Is the world internally connected by a web of necessary connections or is everything loose and independent? Followers of David Hume accept the latter by upholding Hume’s Dictum, according to which there are no necessary connections between distinct existences. Roughly put, anything can coexist with anything else, and anything can fail to coexist with anything else. Hume put it like this: “There is no object which implies the existence of any other if we consider these objects in themselves.” Since Hume’s (...) day, Hume’s Dictum has played a major role in philosophy, especially in contemporary metaphysics. In ruling out necessary connections, Hume’s Dictum implies that causal relations and the laws of nature are contingent. It makes other demands on our metaphysics of science as well; for example, it places restrictions on our metaphysics of counterfactuals, dispositions, and explanation. The principle has applications in other areas too. Hume’s Dictum places constraints on our theories of abstract objects and moral properties. For example, Hume’s Dictum rules out the view that moral properties are distinct from, but necessarily connected to, non-moral properties. While Hume’s Dictum is a prominent principle in metaphysics, few Humeans have defended the principle at length. It is assumed more often than it is argued for. As a result, Hume’s Dictum no longer enjoys the reputation it once did. It’s common to hear complaints about the lack of arguments in support of Hume’s Dictum. Moreover, philosophers are increasingly willing to defend views that are at odds with Hume’s Dictum. A striking example of this is the recent explosion of interest in views that take causal relations and the laws of nature to be necessary. Humeans can no longer afford to be complacent. An extended defense of Hume’s Dictum is called for, and that’s what this dissertation aims to offer. This dissertation has three parts. In the first part, I lay out some preliminaries and offer a precise formulation of Hume’s Dictum. In the second part, I develop three arguments in favor of Hume’s Dictum. In the final part, I defend Hume’s Dictum against objections. (shrink)

Ramseyan humility is the thesis that we cannot know which properties realize the roles specified by the laws of completed physics. Lewis seems to offer a sceptical argument for this conclusion. Humean fundamental properties can be permuted as to their causal roles and distribution throughout spacetime, yielding alternative possible worlds with the same fundamental structure as actuality, but at which the totality of available evidence is the same. On the assumption that empirical knowledge requires evidence, we cannot know which of (...) these worlds is actual. However, Lewis also appeals to a range of familiar semantic principles when framing his argument, which leads some authors to suppose that he can also plausibly be interpreted as offering a purely semantic argument for humility in addition. In this paper I grant that these arguments are Lewisian, but argue that Lewis is also committed to a theory of mind that licenses a purely metaphysical argument for humility based on the idea that mental properties supervene on fundamental structure. Given that knowing which x is the F requires knowing that a is the F, the supposition that we could come to know which properties actually occupy the fundamental roles entails differences in mental properties between worlds with the same fundamental structure, violating supervenience. Humility follows right away, without any further epistemic or semantic principles. This argument is immune to almost every way of rebutting the sceptical and semantic arguments; conversely, almost every way of rebutting the metaphysical argument tells equally against the others. (shrink)

Considerations upon the nature of properties and laws have led some philosophers to claim that the correct epistemic attitude with regards to the intrinsic properties of particulars is scepticism. I examine one particularly clear version of this line of argument, and contend that a serious form of scepticism is not established. However, I argue that the theories of properties and laws underlying the argument have unwanted metaphysical implications. These provide a stronger reason to jettison the analyses. I end by sketching (...) an alternative view that avoids these difficulties. -/- . (shrink)

Notoriously, the dispositional view of natural properties is thought to face a number of regress problems, one of which points to an epistemological worry. In this paper, I argue that the rival categorical view is also susceptible to the same kind of regress problem. This problem can be overcome, most plausibly, with the development of a structuralist epistemology. After identifying problems faced by alternative solutions, I sketch the main features of this structuralist epistemological approach, referring to graph-theoretic modelling in the (...) process. Given that both the categoricalists and dispositionalists are under pressure to adopt this same epistemological approach in light of the regress problem, this suggests that the categoricalist versus dispositionalist debate is best fought on metaphysical rather than epistemological grounds. (shrink)

Over the last decade or so, there has been a renewed interest in a view about properties known as quidditism. However, a review of the literature reveals that ‘quidditism’ is used to cover a range of distinct views. In this paper I explore the logical space of distinct types of quidditism. The first distinction noted is between quidditism as a thesis explicitly about property individuation and quidditism as a principle of unrestricted property recombination. The distinction recently drawn by Dustin Locke (...) between extravagant quidditism and austere quidditism is a distinction between quidditisms of the first type. It is then argued that austere quidditism may itself be further sub-divided into what I call ‘extremely austere quidditism’ and ‘moderately austere quidditism’. Moderately austere quidditism is argued to be preferable to extremely austere quidditism and further to be able to address many of the arguments leveled against quidditism in general. (shrink)

Robert Black argues against quidditism on the grounds that the quidditist is either committed to proper-class many possible worlds and proper-class many possible fundamental properties or must adopt an unacceptably arbitrary restriction on the number of possible fundamental properties. In this paper, I examine Black’s cardinality argument against quidditism and argue that quidditists and non-quidditists alike have reason to reject a key premise of that argument. While it may be the case that the quidditist is committed to nomically indiscernible possible (...) worlds that mark distinctions that make no difference to the physicist, it does not appear that the cardinality of the class of possible worlds or the class of possible fundamental properties postulated by the quidditist is any more problematic than that postulated by the non-quidditist. (shrink)

The article discusses John Foster’s last attempt at refutation of physical realism and defence of phenomenalistic idealism. Main Foster’s arguments against physical realism, the argument from «the problem of perception» and the argument from the inscrutability of intrinsic content of the external reality are scrutinized and found wanting. The argument from «the problem of perception» is shown to fail against «the decompositional view» because it falsely assumes that the perception of an object, if it is mediated by some processes and (...) states, requires the perception of those mediating processes and states. The argument from the inscrutability of intrinsic content is found unsuccessful because physical realism can accommodate Kantian agnosticism about intrinsic contents, while holding that physical reality is knowable in all structural and dynamical respects that in fact constitute the realm of study of natural sciences. Foster’s further argument that involves the spatial swap scenario is shown to beg the question: a physical realist can plausibly and arguably deny either the logical possibility of such a scenario, or Foster’s idealism-favouring construal of it. On the other hand, it is pointed out that Foster’s treatment of the timing of the prehuman history of the Universe is gravely unsatisfactory and suggests the refutation of phenomenalistic idealism. (shrink)

In this article, I discuss Richard Swinburne’s case for the conception of substance causation, identified with the substances-powers-liabilities account of causation, versus the conception of event causation, identified with alternative accounts. I specify the place of Swinburne’s argument in the debates about agent causation, and uncover reasons to be sceptical about the claims that substance causation is a genuine alternative to event causation, and that it helps to comprehend the specifics of the causation involved in free agency. I also advance (...) considerations in favour of the relations-between-universals account of causation that can make it preferable to the SPL account. (shrink)

that the properties of science are purely extrinsic with the metaphysical principle that substances must also have intrinsic properties, the arguments reach the conclusion that there are intrinsic properties of whose natures we cannot know. It is the goal of this paper to establish that such arguments are not just ironic but extremely problematic. The optimistic physicalist principles that help get the argument off the ground ultimately undermine any justification the premises give for acceptance of the conclusion. Though I do (...) find these arguments unsound, it is nevertheless worthwhile to consider them in order to see more clearly what should be the methodology of the philosopher inclined to take the discoveries of physical science as having ontological authority. And, I hope, what follows will prompt the physicalist to ask herself – what room _is_ there for metaphysics once physical science is complete? (shrink)

David Lewis argues for Ramseyan humility, the thesis that we can’t identify the fundamental properties that occupy the nomological roles at our world. Lewis, however, remarks that there is a potential exception to this, which involves assuming two views concerning qualia panphenomenalism : all instantiated fundamental properties are qualia and the identification thesis : we can know the identities of our qualia simply by being acquainted with them. This paper aims to provide an exposition, as well as an assessment, of (...) this response to the humility thesis. (shrink)

Structuralism and quidditism are competing views of the metaphysics of property individuation: structuralists claim that properties are individuated by their nomological roles; quidditists claim that they are individuated by something else. This paper (1) refutes what many see as the best reason to accept structuralism over quidditism and (2) offers a methodological argument in favor of a quidditism. The standard charge against quidditism is that it commits us to something ontologically otiose: intrinsic aspects of properties, so-called ‘quiddities’. Here I grant (...) that quiddities are ontologically otiose, but deny that quidditism requires them. According to a view I call ‘austere quidditism’, properties are individuated by bare numerical identity. I argue that, as far as ontological parsimony is concerned, austere quidditism and structuralism are on a par. But is austere quidditism a coherent alternative to structuralism? To see that it is, we must get clear on what exactly we mean by ‘property individuation’. What we discover is that structuralism is a counterpart theory for properties, and that austere quidditism is simply the rejection of counterpart theory. I conclude with a methodological argument to the effect that counterpart theory for properties ought to be rejected. This paper begins by situating the debate between structuralists and quidditists within the context of a debate over the epistemic limits of fundamental science. At the center of this debate is David Lewis’s posthumously published ‘Ramseyan Humility’ (2008). In the appendix I explain the precise role of austere quidditism in Lewis’s argument. (shrink)

In "Ramseyan Humility," David Lewis argues that we cannot know what the fundamental properties in our world are. His arguments invoke the possibility of permutations and replacements of fundamental properties. Most responses focus on Lewis’s view on the relationship between properties and roles, and on the assumptions about knowledge that he makes. I argue that no matter how the debates about knowledge and about the metaphysics of properties turn out, Lewis’s arguments are unconvincing since they rely on a highly implausible (...) assumption about the expressive power of our language. (shrink)

Kant’s claim that we are ignorant of things in themselves is a claim that we cannot know ‘the intrinsic nature of things’, or so at least I argued in Kantian Humility.2 I’m delighted to find that Lucy Allais is in broad agreement with this core idea, thinking it represents, at the very least, a part of Kant’s view. She sees some of the advantages of this interpretation. It has significant textual support. It does justice to Kant’s sense that we are (...) missing out on something, in our failure to know things as they are in themselves. And it makes tellable, after all, Kant’s at first sight untellable tale, about the knowable existence of unknowable things: for we can know that things exist, without knowing what their intrinsic properties are. However, Allais is critical of the way I fill out this core idea, and she has an alternative to offer. She thinks Kant’s distinction between things in themselves and phenomena is not a distinction between two kinds of properties, intrinsic and relational. She is critical of my interpretation of causal powers, which I take to be the relevant relational properties: my idea, first, that causal powers are in fact relational properties; second, that causal powers are only contingently associated with intrinsic properties, so that creating substances with intrinsic properties is insufficient for creating causal power; and, third, that intrinsic properties are causally inert. Her criticisms of these three ideas.. (shrink)

The question of the role of theory in the determination of reference of theoretical terms continues to be a controversial one. In the present paper I assess a number of responses to this question (including variations on David Lewis’s appeal to Ramsification), before describing an alternative, epistemically oriented account of the reference-determination of such terms. The paper concludes by discussing some implications of the account for our understanding of both realism and such competitors of realism as constructive empiricism.

In ‘Ramseyan Humility’ David Lewis argues that a particular view about fundamental properties, quidditism, leads to the position that we are irredeemably ignorant of the identities of fundamental properties. We are ignorant of the identities of fundamental properties since we can never know which properties play which causal roles, and we have no other way of identifying fundamental properties other than by the causal roles they play. It has been suggested in the philosophical literature that Lewis’ argument for Humility is (...) merely an instance of traditional scepticism, to which traditional responses to scepticism are applicable. I agree that in ‘Ramseyan Humility’ Lewis does present an argument to which it is appropriate to consider the applicability of responses to traditional scepticism—he argues that we irredeemably lack the evidence to rule out possibilities in which different properties occupy the causal roles described by our best physical theory. And prima facie this is just the kind of argument responses to traditional scepticism are designed to tackle. However, I will argue that Lewis bolsters this argument with a second. This second argument serves to deepen Lewis’ case and cannot be met with a response to traditional scepticism. For Lewis argues that not only do we lack evidence for which properties play which roles, we lack the ability to grasp any such proposition about role-occupancy. And if we cannot grasp any such proposition we cannot know it. (shrink)

According to structuralism, all natural properties are individuated by their roles in causal/nomological structures. According to quidditism, at least some natural properties are individuated in some other way. Because these theses deal with the identities of natural properties, this distinction cuts to the core of a serious metaphysical dispute: Are the intrinsic natures of all natural properties essentially causal/nomological in character? I'll argue that the answer is ‘no’, or at least that this answer is more plausible than many critics of (...) quidditism have recognized. In section 1, I distinguish between two versions of quidditism. Bare quidditism holds that worlds with distinct properties and isomorphic structures must be qualitatively identical in the following sense: inhabiting one world would be indistinguishable from inhabiting the other. In contrast, qualitative quidditism allows such worlds to have qualitative differences. In section 2, I discuss an epistemological position that allows us to bett... (shrink)

According to dispositionalism, fundamental properties are dispositions—powers that don’t reduce to other properties, laws, or anything else. As dispositions manifest, natural regularities result, so this view appears to explain the uniformity of nature. However, in this paper I’ll argue that there are types of regularities that can’t be explained by dispositionalism. The basic idea is this. All accounts of fundamental dispositions endow properties with a certain sort of structure. This allows explanations of only those regularities that align with such structures. (...) In this paper, I identify a type of natural regularity that cannot fit dispositionalist structures and show why the possibility of such regularities is problematic. (shrink)

This paper has two main aims. The first is to present a general approach for understanding “dispositional” and “categorical” properties; the second aim is to use this approach to criticize Russellian Monism. On the approach I suggest, what are usually thought of as “dispositional” and “categorical” properties are really just the extreme ends of a spectrum of options. The approach allows for a number of options between these extremes, and it is plausible, I suggest, that just about everything of scientific (...) interest falls in this middle ground. I argue that Russellian Monism depends for its plausibility on the unarticulated assumption that there are no properties in the middle ground. (shrink)

The paper argues that digital ontology (the ultimate nature of reality is digital, and the universe is a computational system equivalent to a Turing Machine) should be carefully distinguished from informational ontology (the ultimate nature of reality is structural), in order to abandon the former and retain only the latter as a promising line of research. Digital vs. analogue is a Boolean dichotomy typical of our computational paradigm, but digital and analogue are only “modes of presentation” of Being (to paraphrase (...) Kant), that is, ways in which reality is experienced or conceptualised by an epistemic agent at a given level of abstraction. A preferable alternative is provided by an informational approach to structural realism, according to which knowledge of the world is knowledge of its structures. The most reasonable ontological commitment turns out to be in favour of an interpretation of reality as the totality of structures dynamically interacting with each other. The paper is the first part (the pars destruens) of a two-part piece of research. The pars construens, entitled “A Defence of Informational Structural Realism”, is developed in a separate article, also published in this journal. (shrink)

This is the revised version of an invited keynote lecture delivered at the "1st Australian Computing and Philosophy Conference". The paper is divided into two parts. The first part defends an informational approach to structural realism. It does so in three steps. First, it is shown that, within the debate about structural realism, epistemic and ontic structural realism are reconcilable. It follows that a version of OSR is defensible from a structuralist-friendly position. Second, it is argued that a version of (...) OSR is also plausible, because not all relata are logically prior to relations. Third, it is shown that a version of OSR is also applicable to both sub-observable and observable entities, by developing its ontology of structural objects in terms of informational objects. The outcome is informational structural realism, a version of OSR supporting the ontological commitment to a view of the world as the totality of informational objects dynamically interacting with each other. The paper has been discussed by several colleagues and, in the second half, ten objections that have been moved to the proposal are answered in order to clarify it further. (shrink)

Sometimes, ignorance is inexpressible. Lewis recognized this when he argued, in “Ramseyan Humility,” that we cannot know which property occupies which causal role. This peculiar state of ignorance arises in a number of other domains too, including ignorance about our position in space and the identities of individuals. In these cases, one does not know something, and yet one cannot give voice to one's ignorance in a certain way. But what does the ignorance in these cases consist in? This essay (...) argues that many standard models of ignorance cannot account for the phenomenon of inexpressible ignorance. It then develops an alternative model that does better, on which the ignorance consists in a failure to identify something by way of its nature or essence. (shrink)

My first goal is to motivate a distinctively metaphysical approach to the problem of induction. I argue that there is a precise sense in which the only way that orthodox Humean and non-Humean views can justify induction is by appealing to extremely strong and unmotivated probabilistic biases. My second goal is to sketch what such a metaphysical approach could possibly look like. After sketching such an approach, I consider a toy case that illustrates the way in which such a metaphysics (...) can help us make progress on the problem of induction. (shrink)

What is the relationship between objects and properties? According to a standard view, there are primitive individuals that ‘instantiate’ or ‘have’ various properties. According to a rival view, objects are mere ‘bundles’ of properties. While there are a number of reasons to be skeptical of primitive individuals, there are also a number of challenges that the bundle theorist faces. The goal of this paper is to formulate a view about the relationship between objects and properties that avoids many of the (...) problems inherent in both of these views. The view I will end up defending implies a particularly radical version of Monism, and it collapses the object-property distinction altogether. (shrink)

How should we account for the extraordinary regularity in the world? Humeans and Non-Humeans sharply disagree. According to Non-Humeans, the world behaves in an extraordinarily regular way because of certain necessary connections in nature. However, Humeans have thought that Non-Humean views are metaphysically objectionable. In particular, there are two general metaphysical principles that Humeans have found attractive that are incompatible with all existing versions of Non-Humeanism. My goal in this paper is to develop a novel version of Non-Humeanism that is (...) consistent with (and even entails) both of these general metaphysical principles. By endorsing such a view, one can have the explanatory benefits of Non-Humeanism while at the same time avoiding two of the major metaphysical objections towards Non-Humeanism. (shrink)

The current conception of the plurality of worlds is founded on a set theoretic understanding of possibilia. This paper provides an alternative category theoretic conception and argues that it is at least as serviceable for our understanding of possibilia. In addition to or instead of the notion of possibilia conceived as possible objects or possible individuals, this alternative to set theoretic modal realism requires the notion of possible morphisms, conceived as possible changes, processes or transformations. To support this alternative conception (...) of the plurality of worlds, I provide two examples where a category theoretic account can do work traditionally done by the set theoretic account: one on modal logic and another on paradoxes of size. I argue that the categorial account works at least as well as the set theoretic account, and moreover suggest that it has something to add in each case: it makes apparent avenues of inquiry that were obscured, if not invisible, on the set theoretic account. I conclude with a plea for epistemological humility about our acceptance of either a category-like or set-like realist ontology of modality. (shrink)

Some questions are posed for van Fraassen, concerning the role and status of metaphysics in his Scientific Representation.

When an object looks red to an observer, the visual experience of the observer has two important features. The experience visually represents the object as having a property—being red. And the experience has a phenomenological character; that is, there is something that it is like to have an experience of seeing an object as red. Let qualia be the properties that give our sensory and perceptual experiences their phenomenological character. This essay takes up two related problem for a nonreductive account (...) of qualia. Some have argued that on such an account there is no room in a physicalist ontology for qualia. Section 1 shows how qualia might fit into a physicalist ontology. The second problem begins with the observation that there is a gap in scientific accounts of color experience; there is no explanation of why the features of the brain that determine our color experiences give those experiences their phenomenological character. Building on the results of Sect. 1, Sect. 2 develops an account of color perception that bridges this gap and shows how qualia give color perception its phenomenological character. To get a grip on the issues involved the paper begins by considering some aspects of a physicalist account of color. (shrink)

The Humility Thesis is a persistent thesis in contemporary metaphysics. It is known by a variety of names, including, but not limited to, Humility, Intrinsic Humility, Kantian Humility, Kantian Physicalism, Intrinsic Ignorance, Categorical Ignorance, Irremediable Ignorance, and Noumenalism. According to the thesis, we human beings, and any knowers that share our general ways of knowing, are irremediably ignorant of a certain class of properties that are intrinsic to material entities … Continue reading Humility Regarding Intrinsic Properties →.

The glass vase on my desk is fragile. It should be handled with care because it it is likely to shatter or crack if it is knocked, dropped, or otherwise treated roughly. The vase has certain dispositions, for example the disposition to shatter when dropped. But what is this disposition? It seems on the one hand to be a perfectly real property, a genuine respect of similarity common to glass vases, china cups, ancient manuscripts, and anything else fragile. Yet on (...) the other hand my vase's disposition seems mysterious, "ethereal" (as Nelson Goodman (1954) put it) in a way that, say, its size and shape properties are not. For my vase's disposition, it seems, has to do only with its possibly shattering in certain conditions, conditions which I hope will never be realized. In general, it seems that nothing about the actual behavior of an object is ever necessary for it to have the dispositions it has. Many objects differ from each other with respect to their dispositions in virtue of their merely possible behavior, and this is a mysterious way for objects to differ. (shrink)

This thesis introduces the Problem of Consciousness as an antinomy between Physicalism and Primitivism about the phenomenal. I argue that Primitivism is implausible, but is supported by two conceptual gaps. The ‘–tivity gap’ holds that physical states are objective and phenomenal states are subjective, and that there is no entailment from the objective to the subjective. The ‘–trinsicality gap’ holds that physical properties are extrinsic and phenomenal qualities are intrinsic, and that there is no entailment from the extrinsic to the (...) intrinsic. Stoljar’s Epistemic View (EV) suggests that we have a limited conception of the physical world, and that the apparent inexplicability of consciousness is merely a symptom of our ignorance. I argue that EV must satisfy two conditions which require it to specify the content of our ignorance. EV’s best hope is a Russellian appeal to our ignorance of intrinsic physical properties. After arguing in favour of this ignorance claim, I show how it undermines the –trinsicality gap. However, I suggest that the –tivity gap cannot be dealt with by the Russellian ignorance hypothesis, nor by any other version of EV. However, I then argue that the Russellian ignorance hypothesis can still be deployed as half of a hybrid account of the phenomenal. Representationalist theories of consciousness have difficulty with the –trinsicality gap, but show promise with the –tivity gap. Specifically, Kriegel’s Self-Representationalism indicates that there can indeed be an entailment from objective physical states to subjective phenomenal states. This paves the way for my hybrid account of consciousness: the subjectivity of a phenomenal state is the product of its self-representational structure, and the qualitative character of a phenomenal state is the product of the epistemically inaccessible intrinsic physical properties involved in its implementation. (shrink)

The Identity of Indiscernibles is the principle that objects cannot differ only numerically. It is widely held that one interpretation of this principle is trivially true: the claim that objects that bear all of the same properties are identical. This triviality ostensibly arises from haecceities (properties like \textit{is identical to a}). I argue that this is not the case; we do not trivialize the Identity of Indiscernibles with haecceities, because it is impossible to express the haecceities of indiscernible objects. I (...) then argue that this inexpressibility generalizes to all of their trivializing properties. Whether the Identity of Indiscernibles is trivially true ultimately turns on whether we can quantify over properties that we cannot express. (shrink)

Starting from the sixties of the past century theory change has become a main concern of philosophy of science. Two of the best known formal accounts of theory change are the post-Popperian theories of verisimilitude (PPV for short) and the AGM theory of belief change (AGM for short). In this paper, we will investigate the conceptual relations between PPV and AGM and, in particular, we will ask whether the AGM rules for theory change are effective means for approaching the truth, (...) i.e., for achieving the cognitive aim of science pointed out by PPV. First, the key ideas of PPV and AGM and their application to a particular kind of propositional theories - the so called "conjunctive propositions" - will be illustrated. Afterwards, we will prove that, as far as conjunctive propositions are concerned, AGM belief change is an effective tool for approaching the truth. (shrink)

This thesis concerns the relation between the fundamental properties and the powers they confer. The views considered are introduced in terms of their acceptance or rejection of the quiddistic thesis. Essentially the quiddistic thesis claims that properties confer the powers they do neither necessarily nor sufficiently. Quidditism is the view that accepts the quiddistic thesis. The other two views to be considered, the pure powers view and the grounded view reject the quiddistic thesis. The pure powers view supports its denial (...) of the quiddistic thesis with the claim that properties consist in conferring the powers they do; the possession of a property just is the possession of a power. The grounded view, the positive view of this thesis, rejects the idea that properties are constituted by conferring the causal powers they do. Rather on the grounded view, it is the natures of the fundamental properties that metaphysically explain why they confer the powers they do. (shrink)