the distracting, unpersuasive reasons for dismissing them. (shrink)

David Lewis’s counterpart-theoretic semantics for quantified modal logic is motivated originally by worries about identifying objects across possible worlds; the counterpart relation is grounded more cautiously on comparative similarity. The possibility of contingent identity is an unsought -- and in some eyes, unwelcome -- consequence of this approach. In this paper I motivate a Kripkean counterpart theory by way of defending the prior, pre-theoretical, coherence of contingent directness. Contingent identity follows for free. The theory is Kripkean in that the counterpart (...) relation is in a sense stipulated rather than grounded on similarity, and is such that no object has more than one counterpart at a world. This avoids a number of objections Fara and Williamson have recently levelled against counterpart theory generally; their other objections are addressed by enriching the theory with special quantifiers and actuality operators. (shrink)

Lewis’s [1968] counterpart theory (LCT for short), motivated by his modal realism, made its appearance within a year of Chisholm’s modal paradox [1967]. We are not modal realists, but we argue that a satisfactory resolution to the paradox calls for a counterpart-theoretic (CT-)semantics. We make our case by showing that the Chandler–Salmon strategy of denying the S4 axiom [◊◊ψ →◊ψ] is inadequate to resolve the paradox – we take on Salmon’s attempts to defend that strategy against objects from Lewis and (...) Williamson. We then consider three substantially different CT-approaches: Lewis’s LCT, Forbes’s (FCT), including his fuzzy version, and Ramachandran’s (RCT). We argue that the best approach is a mish-mash of FCT and RCT. (shrink)

This paper draws a distinction between the existential quantifier and the symbol ‘∃’ used to express it, on the one hand, and existence and ‘exists’, on the other. It argues that some popular arguments in metaphysics, including arguments against vague existence and arguments against deflationary metaontology (which views ontological disputes as lacking substance), are guilty of fudging this distinction. The paper draws some lessons for metaphysical debate about existence and highlights some heretofore ignored and attractive positions in logical space.

Core principles of mereology have been questioned by appealing to time travel scenarios. This paper questions the methodology of employing time travel scenarios to argue against mereology. We show some time travel scenarios are structurally equivalent to more standard ones not involving time travel; and that the three main theories about persistence through time can each solve both the time travel scenario as well as the structurally similar classical scenario. Time travel scenarios that are not similar to more standard arguments (...) are instead problematic because they are open to different, incompatible interpretations. We conclude that compared to the classical arguments against mereological principles, time travel scenarios do not add anything new. (shrink)

It is widely assumed that if ontological disputes turn out to be verbal they ought to be dismissed. I dissociate the semantic question concerning the verbalness of ontological disputes from the pragmatic question on whether they ought to be dismissed. I argue that in the context of ontological disputes ontologists ought to be taken to communicate views with conflicting ontological commitments even if it turns out that on the correct view of semantics they fail to literally-express their disagreement. I argue, (...) that is, against dismissing ontological disputes on grounds of verbalness. This serves to discharge the ongoing debate on the verbalness of ontological disputes from the metaontological consequences typically associated with it. (shrink)

I defend the view that ordinary objects like statues are identical to the pieces of matter from which they are made. I argue that ordinary speakers assert sentences such as ‘this statue is a molded piece of clay’. This suggests that speakers believe propositions which entail that ordinary objects such as statues are the pieces matter from which they are made, and therefore pluralism contradicts ordinary beliefs. The dominant response to this argument purports to find an ambiguity in the word (...) ‘is’, such that ‘is’ in these sentences means the same as ‘constitutes or is constituted by’. I will use standard tests for ambiguity to argue that this strategy fails. I then explore and reject other responses to the argument. (shrink)

This paper considers a problem for dynamic presentism that has received little attention: its apparent inability to accommodate the duration of events (such as conscious experiences). After outlining the problem, I defend presentism from it. This defence proceeds in two stages. First, I argue the objection rests on a faulty assumption: that duration is temporal extension. The paper challenges that assumption on several different ways of conceiving of temporal extension. This is the negative case and forms the bulk of the (...) paper. Second, after diagnosing the error leading to the identification of duration with temporal extension, I outline a new presentist-friendly account of duration that avoids the problem. In particular, a non-reductive account of duration is offered that treats it as a primitive quality which bestows its possessor with a certain modal quality: that the possessor potentially does not change whilst there are changes in its environs. This is the positive case. Together the positive and negative cases provide presentism with an interesting and novel way of overcoming the problem of duration. (shrink)

In this paper, I develop an argument against eternalism, which is similar to the widely discussed grounding problem for presentism. It has recently been argued by many that presentism should be rejected on grounds that its sparse ontology is not suited to underwrite the healthy dose of realism we all share about the past. My aim basically is to add a new twist to the debate, by showing that actually eternalists are no better off than their rivals. In particular, I (...) argue that the eternalist’s ontology does not have the appropriate shape to ground true propositions about the past. (shrink)

According to four dimensionalism, the material world is divided into momentary stages. In a four-dimensional world, which objects are the ordinary things, the things we normally name and quantify over? Aggregates of stages, according to most four-dimensionalists, but according to stage theorists (or exdurantists), ordinary objects are instead to be identified with the stages themselves. (A temporal counterpart theoretic account of de re temporal predication is then given.) This paper argues that a stage theorist is best positioned to accept David (...) Lewis's argument from temporary intrinsics for four-dimensionalism, since stage theorists are the only four-dimensionalists who attribute monadic temporary intrinsic properties to ordinary things. (shrink)

Philosophers of science have often favoured reductive approaches to how-possibly explanation. This article identifies three alternative conceptions making how-possibly explanation an interesting phenomenon in its own right. The first variety approaches “how possibly X?” by showing that X is not epistemically impossible. This can sometimes be achieved by removing misunderstandings concerning the implications of one’s current belief system but involves characteristically a modification of this belief system so that acceptance of X does not result in contradiction. The second variety offers (...) a potential how-explanation of X. It is usually followed by a range of further potential how-explanations of the same phenomenon. In recent literature the factual claims implied by the second variety have been downplayed whereas the heuristic role of mapping the space of conceptual possibilities has been emphasized. I will focus especially on this truth-bracketing sense of potentiality when looking closer at the second variety in the paper. The third variety has attracted less interest. It presents a partial how-explanation of X. Typically it aims to establish the existence of a mechanism by which X could be and was generated. The third conception stands out as the natural alternative for the advocate of ontic how-possibly explanations. This article transfers Salmon’s view that explanation-concepts can be broadly divided into epistemic, modal, and ontic to the context of how-possibly explanations. Moreover, it is argued that each of the three above-mentioned varieties of how-possibly explanation occurs in science. To recognize this may be especially relevant for philosophers. We are often misled by the promises of various why-explanation accounts, and seem to have forgotten nearly everything about the diversity of how-possibly explanations. (shrink)