The capacity to represent things to ourselves as possible plays a crucial role both in everyday thinking and in philosophical reasoning; this volume offers much-needed philosophical illumination of conceivability, possibility, and the relations between them.

There is a long tradition in philosophy of using a priori methods to draw conclusions about what is possible and what is necessary, and often in turn to draw conclusions about matters of substantive metaphysics. Arguments like this typically have three steps: first an epistemic claim , from there to a modal claim , and from there to a metaphysical claim.

The capacity to represent things to ourselves as possible plays a crucial role both in everyday thinking and in philosophical reasoning; this volume offers much-needed philosophical illumination of conceivability, possibility, and the relations between them. Thirteen leading philosophers present specially-written essays, and a substantial introduction is provided by the volume editors, who demonstrate the importance of these topics to a wide range of issues in contemporary philosophy.

The Humean view that conceivability entails possibility can be criticized via input from cognitive psychology. A mainstream view here has it that there are two candidate codings for mental representations (one of them being, according to some, reducible to the other): the linguistic and the pictorial, the difference between the two consisting in the degree of arbitrariness of the representation relation. If the conceivability of P at issue for Humeans involves the having of a linguistic mental representation, then (...) it is easy to show that we can conceive the impossible, for impossibilities can be represented by meaningful bits of language. If the conceivability of P amounts to the pictorial imaginability of a situation verifying P, then the question is whether the imagination at issue works purely qualitatively, that is, only by phenomenological resemblance with the imagined scenario. If so, the range of situations imaginable in this way is too limited to have a significant role in modal epistemology. If not, imagination will involve some arbitrary labeling component, which turns out to be sufficient for imagining the impossible. And if the relevant imagination is neither linguistic nor pictorial, Humeans will appear to resort to some representational magic, until they come up with a theory of a ‘third code’ for mental representations. (shrink)

Each year, tens of thousands of children are conceived with donated gametes (sperm or eggs). By some estimates, there are over one million donor-conceived people in the United States and, of course, many more the world over. Some know they are donor-conceived. Some do not. Some know the identity of their donors. Others never will. -/- Questions about what donor-conceived people should know about their genetic progenitors are hugely significant for literally millions of people, including donor-conceived people, their parents, and (...) donors. But the practice of gamete donation also provides a vivid occasion for thinking about questions that matter to everyone. What is the value of knowing who your genetic progenitors are? How are our identities bound up with knowing where we come from? What obligations do parents have to their children? And what makes someone a parent in the first place? -/- In Conceiving People: Identity, Genetics and Gamete Donation, Daniel Groll argues that people who plan to create a child with donated gametes should choose a donor whose identity will be made available to the resulting child. This is not, Groll argues, because having genetic knowledge is fundamentally important. Rather, it is because donor-conceived people are likely to develop a significant interest in having genetic knowledge and parents must help satisfy their children's significant interests. In other words, because a donor-conceived person is likely to care about having genetic knowledge, their parents should care too. (shrink)

In this paper, we argue that ‘Weak Modal Rationalism’, which is the view that ideal primary positive conceivability entails primary metaphysical possibility, is self-defeating. To this end, we outline two reductio arguments against ‘Weak Modal Rationalism’. The first reductio shows that, from supposing that ‘Weak Modal Rationalism’ is true, it follows that conceivability both is and is not conclusive evidence for possibility. The second reductio shows that, from supposing that ‘Weak Modal Rationalism’ is true, it follows that it (...) is possible that ‘Weak Modal Rationalism’ is necessarily false, and hence that ‘Weak Modal Rationalism’ is false. We then argue that adopting a weaker position according to which conceivability is merely prima facie evidence for possibility provides limited protection from our criticism of conceivability arguments. (shrink)

This paper was chosen by The Philosopher’s Annual as one of the ten best articles appearing in print in 2000. Reprinted in Volume XXIII of The Philosopher’s Annual. In his very influential book David Chalmers argues that if physicalism is true then every positive truth is a priori entailed by the full physical description – this is called “the a priori entailment thesis – but ascriptions of phenomenal consciousness are not so entailed and he concludes that Physicalism is false. As (...) he puts it, “zombies” are metaphysically possible. I attempt to show that this argument is refuted by considering an analogous argument in the mouth of a zombie. The conclusion of this argument is false so one of the premises is false. I argue at length that this shows that the original conceivability argument also has a false premise and so is invalid. (shrink)

The paper presents a dilemma for both epistemic and non-epistemic versions of conceivability-based accounts of modal knowledge. On the one horn, non-epistemic accounts do not elucidate the essentialist knowledge they would be committed to. On the other, epistemic accounts do not elucidate everyday life de re modal knowledge. In neither case, therefore, do conceivability accounts elucidate de re modal knowledge.

I present an approach to our conceiving absolute impossibilities—things which obtain at no possible world—in terms of ceteris paribus intentional operators: variably restricted quantifiers on possible and impossible worlds based on world similarity. The explicit content of a representation plays a role similar in some respects to the one of a ceteris paribus conditional antecedent. I discuss how such operators invalidate logical closure for conceivability, and how similarity works when impossible worlds are around. Unlike what happens with ceteris paribus (...) counterfactual conditionals, the closest worlds are relevantly closest belief-worlds: closest to how things are believed to be, rather than to how they are. Also, closeness takes into account apriority and the opacity of intentional contexts. (shrink)

The conceivability argument against physicalism1 starts from the prem- ises that: It is conceivable that I have a zombie-twin, i.e., that there is someone who is physically identical to me and yet who lacks phenomenal con- sciousness; and If it is conceivable that I have a zombie-twin, then it is possible that I have a zombie-twin. These premises entail that physicalism is false, for physicalism is the claim—or can be assumed for our purposes to be the claim2—that.

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. One purpose of this paper is to argue that the notion is not fruitfully explicated in terms of the imagination. The most natural way of presenting a notion of conceivability qua imaginability is open to cogent criticism. In order to avoid such criticism, an advocate of the modal insightfulness (...) of the imagination must broaden the idea of what it is to be imaginable. I argue that this required broadening renders the imagination idle . Consequently, I distinguish two different accounts of the evidential basis of modal knowledge and present a more general argument that concludes that the very notion of conceivability should be eschewed in modal epistemology. (shrink)

This paper advances the thesis that we can justifiably believe philosophically interesting possibility statements. The first part of the paper critically discusses van Inwagens skeptical arguments while at the same time laying some of the foundation for a positive view. The second part of the paper advances a view of conceivability in terms of imaginability, where imaginging can be propositional, pictorial, or a combination of the two, and argues that conceivability can, and often does, provide us with justified (...) beliefs of what is metaphysically possible. The notion of scenarios is developed, as is an account of how filling out scenarios can uncover a defeater or, in many cases, strengthen the justification for the relevant possibility statement. (shrink)

The purpose of this article is to defend Hume's claim that whatever is conceivable is possible from a criticism by William Kneale. Kneale argues that although a mathematician can conceive of the falsehood of the Goldbach conjecture, he does not conclude that it is not necessarily true. The author suggests that by taking into account Hume's distinction between intuitive and demonstrative knowledge, a revised version of his claim can be offered which is not open to Kneale's criticism.

Materialism in the philosophy of mind is the thesis that the ultimate nature of the mind is physical; there is no sharp discontinuity in nature between the mental and the non-mental. Anti-materialists asser t that, on the contrary, mental phenomena are different in kind from physical phenomena. Among the weapons in the arsenal of anti-materialists, one of the most potent has been the conceivability argument. When I conceive of the mental, it seems utterly unlike the physical. Anti-materialists insist that (...) from this intuitive difference we can infer a genuine meta-physical difference. Materialists retor t that the nature of reality, including the ultimate natures of its constituents, is a matter for discovery; an objective fact that cannot be discerned a priori. In this paper I under take to provide an explicit analysis of the dialectic that surrounds the conceivability argument. My principal conclusion is that the materialist is right in resisting the reasoning that star ts from considerations of what is conceivable and ends with genuine metaphysical conclusions. However my approach is much more sympathetic to the anti-materialist position than is the standard materialist line, and I will provide a limited defense of some crucial aspects of the anti-materialist position. Materialism will emerge from this fight intact, but shaken. (shrink)

According to haecceitism, some maximal possibilities differ even while they are qualitatively indiscernible. Since haecceitism is a modal thesis, it is typically defended by appeal to conceivability arguments. These arguments require us to conceive of qualitatively indiscernible possibilities that differ only with respect to the identity of the individuals involved. This paper examines a series of conceivability arguments for haecceitism and a variety of anti-haecceitist responses. It concludes that there is no irresistible conceivability argument for haecceitism even (...) while anti-haecceitist responses do come with certain notable commitments. (shrink)

Intuitions based on the first-person perspective can easily mislead us about what is and is not conceivable.1 This point is usually made in support of familiar reductionist positions on the mind-body problem, but I believe it can be detached from that approach. It seems to me that the powerful appearance of contingency in the relation between the functioning of the physical organism and the conscious mind -- an appearance that depends directly or indirectly on the first- person perspective -- must (...) be an illusion. But the denial of this contingency should not take the form of a reductionist account of consciousness of the usual type, whereby the logical gap between the mental and the physical is closed by conceptual analysis -- in effect, by analyzing the mental in terms of the physical. (shrink)

Conceivability arguments constitute a serious threat against reductive physicalism. Recently, a number of authors have proven and characterized a devastating logical truth, centered on these arguments: namely, that their soundness entails the inconceivability of reductive physicalism. In this paper, I demonstrate that is only a logical truth when reductive physicalism is interpreted in its stronger, intrinsic sense, as opposed to its weaker—yet considerably more popular—extrinsic sense. The basic idea generalizes: perhaps surprisingly, stronger forms of reduction are uniquely resistant to (...) the conceivability arguments opposing them. So far as the modal epistemology of reduction is concerned, therefore, it pays to go intrinsic. (shrink)

In his conceivability argument, Chalmers assumes that all properties have their causal powers contingently and causal laws are also contingent. We argue that this claim conflicts with how conceivability itself must work for the conceivability argument to be successful. If conceivability is to be an effective mechanism to determine possibility, it must work as a matter of necessity, since contingent conceivability renders conceivability fallible for an ideal reasoner and the fallible conceivability of zombies (...) would not entail their possibility. But necessary conceivability must either be governed by necessitating causal processes or by a necessitating non-causal mechanism. We argue that the latter option is untenable or mysterious; whereas, if Chalmers chooses the former and applies it only to conceivability, his solution is ad hoc, but if he accepts necessary causal powers or processes generally, the conceivability argument fails. We conclude that, as it stands, the Conceivability Argument does not establish that physicalism is false. (shrink)

According to the ‘conceivability argument’ [1] it’s conceivable that a conscious human being H may have a perfect physical duplicate H* who isn’t conscious, [2] whatever is conceivable is possible, therefore [3] H* may possibly exist. This paper argues that the conceivability argument can’t help in discussion of the ‘mind–body problem’ even if [2] is allowed to be true. This is not because [1] is false, but because we don’t and can’t know enough about the nature of the (...) physical to know whether or not [1] is true. This follows from ‘the silence of physics’—the fact that physics neither does nor can tell us about the intrinsic non-structural nature of the physical, and the consequences of this fact for any adequate account of the meaning of the word ‘physical’. (shrink)

Most twenty-first century ethicists conceive of character as a stable, enduring state that is internal to the agent who possesses it. This paper argues that writers in the 17th and 18th centuries did not share this conception: as they conceived it, character is fragile and has a social ontology. The paper goes on to show that Hume’s conception of character was more like his contemporaries than like ours. It concludes with a look at the significance of such a conception for (...) current debates about the place of character in ethics. (shrink)

Some people might be tempted by modal ontological arguments from the possibility that God exists to the conclusion that God in fact exists. They might also be tempted to support the claim that possibly God exists by appealing to the conceivability of God’s existence. In this chapter, I introduce three constraints on an adequate theory of philosophical conceivability. I then consider and develop both imagination-based accounts of conceivability and conceptual coherence-based accounts of conceivability. Finally, I return (...) to the modal ontological argument and consider whether the premise that possibly God exists can be supported by some conceiving. (shrink)

David Chalmers' conceivability argument against physicalism relies on the entailment from a priori conceivability to metaphysical possibility. The a posteriori physicalist rejects this premise, but is consequently committed to psychophysical strong necessities. These don't fit into the Kripkean model of the necessary a posteriori, and they are therefore, according to Chalmers, problematic. But given semantic assumptions that are essential to the conceivability argument, there is reason to believe in microphysical strong necessities. This means that some of Chalmers' (...) criticism is unwarranted, and the rest equally afflicts the dualist. Moreover, given that these assumptions are independently plausible, there's a general case to be made for the existence of strong necessities outside the psychophysical domain. (shrink)

This essay aims to redress the contention that epistemic possibility cannot be a guide to the principles of modal metaphysics. I introduce a novel epistemic two-dimensional truthmaker semantics. I argue that the interaction between the two-dimensional framework and the mereological parthood relation enables epistemic possibilities and truthmakers to be a guide to the metaphysical profiles of the qualitative haecceitistic properties of individuals. I specify, then, a two-dimensional formula encoding the relation between the epistemic possibility and verification of haecceity comprehension and (...) its metaphysical possibility or verification. I then generalize the approach to essential properties, and examine the Julius Caesar problem as a test case. I conclude by addressing objections from the indeterminacy of ontological principles relative to the space of epistemic possibilities, and from the consistency of epistemic modal space. (shrink)

Christopher Hill contends that the metaphysical modalities can be reductively explained in terms of the subjunctive conditional and that this reductive explanation yields two tests for determining the metaphysical modality of a proposition. He goes on to argue that his reductive account of the metaphysical modalities in conjunction with his account of modal knowledge underwrites the further conclusion that conceivability does not provide a reliable test for metaphysical possibility. I argue (1) that Hill’s reductive explanation of the metaphysical modalities (...) in terms of the subjunctive conditional does not yield a reductive explanation of knowledge of metaphysical modality in terms of knowledge of subjunctive conditionals, and (2) that his account of modal knowledge is at odds with his contention that conceivability does not provide epistemic access to metaphysical possibility. (shrink)

This paper examines the ramifications of Hume's view of the relation of conceivability to metaphysical possibility. It argues that the limitations Hume places of the representations involved in moves to conceivability to metaphysical possibility preclude any straightforward argument against full-blooded causal realism in Hume from conceivability. Furthermore, our finding certain states of affairs conceivable when they are not metaphysically possible is perfectly compatible with the thrust of the causal realist position.

In The Conscious Mind, D. Chalmers appeals to his semantic framework in order to show that conceivability, as employed in his "zombie" argument for dualism , is sufficient for genuine possibility. I criticize this attempt.

Las intuiciones basadas en la perspectivade la primera persona fácilmente nospueden inducir a error sobre lo que es yno es concebible. Este punto usualmentese presenta como apoyo de posicionesreduccionistas comunes sobre el problemamente-cuerpo, pero considero que se puedeseparar de tal perspectiva. Me pareceque la fuerte apariencia de contingenciaen la relación entre el funcionamiento delorganismo físico y la mente consciente–una apariencia que depende directa oindirectamente de la perspectiva de laprimera persona– tiene que ser una ilusión.Enotraspalabras,creoquehayunaconexiónnecesariaenambasdireccionesentre lo físico y lo mental, pero (...) que nopuede descubrirse a priori. La opinión sedivide fuertemente entre la credibilidad dealgún tipo de reduccionismo funcionalista,y no examinaré mis razones para ubicarmeen el lado antireduccionista de este debate.Mi lectura del asunto es que nuestra faltade habilidad para obtener una concepcióninteligible de la relación mente-cuerpo esun signo de la inadecuación de nuestrosconceptos actuales, y que se requiere algúngrado de desarrollo.The Intuitions based on the first-personperspective can easily mislead us aboutwhat is and is not conceivable. This pointis usually made in support of familiarreductionist positions on the mind-bodyproblem, but I believe it can be detachedfrom that approach. It seems to me thatthe powerful appearance of contingency inthe relation between the functioning of thephysical organism and the conscious mind–an appearance that depends directly orindirectly on the first person– perspectivemust be an illusion. In other words, I believethatthereisanecessaryconnectioninbothdirectionsbetweenthephysicalandthemental,butthatitcannot bediscovereda priori. Opinion is strongly divided on thecredibility of some kind of functionalistreductionism, and I won’t go through myreasons for being on the antireductionistside of that debate.My reading of the situation is that ourinability to come up with an intelligibleconception of the relation between mindand body is a sign of the inadequacy of ourpresent concepts, and that some developmentis needed. (shrink)

According to Spinoza, what is the relationship between the mental – ideas, minds, and the attribute of Thought – and the conceptual – concepts, conceiving, and conceptual dependence? The natural and pervasive interpretive assumption that Spinoza’s appeals to the conceptual are synonymous with appeals to the mental ought to be rejected, a rejection that prevents some of his central metaphysical doctrines from otherwise collapsing into incoherence. A close reading of key texts shows instead that conceptual relations are attribute-neutral for Spinoza; (...) mental relations comprise a proper subset of conceptual relations. This surprising conclusion, that the conceptual outstrips the mental, also sheds new light the relationship between the attributes, the extent of parallelism, and the nature of extension. It also shows how Spinoza’s frequent privileging of the conceptual avoids collapsing into a kind of idealism, a central point on which the most novel recent interpretation of Spinoza (Michael Della Rocca’s) falters. (shrink)

This paper challenges the soundness of the two-dimensional conceivability argument against the derivation of phenomenal truths from physical truths in light of a hyperintensional, ground-theoretic regimentation of the ontology of consciousness. The regimentation demonstrates how ontological dependencies between truths about consciousness and about physics cannot be witnessed by epistemic constraints, when the latter are recorded by the conceivability—i.e., the epistemic possibility—thereof. Generalizations and other aspects of the philosophical significance of the hyperintensional regimentation are further examined.

In a recent paper, Dennis Plaisted examines an important argument that Leibniz gives for the existence of primitive concepts. After sketching a natural reading of this argument, Plaisted observes that the argument appears to imply something clearly inconsistent with Leibniz’s other views. To save Leibniz from contradiction, Plaisted offers a revision. However, his account faces a number of serious difficulties and therefore does not successfully eliminate the inconsistency. We explain these difficulties and defend a more plausible alternative. In the process, (...) we call attention to the neglected topic of Leibniz’s views on the nature of conceiving, and reveal his commitment to the somewhat surprising thesis that one can conceive something through a concept even if one has no conscious grasp of that concept. (shrink)

Wright (In Gendler and Hawthorne (Eds.), Conceivability and possibility, 2002) rejects some dominant responses to Kripke’s modal argument against the mind-body identity theory, and instead he proposes a new response that draws on a certain understanding of counterpossibles. This paper offers some defensive remarks on behalf of Lewis’ objection to that argument, and it argues that Wright’s proposal fails to fully accommodate the conceivability intuitions, and that it is dialectically ineffective.

This paper compares and contrasts two conceivability arguments: the zombie argument (ZA) against physicalism, and the perfect actor argument (AA) against behaviourism. I start the paper by assuming that the arguments are of the same kind, and that AA is sound. On the basis of these two assumptions I criticize the most common philosophical suggestions in the literature today about what is wrong with ZA, and what is right in it. I end the paper by suggesting that the comparison (...) between the two arguments makes plausible an epistemic response to ZA according to which the conceivability of a zombie - that is, someone identical to me in all physical respects but different in some phenomenal respect - is being confused with the conceivability of something else, i.e. someone identical to me in physical respects that are epistemically available, but different in some phenomenal respect. (shrink)

In contemporary philosophy of mind, the conceivability argument against physicalism is often used to support a form of dualism, which takes consciousness to be ontologically fundamental and distinct from physical matter. Recently, some proponents of the conceivability argument have also shown interest in panpsychism, which is the view that mentality is ubiquitous in the natural world. This paper examines the extent to which panpsychism can be sustained if the conceivability argument is taken seriously. I argue that panpsychism’s (...) ubiquity claim permits a strong reading or a weak reading. This presents a dilemma. On the one hand, the strong reading, which is typically characterised as a form of monism, is undermined by the conceivability argument. On the other hand, the weak reading, while compatible with the conceivability argument, turns out just to be a special case of dualism. I also show that the related position of panprotopsychism cannot provide a tenable monist position because it too cannot withstand the challenge of the conceivability argument. Therefore, if the conceivability argument is taken seriously, then we are committed to a dualist metaphysics, regardless of whether or not we accept the ubiquity claim. (shrink)

To what extent and how is conceivability a guide to possibility? This essay explores general philosophical issues raised by this question, and critically surveys responses to it by Descartes, Hume, Kripke and "two-dimensionalists.".

We propose a novel account of the distinction between innate and acquired biological traits: biological traits are innate to the degree that they are caused by factors intrinsic to the organism at the time of its origin; they are acquired to the degree that they are caused by factors extrinsic to the organism. This account borrows from recent work on causation in order to make rigorous the notion of quantitative contributions to traits by different factors in development. We avoid the (...) pitfalls of previous accounts and argue that the distinction between innate and acquired traits is scientifically useful. We therefore address not only previous accounts of innateness but also skeptics about any account. The two are linked, in that a better account of innateness also enables us better to address the skeptics. (shrink)

Why is there a felt asymmetry between cases in which agents defer to testifiers for certain moral beliefs, and cases in which agents defer on many other matters? One explanation influential in the literature is that having understanding of a proposition is both in tension with acquiring belief in the proposition by deferring to another's testimony and distinctively important when it comes to moral propositions, as compared with what we might think of as many ‘garden variety’ facts. My project in (...) this paper is to offer a new and more defensible version of this explanation. This will involve re-conceiving understanding as a richer state than it is commonly thought to be, requiring affective and motivational engagement with reasons as well as cognitive facility. I also offer a new explanation of the tension between understanding and deference to testimony. (shrink)

In this paper I argue that certain so-called conceivability arguments fail to show that a currently popular version of physicalism in the philosophy of mind is false. Concentrating on an argument due to David Chalmers, I first argue that Chalmers misrepresents the relation between conceivability and possibility. I then argue that the intuition behind the conceivability of so-called zombie worlds can be accounted for without having to suppose that such worlds are genuinely conceivable. I conclude with some (...) general remarks about the nature of conceivability. (shrink)

In the history of modern philosophy systematic connections were assumed to hold between the modal concepts of logical possibility and necessity and the concept of conceivability. However, in the eyes of many contemporary philosophers, insuperable objections face any attempt to analyze the modal concepts in terms of conceivability. It is important to keep in mind that a philosophical explanation of modality does not have to take the form of a reductive analysis. In this paper I attempt to provide (...) a response-dependent account of the modal concepts in terms of conceivability along the lines of a nonreductive model of explanation. (shrink)

In his 1998 postscript to ‘The Possibility of Resurrection’ Peter van Inwagen argues that the scenario he describes by which God might resurrect a human organism, even though probably not true, is still conceivable and, consequently, ‘serves to establish a possibility’, namely, the metaphysical possibility of the resurrection of material beings. Van Inwagen, however, has also argued in favour of ‘modal scepticism’ [van Inwagen in, God, knowledge and mystery: essays in philosophical theology, Cornell University Press, Ithaca 1995b, pp. 11–12; van (...) Inwagen in, Philos Stud 92:67–84, 1998a]. That is, he thinks that we should limit all our claims about what is possible to ‘ordinary propositions about everyday matters’, 1998a). In this paper I argue that van Inwagen’s modal argument as found in ‘The Possibility of Resurrection’ is inconsistent with his modal scepticism as found in ‘Modal Epistemology’. In consequence, I argue that, given his modal scepticism, the task van Inwagen set himself in ‘The Possibility of Resurrection’ has not been achieved. (shrink)