Jason Brennan and Peter Jaworski argue in recent work that “semiotic” or “symbolic” objections to markets are unsuccessful. I counter-argue that there are indeed some semiotic limits on markets and that anti-commodification theorists are not merely expressing disgust when they disapprove of markets in certain goods on those grounds. One central argument is that, contrary to what Brennan and Jaworski claim, semiotic arguments against markets do not depend fundamentally on meanings that prevail about markets. Rather, they depend on the meanings (...) that attach to various goods, meanings that give us moral bases on which to make judgments about their prospective commodification. (shrink)

This paper argues that an individualist perspective is a crucial element of William James’s metaphilosophical outlook. In broad outline, the individualist argument the paper attributes to James can be characterized like this. Disputes among philosophers about the optimal point of view from which to consider this or that philosophical problem are themselves only adequately adjudicated from an individualist perspective. That is, when it comes to an assortment of important philosophical questions (not all of them perhaps, but a significant number), an (...) individualist perspective should replace a more objective one, and whether it should or not is itself a question that should be decided from an individualist perspective. (shrink)

This paper revisits some of the arguments in Richard Rorty’s Achieving Our Country, twenty years after the book first appeared. Not only are many of Rorty’s diagnoses and predictions eerily prescient in the wake of the rise of Donald Trump to the US presidency, but there is also perceptive political advice in Rorty’s book that I argue the contemporary American Left would do well to heed. While many post-election commentators have tended to read Achieving Our Country as an admonishment of (...) so-called “identity politics” in favor of an “old Left” politics of redistribution and economic justice, I argue that the main distinction on which the analysis in Achieving Our Country hangs is between what Rorty calls “real politics” and “cultural politics”, a conclusion that is confirmed, I argue, by examining the three concrete suggestions for the American Left that together form the core positive argument in Rorty’s book. (shrink)

This critical notice provides an overview of Harry Frankfurt’s On Inequality and assesses whether Frankfurt is right to argue that equality is merely formal and empty. I counter-argue that egalitarianism, properly tweaked and circumscribed, can be defended against Frankfurt’s repudiation. After surveying the main arguments in Frankfurt’s book, I argue that whatever plausibility the ‘doctrine of sufficiency’ defended by Frankfurt may have, it does not strike a fatal blow against egalitarianism. There is nothing in egalitarianism that forbids acceptance of the (...) moral platitude expressed in sufficientarianism's positive thesis,. Nor is there anything in egalitarianism as such that makes it impossible to recognize the banal truth that there are many important things besides equality, and that many dimensions of human affairs are improperly appraised from a relational or comparative point of view. The fact that a relational or comparative point o... (shrink)

Abstract:This article raises a series of doubts about Chris Voparil’s reading of Rorty, particularly the claim that what he calls “Rorty’s Pragmatic Maxim” represents what is at the heart of his philosophical vision. Those doubts are tied together with some scattered thoughts about how Voparil describes the affinities between Rorty and William James in chapter 2 of Reconstructing Pragmatism. Voparil is correct to claim that it is James, more than any other figure in the pragmatist tradition, who shares the most (...) with Rorty in “basic philosophical orientation”. Yet I also argue that Voparil fails to correctly puts his finger on what that “basic philosophical orientation” really comes to, due in large part to an excessively political reading of James and Rorty that he relies on. (shrink)

I have spent 40 years looking for a coherent and convincing way of formulating my worries about what, if anything, philosophy is good for. Richard Rorty had an unusually avid interest in metaphilosophy. Again and again he would return to questions about the practical uses (if any) to which philosophy might be put, about philosophy's role in intellectual culture, about what philosophy is or might become. His answers to these questions were famously negative: philosophy's practical uses are few, its cultural (...) role marginal. Philosophy is or will be whatever we make of it. Yet it is one thing to have given up on the idea of Philosophy as a Fach with a naturally occurring canon of problems, or in terms of the closely .. (shrink)

Interview with Kai Nielsen conducted by David Rondel and Alex Sager.

In this article I argue for two closely related conclusions: one concerned more narrowly with the internal consistency of G. A. Cohen's theorizing about justice and the unique rhetoric in which it is couched, the other connected to a more sweeping set of recommendations about how theorizing on justice is most promisingly undertaken. First, drawing on a famous insight of G. E. Moore, I argue that although the purity of Cohenian justice provides Cohen a platform from which to put some (...) extremely challenging criticisms to Rawls and Rawlsian liberals, at the same time it generates a sort of self-referential paradox for many of the theses about the concept of justice to which Cohen himself is committed. I go on to conclude, using Rawls's theory of justice as a model, that it would serve political philosophy well to conceive of justice with less purity than Cohen conceives of it. (shrink)

In this article, I argue that G. A. Cohen’s defense of the feminist slogan, “The personal is political”, his argument against Rawls’s restriction of principles of justice to the basic structure of society, depends for its intelligibility on the ability to distinguish—with reasonable but perhaps not perfect precision—between those situations in which what Nancy Rosenblum has called “the logic of congruence” is validly invoked and those in which it is not. More importantly, I suggest that the philosophical shape of Cohen’s (...) critique makes it difficult for him to supply the required criterion, and that the methodological “intuitionism” he claims to be committed to is at odds with his larger argument against Rawls concerning the subject of justice. (shrink)

In this article, I reply to some criticisms of my book, Pragmatist Egalitarianism, offered by professors Robert Talisse, Susan Dieleman, and Alexander Livingston. Some of the major themes and questions I address include the following: How are conflicts between different egalitarian ideals best understood and addressed? Does the quest for equality have a fundamental locus, or are the different egalitarian variables I identify in the book, conceptually speaking, on an equal footing? What is the relationship between justice and equality? How (...) are feminist egalitarianism and Marxian egalitarianism best slotted into my distinction between “vertical” and “horizontal” egalitarianism? What does liberalism, problematic though it may sometimes be, have to contribute to the egalitarian project? (shrink)

ABSTRACT: I argue that Joseph Raz’s service conception of authority cannot convincingly account for the nature and source of democratic authority. It cannot explain why decisions made democratically are more likely to be sound than decisions made non-democratically, and therefore, why democratic decisions might be understood as constituting moral reasons for action and compliance independently of their instrumental dimensions. My argument is that democratic authority cannot be explained completely in terms of the truth or soundness of the outcomes it tends (...) toward. A full account of democratic authority must involve non-instrumental values about the moral caliber of democratic procedures. (shrink)

This paper critically examines Richard Rorty’s “justice as larger loyalty” proposal. While Rorty is right, I argue, to reject the Kantian idea of a strict bifurcation between justice and loyalty, the former corresponding to reason the latter corresponding to sentiment, my argument is that it is nevertheless a mistake to follow Rorty in conceiving of justice as he recommends we should. This is not an endorsement of the rationalistic Kantian view Rorty rejects. Rather, I argue that there are compelling Rortyan (...) reasons for rejecting the “justice as larger loyalty” proposal, and that the argument against that proposal is paradoxically very much in the spirit of Rorty’s moral and political thought. (shrink)

An overview of Kai Nielsen's philosophy focusing on his contributions to metaphilosophy and a critical theory based on wide reflective equilibrium, global justice, and egalitarianism.

In this paper I describe how Kant’s idea about the impossibility of moral luck has come to influence, via Rawls, recent writings in egalitarian theory. I argue that this influence has been detrimental for the study of equality. Further, I claim that the major deficiencies of this post-Rawlsian egalitarianism (nicely described by Elizabeth Anderson’s title “luck egalitarianism) are both effectively critiqued and corrected by the understanding of equality and its value located in John Dewey’s writings.

"The Moral Psychology of Anxiety brings a variety of disciplinary perspectives to examine anxiety, providing historical context and incorporating recent advances in philosophical and psychological research on anxiety's nature, causes, and consequences and on its possible benefits, virtuous aspects, and role in human inquiry"--.

The Continuing Relevance of John Dewey: Reflections on Aesthetics, Morality, Science, and Society.

Lipsey and Lancaster's "general theory of second best" is widely thought to have significant implications for applied theorizing about the institutions and policies that most effectively implement abstract normative principles. It is also widely thought to have little significance for theorizing about which abstract normative principles we ought to implement. Contrary to this conventional wisdom, I show how the second-best theorem can be extended to myriad domains beyond applied normative theorizing, and in particular to more abstract theorizing about the normative (...) principles we should aim to implement. I start by separating the mathematical model used to prove the second-best theorem from its familiar economic interpretation. I then develop an alternative normative-theoretic interpretation of the model, which yields a novel second best theorem for idealistic normative theory. My method for developing this interpretation provides a template for developing additional interpretations that can extend the reach of the second-best theorem beyond normative theoretical domains. I also show how, within any domain, the implications of the second-best theorem are more specific than is typically thought. I conclude with some brief remarks on the value of mathematical models for conceptual exploration. (shrink)

Artificial intelligence has historically been conceptualized in anthropomorphic terms. Some algorithms deploy biomimetic designs in a deliberate attempt to effect a sort of digital isomorphism of the human brain. Others leverage more general learning strategies that happen to coincide with popular theories of cognitive science and social epistemology. In this paper, I challenge the anthropomorphic credentials of the neural network algorithm, whose similarities to human cognition I argue are vastly overstated and narrowly construed. I submit that three alternative supervised learning (...) methods—namely lasso penalties, bagging, and boosting—offer subtler, more interesting analogies to human reasoning as both an individual and a social phenomenon. Despite the temptation to fall back on anthropomorphic tropes when discussing AI, however, I conclude that such rhetoric is at best misleading and at worst downright dangerous. The impulse to humanize algorithms is an obstacle to properly conceptualizing the ethical challenges posed by emerging technologies. (shrink)

Why study notations, diagrams, or more broadly the variety of nonverbal “representations” or “signs” that are used in mathematical practice? This chapter maps out recent work on the topic by distinguishing three main philosophical motivations for doing so. First, some work (like that on diagrammatic reasoning) studies signs to recover norms of informal or historical mathematical practices that would get lost if the particular signs that these practices rely on were translated away; work in this vein has the potential to (...) broaden our view of the specific normativity of mathematics beyond logical proof. Second, some work focuses on signs to highlight the open-ended and “nonrigorous” aspects of mathematical practice, and the role of these aspects in the historical development of mathematics. The third motivation is based on the following observation: the reason differences in signs matter in mathematics is that humans are finite agents, with cognitive and computational limitations. Accordingly, studying signs can be a way to study how human computational constraints shape the mathematics that we do, and to tackle the topic of mathematical understanding. (shrink)

According to dispositionalism about modality, a proposition <p> is possible just in case something has, or some things have, a power or disposition for its truth; and <p> is necessary just in case nothing has a power for its falsity. But are there enough powers to go around? In Yates (2015) I argued that in the case of mathematical truths such as <2+2=4>, nothing has the power to bring about their falsity or their truth, which means they come out both (...) necessary and not possible. Combining this with axiom (T), it is easy to derive a contradiction. I suggested that dispositionalists ought to retreat a little and say that <p> is possible just in case either p, or there is a power to bring it about that p, grounding the possibility of mathematical propositions in their truth rather than in powers. Vetter’s (2015) has the resources to provide a response to my argument, and in her (2018) she explicitly addresses it by arguing for a plenitude of powers, based on the idea that dispositions come in degrees, with necessary properties a limiting case of dispositionality. On this view there is a power for <2+2=4>, without there being a power to bring about its truth. In this paper I argue that Vetter’s case for plenitude does not work. However, I suggest, if we are prepared to accept metaphysical causation, a case can be made that there is indeed a power for <2+2=4>. (shrink)

Extant theoretical work on the political resource curse implies that dependence on resource revenues should decrease autocracies’ likelihood of democratizing but not necessarily affect democracies’ chances of survival. Yet most previous empirical studies estimate models that are ill-suited to address this claim. We improve upon earlier studies, estimating a dynamic logit model that interacts a continuous measure of resource dependence with an indicator of regime type using data from 166 countries, covering the period from 1816-2006. We find that an increase (...) in resource dependence at time t - 1 increases the likelihood of autocratic persistence at t, but has no appreciable effect on democratic survival. We go beyond existing empirical studies to show that increases in resource dependence have persistent and substantial cumulative effects on autocracies' likelihood of becoming democratic over the long-term, showing that the total effect of resource dependence on regime type is much larger than the short-term (one period) effect indicates. (shrink)

In this paper, we present three necessary conditions for morally responsible animal research that we believe people on both sides of this debate can accept. Specifically, we argue that, even if human beings have higher moral status than nonhuman animals, animal research is morally permissible only if it satisfies (a) an expectation of sufficient net benefit, (b) a worthwhile-life condition, and (c) a no unnecessary-harm/qualified-basic-needs condition. We then claim that, whether or not these necessary conditions are jointly sufficient conditions of (...) justified animal research, they are relatively demanding with the consequence that many animal experiments may fail to satisfy them. (shrink)

Truthmaker theory promises to do some useful philosophical work: equipping us to argue against phenomenalism and Rylean behaviourism, for instance, and helping us decide what exists (Lewis 1999, 207; Armstrong 1997, 113-119). But it has proved hard to formulate a truthmaker theory that is both useful and believable. I want to suggest that a neglected approach to truthmakers – that of Ian McFetridge – can surmount some of the problems that make other theories of truthmaking unattractive. To begin with, I’ll (...) outline some of the most prominent accounts of truthmaking in the current literature. Then the second part of the paper will explain McFetridge’s theory and argue for its superiority over these accounts. (shrink)

L'ingegneria concettuale è una branca della filosofia caratterizzata da un approccio normativo nei confronti della rappresentazione. Assunzione fondamentale è che i nostri dispositivi rappresentazionali possano essere difettosi. Si configura dunque come l'attività che consiste nell'identificare i difetti in tali dispositivi e mettere in atto strategie di miglioramento. Verranno illustrate le questioni fondamentali a cui una teoria di ingegneria concettuale deve rispondere: in cosa consiste esattamente questa attività? Come possiamo attuarla? Quali meccanismi regolano la formazione dei dispositivi rappresentazionali? Possiamo influire su (...) tali meccanismi? Verrà inoltre presentata un'obiezione all'ingegneria concettuale e varie risposte. -/- Conceptual engineering is a branch of philosophy characterised by a normative approach towards representation. The fundamental assumption of it is that our representational devices can be defective. Conceptual engineering is then the activity consisting of identifying the defects of such devices and putting in place ameliorative strategies. This paper illustrates the fundamental issues for a theory of conceptual engineering: what does this activity consist of? How can we implement it? What mechanisms regulate the formation of representational devices? Can we have an influence over those mechanisms? Moreover, it will be presented an objection to conceptual engineering and various responses to it. (shrink)

Epistemologists have recently proposed a number of norms governing rational inquiry. My aim in this paper is to unify and explain recently proposed norms of inquiry by developing a general account of the conditions under which inquiries are rational, analogous to theories such as evidentialism and reliabilism for rational belief. I begin with a reason-responsiveness conception of rationality as responding correctly to possessed normative reasons. I extend this account with a series of claims about the normative reasons for inquiry that (...) we possess. I apply the account to shed light on two classes of norms that have featured prominently in recent discussions: norms of clutter avoidance forbidding agents from engaging in trivial inquiries, and norms of logical non-omniscience governing properties such as the deductive closure and consistency of an agent's belief state. I conclude with a discussion of the sense in which norms of inquiry should be regarded as epistemic norms. (shrink)

Fichte-Studien, volume 49 (Leiden: Brill/Rodopi Publishers, 8 April 2021), edited by David W. Wood, 471pp. -/- Presenting new critical perspectives on J.G. Fichte’s Wissenschaftslehre, this volume of articles in English by an international group of scholars addresses the topic of first principles in Fichte’s writings. Especially discussed are the central text of his Jena period, the 1794/95 Grundlage der gesammten Wissenschaftslehre, as well as later versions like the Wissenschaftslehre nova methodo (1796-99) and the presentations of 1804 and 1805. Also (...) included are new studies on the first principles of the particular sub-disciplines of Fichte’s system, such as the doctrines of aesthetics, nature, right, ethics, and history. The volume also contains a number of miscellaneous essays on Fichte research, as well as several book reviews. (shrink)

David Heyd's study will stimulate philosophers to recognise the importance of the rather neglected topic of the distinctiveness of supererogation and the ...

This is a corrected version of the final proofs. I've fixed a number of typos, and corrected a blunder in chapter 4. In chapter 4 I say that 'this is this' is analytic, and 'this is not this' is antonymous. This is inconsistent with what I say in chapter 5, and not what I actually think. Rather, 'this is this' is taugologous, and 'this is not this' is contradictory. Analyticity and autnonmy are sense properties while tautologousness and contradictoriness are formal (...) logical properties. Heading, ToC and Index updated accordingly. (Oxford will make these corrections in their online version and in future print runs.). (shrink)

Longtermism is the thesis that in a large class of decision situations, the best thing we can do is what is best for the long-term future. The scope question for longtermism asks: how large is the class of decision situations for which this is true? In this paper, I suggest that the scope of longtermism may be narrower than many longtermists suppose. I identify a restricted version of longtermism: swamping axiological strong longtermism (swamping ASL). I identify three scope-limiting factors - (...) probabilistic and decision-theoretic phenomena which, when present, tend to reduce the prospects for swamping ASL. I argue that these scope-limiting factors are often present in human decision problems, then use two case studies from recent discussions of longtermism to show how the scope-limiting factors lead to a restricted, if perhaps nonempty, scope for swamping ASL. (shrink)

People are often offended by beliefs, expect apologies for beliefs, apologize for their own beliefs. In many mundane cases, people are morally criticized for their beliefs. Intuitively, then, beliefs seem to sometimes wrong people. Recently, the philosophical literature has picked up on this theme, and has started to discuss it under the heading of doxastic wrongdoing. In this paper we argue that despite the strength of such initial intuitions, at the end of the day they have to be rejected. If (...) it can be ever truthfully asserted that beliefs wrong, this is always derivative – beliefs wrong only in virtue of other things (like evidence-gathering actions) wronging. We distinguish between modest and ambitious doxastic wrongdoing theories (the former deny, while the latter accept, the possibility of a morally wrong yet epistemically permissible belief); we argue that each of these options faces insurmountable problems; and we offer partly debunking explanations of the intuitions purportedly supporting doxastic wrongdoing. (shrink)

Recent methodological debates regarding the place of feasibility considerations in normative political theory are hindered for want of a rigorous model of the feasibility frontier. To address this shortfall, I present an analysis of feasibility that generalizes the economic concept of a production possibility frontier and then develop a rigorous model of the feasibility frontier using the familiar possible worlds technology. I then show that this model has significant methodological implications for political philosophy. On the Target View, a political ideal (...) presents a long-term goal for morally progressive reform efforts and, thus, serves as an important reference point for our specification of normative political principles. I use the model to show that we can- not reasonably expect that adopting political ideals as long-term reform objectives will guide us toward the realization of morally optimal feasible states of affairs. I conclude by proposing that political philosophers turn their attention to the analysis of actual social failures rather than political ideals. (shrink)

Numerous philosophers allege that the "general theory of second best" (Lipsey and Lancaster, 1956) poses a challenge to the Target View, which asserts that real world reform efforts should aim to establish arrangements that satisfy the constitutive features of ideal just states of affairs. I demonstrate two claims that are relevant in this context. First, I show that the theory of second best fails to present a compelling challenge to the Target View in general. But, second, the theory of second (...) best requires ideal theorists to undertake certain kinds of causal and comparative analyses that are typically thought to lie beyond the borders of conventional ideal theory. (shrink)

Many philosophers have claimed that the folk endorse moral universalism. Some have taken the folk view to support moral universalism; others have taken the folk view to reflect a deep confusion. And while some empirical evidence supports the claim that the folk endorse moral universalism, this work has uncovered intra-domain differences in folk judgments of moral universalism. In light of all this, our question is: why do the folk endorse moral universalism? Our hypothesis is that folk judgments of moral universalism (...) are generated in part by a desire to punish. We present evidence supporting this across three studies. On the basis of this, we argue for a debunking explanation of folk judgments of moral universalism. Our results not only further our understanding of the psychological processes underpinning folk judgments of moral universalism. They also bear on philosophical discussions of folk meta-ethics. (shrink)

Chapter 20 David Kovacs’ “Essence, Grounding, and Explanation” sets out four different ways in which essence might be taken to relate to the notion of grounding or metaphysical explanation, i.e., the type of connection that is often expressed by means of non-causal “in virtue of” or “because”-claims: (i) Unity: essence and grounding belong to a unified set of explanatory concepts; (ii) Supplementation: essence and grounding both contribute in their own way to a distinctive type of explanation; (iii) Independence: essence (...) is a sui generis notion with no straightforward conceptual links to grounding; and (iv) Irrelevance: essence is not an explanatory notion at all and therefore should not be viewed as connected to explanatory notions like grounding. As Kovacs brings out in the chapter, a wide variety of attitudes are represented in the literature even among philosophers who are sympathetic to the recent “hyperintensional” turn in metaphysics when it comes to the question of how the notions of essence and grounding interact with one another. (shrink)

This paper examines the philosophical significance of the consequence relation defined in the $\Omega$-logic for set-theoretic languages. I argue that, as with second-order logic, the hyperintensional profile of validity in $\Omega$-Logic enables the property to be epistemically tractable. Because of the duality between coalgebras and algebras, Boolean-valued models of set theory can be interpreted as coalgebras. In Section \textbf{2}, I demonstrate how the hyperintensional profile of $\Omega$-logical validity can be countenanced within a coalgebraic logic. Finally, in Section \textbf{3}, the philosophical (...) significance of the characterization of the hyperintensional profile of $\Omega$-logical validity for the philosophy of mathematics is examined. I argue (i) that $\Omega$-logical validity is genuinely logical, and (ii) that it provides a hyperintensional account of formal grasp of the concept of `set'. Section \textbf{4} provides concluding remarks. (shrink)

This essay examines the philosophical significance of $\Omega$-logic in Zermelo-Fraenkel set theory with choice (ZFC). The categorical duality between coalgebra and algebra permits Boolean-valued algebraic models of ZFC to be interpreted as coalgebras. The hyperintensional profile of $\Omega$-logical validity can then be countenanced within a coalgebraic logic. I argue that the philosophical significance of the foregoing is two-fold. First, because the epistemic and modal and hyperintensional profiles of $\Omega$-logical validity correspond to those of second-order logical consequence, $\Omega$-logical validity is genuinely (...) logical. Second, the foregoing provides a hyperintensional account of the interpretation of mathematical and metamathematical vocabulary. (shrink)

Two hundred and sixty-three subjects each gave examples for one of five geographic categories: geographic features, geographic objects, geographic concepts, something geographic, and something that could be portrayed on a map. The frequencies of various responses were significantly different, indicating that the basic ontological terms feature, object, etc., are not interchangeable but carry different meanings when combined with adjectives indicating geographic or mappable. For all of the test phrases involving geographic, responses were predominantly natural features such as mountain, river, lake, (...) ocean, hill. Artificial geographic features such as town and city were listed hardly at all for geographic categories, an outcome that contrasts sharply with the disciplinary self-understanding of academic geography. However, geographic artifacts and fiat objects, such as roads, cities, boundaries, countries, and states, were frequently listed by the subjects responding to the phrase something that could be portrayed on a map. In this paper, we present the results of these experiments in visual form, and provide interpretations and implications for further research. (shrink)

Are demands for equality motivated by envy? Nietzsche, Freud, Hayek, and Nozick all thought so. Call this the Envy Objection. For egalitarians, the Envy Objection is meant to sting. Many egalitarians have tried to evade the Envy Objection.. But should egalitarians be worried about envy? In this paper, I argue that egalitarians should stop worrying and learn to love envy. I argue that the persistent unwillingness to embrace the Envy Objection is rooted in a common misunderstanding of the nature of (...) the charge, what it reveals, and what can be said in response to it. I develop what Bernard Williams might call a vindicatory genealogy of envy, thereby allowing us to see that envy, rather than undermining egalitarian intuitions, can in fact play a distinct justificatory role (when it is fitting), which undermines the Envy Objection. (shrink)

This paper aims to provide hyperintensional foundations for mathematical platonism. I examine Hale and Wright's (2009) objections to the merits and need, in the defense of mathematical platonism and its epistemology, of the thesis of Necessitism. In response to Hale and Wright's objections to the role of epistemic and metaphysical modalities in providing justification for both the truth of abstraction principles and the success of mathematical predicate reference, I examine the Necessitist commitments of the abundant conception of properties endorsed by (...) Hale and Wright and examined in Hale (2013), and demonstrate how a two-dimensional approach to the epistemology of mathematics is consistent with Hale and Wright's notion of there being non-evidential epistemic entitlement rationally to trust that abstraction principles are true. A choice point that I flag is that between availing of intensional or hyperintensional semantics. The hyperintensional semantic approach that I advance is a topic-sensitive epistemic two-dimensional truthmaker semantics. I countenance a hyperintensional semantics for novel epistemic abstractionist modalities. I suggest that observational type theory can be applied to first-order abstraction principles in order to make abstraction principles recursively enumerable. Epistemic and metaphysical states and possibilities may thus be shown to play a constitutive role in vindicating the reality of mathematical objects and truth, and in providing a conceivability-based route to the truth of abstraction principles as well as other axioms and propositions in mathematics. (shrink)