Identity and Difference consists of English translations and the original German versions of two little-known lectures given in 1957 by Martin Heidegger, "The Principle of Identity" and "The Onto-theo-logical Constitution of Metaphysics.

When philosophers address personal identity, they usually explore numerical identity: what are the criteria for a person's continuing existence? When non-philosophers address personal identity, they often have in mind narrative identity: Which characteristics of a particular person are salient to her self-conception? This book develops accounts of both senses of identity, arguing that both are normatively important, and is unique in its exploration of a range of issues in bioethics through the lens of identity. (...) Defending a biological view of our numerical identity and a framework for understanding narrative identity, DeGrazia investigates various issues for which considerations of identity prove critical: the definition of death; the authority of advance directives in cases of severe dementia; the use of enhancement technologies; prenatal genetic interventions; and certain types of reproductive choices. He demonstrates the power of personal identity theory to illuminate issues in bioethics as they bring philosophical theory to life. (shrink)

Gender Identity: What It Is and Why It Matters is the first book in philosophy focusing on gender identity and transgender rights. To be trans is to have a gender identity different from the gender you were assigned at birth. But what is it to have a gender identity? The first part of the book develops a new account of our gender identity as the gender that seems to us to fit us. This subjective fit (...) account of gender identity fits with trans people’s testimony, explains why gender identities deserve respect, explains how we can discover our gender identity, explains why gender identities are practically important, and provides a good account of cis and trans and non-binary and binary gender identities. The second part of the book develops a new understanding of trans rights to gender marker change, legal gender recognition, gender-affirming healthcare, and sporting participation and accommodation. It develops an integrity-based account of trans rights on which these trans rights arise from basic liberal rights to live with integrity, to live in line with your judgements of how you ought to live, and what a good or meaningful life for you involves. Rights to live with integrity ground basic liberal rights to freedom of religious belief and expression. This book argues that they also ground trans rights. The second part of the book also addresses a wide range of gender critical feminist philosophers’ arguments against trans rights and shows that these arguments fail. (shrink)

_Identity and Discrimination_, originally published in 1990 and the first book by respected philosopher Timothy Williamson, is now reissued and updated with the inclusion of significant new material. Williamson here proposes an original and rigorous theory linking identity, a relation central to metaphysics, and indiscriminability, a relation central to epistemology.__ Updated and reissued edition of Williamson’s first publication, with the inclusion of significant new material Argues for an original cognitive account of the relation between identity and discrimination that (...) has been influential in the philosophy of perception Pioneers the use of epistemic logic to solve puzzles about indiscriminability Develops the application of techniques from mathematical logic to understand issues about identity over time and across possible worlds. (shrink)

Personal identity deals with questions about ourselves qua people (or persons). Many of these questions are familiar ones that occur to everyone at some time: What am I? When did I begin? What will happen to me when I die? Discussions of personal identity go right back to the origins of Western philosophy, and most major figures have had something to say about it. (There is also a rich literature on personal identity in Eastern philosophy, which I (...) am not competent to discuss. Collins 1982 is a good source.). (shrink)

Identity has long been treated as a metaphysical primitive, defined by material continuity, causal chains, psychological persistence, narrative coherence, or sortal concepts. These domain-specific accounts succeed locally but fail to generalize across organisms, artificial systems, mathematical structures, and institutions. This work develops a unified, substrate-independent theory of identity based not on continuity or essence but on constraint geometry: identity is a region of invariance within a possibility space determined by structural constraints, dynamical constraints, and an interpretive frame. (...) This framework distinguishes three canonical forms—point identity (instantaneous coherence), field identity (episodic or bounded coherence), and flow identity (generative persistence)—showing that debates about personal identity, biological individuality, and computational unity are arguments about scale and invariance, not metaphysics. The theory subsumes and clarifies two recent approaches: PatternSense, which characterizes persistent generative identity, and ODEI, which characterizes episodic identity in artificial systems. It also explains identity drift, bifurcation, fusion, and extinction in geometric terms. The result is a general identity theory applicable to persons, organisms, AI systems, institutions, and formal structures. It replaces metaphysical disputes with a precise structural foundation: identity is not a substance or a story but a constraint-induced invariance pattern across scales. (shrink)

We first motivate and explain an attitude-dependent view of personal identity on which an AI system’s identity conditions are determined by its pattern of self-concern. We show that this view has important implications for the moral obligations we would have to AI moral patients. Self-concern, we contend, could also be used to predict, explain, and manipulate AI’s self-interested behavior in safety-relevant ways. The role that self-concern could play for AI identity, rights and safety generates desiderata on what (...) self-concern should be like. To meet these desiderata, we argue that self-concern comprises belief-like self-representations as well as desire-like aspects and functionally related motivational, evaluative, and affective states. Finally, we explore how mechanistic interpretability and behavioral methods can be combined to measure self-concern in language models. Our argument suggests that a scientific understanding of language model self-concern is not only a crucial missing piece for debates on AI identity, rights, and safety, but also empirically tractable. (shrink)

I propose formulating identity criteria as generic statements of ground, thereby avoiding objections that have been made to the more usual formulations.

The topic of personal identity has prompted some of the liveliest and most interesting debates in recent philosophy. In a fascinating new contribution to the discussion, Peter Unger presents a psychologically aimed, but physically based, account of our identity over time. While supporting the account, he explains why many influential contemporary philosophers have underrated the importance of physical continuity to our survival, casting a new light on the work of Lewis, Nagel, Nozick, Parfit, Perry, Shoemaker, and others. Deriving (...) from his discussion of our identity itself, Unger produces a novel but commonsensical theory of the relations between identity and some of our deepest concerns. In a conservative but flexible spirit, he explores the implications of his theory for questions of value and of the good life. (shrink)

Are identity criteria grounding principles? A prima facie answer to this question is positive. Specifically, two-level identity criteria can be taken as principles related to issues of identity among objects of a given kind compared with objects of a more basic kind. Moreover, they are grounding metaphysical principles of some objects with regard to others. In the first part of the paper we criticise this prima facie natural reading of identity criteria. This result does not mean (...) that identity criteria could not be taken as grounding principles. In the second part, we propose some basic steps towards a conceptual reading of grounding. Such a way of understanding it goes along with an epistemic reading of identity criteria. (shrink)

This monograph develops a unified theoretical framework for understanding identity as a recursive informational process. It analyzes identity not as a property of a substrate but as a dynamic, self‑referential architecture that generates continuity across temporal, contextual, and systemic transformations. The framework identifies three foundational structural principles—Integration, Coherence, and Recursive Coupling—as the minimal grammar through which identity‑bearing patterns emerge, stabilize, and evolve. The model explains how systems maintain continuity through fixed‑point dynamics, nonlinear feedback, and path‑dependent self‑organization, independent (...) of any specific material realization. A structure‑before‑discipline orientation grounds the approach, deriving explanatory force from minimal structural conditions rather than domain‑specific conceptual traditions. A Systemic Pattern‑Structure Analysis (SMSA) is used to identify the smallest necessary set of structural relations from which recursive identity arises. An accompanying Entry Note provides an accessible orientation to the core intuition and conceptual posture of the framework, outlining the minimal conditions required for identity to emerge as a process. Together, the monograph and the Entry Note offer a coherent theoretical basis for system‑theoretical, computational, and structural approaches to identity. (shrink)

Identity-protective reasoning---motivated reasoning driven by defending a social identity---is often dismissed as a paradigm of epistemic vice and a key driver of democratic dysfunction. Against this view, I argue that identity-protective reasoning can play a positive epistemic role, both individually and collectively. Collectively, it facilitates an effective division of cognitive labor by enabling groups to test divergent beliefs, serving as an epistemic insurance policy against the possibility that the total evidence is misleading. Individually, it can correct for (...) the distortions that arise from taking ideologically skewed evidence at face value. This is particularly significant for members of marginalized groups, who frequently encounter evidence that diminishes the value of their identities, beliefs, and practices. For them, identity-protective reasoning can counter dominant ideological ignorance and foster resistant standpoint development. While identity-protective reasoning is not without risks, its application from marginalized and counter-hegemonic positions carries epistemic benefits crucial in democracies threatened by elite capture. Against dominant views in contemporary political epistemology and psychology, identity-protective reasoning should be reconceived as a resource to be harnessed and not a problem to be eradicated. (shrink)

Phineas Gage’s story is typically offered as a paradigm example supporting the view that part of what matters for personal identity is a certain magnitude of similarity between earlier and later individuals. Yet, reconsidering a slight variant of Phineas Gage’s story indicates that it is not just magnitude of similarity, but also the direction of change that affects personal identity judgments; in some cases, changes for the worse are more seen as identity-severing than changes for the better (...) of comparable magnitude. Ironically, thinking carefully about Phineas Gage’s story tells against the thesis it is typically taken to support. (shrink)

The study of identity crosses all disciplinary borders to address such issues as the multiple interactions of race, class, and gender in feminist, lesbian, and gay studies, postcolonialism and globalization, and the interrelation of nationalism and ethnicity in ethnic and area studies. Identities will help disrupt the cliche-ridden discourse of identity by exploring the formation of identities and problem of subjectivity. Leading scholars in literary criticism, anthropology, sociology, and philosophy explore such topics as "Gypsies" in the Western imagination, (...) the mobilization of the West in Chinese television, the lesbian identity and the woman's gaze in fashion photography, and the regulation of black women's bodies in early 20th-century urban areas. This collection of twenty articles brings together the special issue of Critical Inquiry entitled "Identities" (Summer 1992), two other previously published essays, and five previously published critical responses and rejoinders, all of which is interrogated in two new essays by Michael Gorra and Judith Butler. Contributors include Elizabeth Abel, Kwame Anthony Appiah, Akeel Bilgrami, Daniel Boyarin, Jonathan Boyarin, Judith Butler, Hazel V. Carby, Xiaomei Chen, Diana Fuss, Henry Louis Gates, Jr., Avery Gordon, Michael Gorra, Cheryl Herr, Saree S. Makdisi, Walter Benn Michaels, Christopher Newfield, Gananath Obeyesekere, Molly Anne Rothenberg, Gayatri Chakravorty Spivak, Sara Suleri, Katie Trumpener, and Joseph Valente. (shrink)

Our aim in this entry is to articulate the state of the art in the moral psychology of personal identity. We begin by discussing the major philosophical theories of personal identity, including their shortcomings. We then turn to recent psychological work on personal identity and the self, investigations that often illuminate our person-related normative concerns. We conclude by discussing the implications of this psychological work for some contemporary philosophical theories and suggesting fruitful areas for future work on (...) personal identity. (shrink)

Terence Parsons presents a lively and controversial study of philosophical questions about identity. Because many puzzles about identity remain unsolved, some people believe that they are questions that have no answers and that there is a problem with the language used to formulate them. Parsons explores a different possibility: that such puzzles lack answers because of the way the world is (or because of the way the world is not). He claims that there is genuine indeterminacy of (...) class='Hi'>identity in the world. He articulates such a view in detail and defends it from a host of criticisms. (shrink)

This book analyzes metaphysical consequences of the quantum theory of many particles with respect to the fundamental notions of identity, individuality and discernibility. The main focus is on the proper interpretation of the quantum formalism in relation to the role of permutation invariance and the adequate representation of the properties of individual subsystems. Two main approaches to the issue of the individuation of quantum particles are distinguished and thoroughly discussed. These approaches differ radically with respect to their metaphysical consequences (...) – while one of them implies the complete indiscernibility of quantum particles of the same kind, the other one restores the possibility of discerning individual particles by their properties. We connect the problem of quantum individuation and discernibility with an analysis of the concept of quantum entanglement, and we also discuss identity over time and in counterfactual scenarios. (shrink)

Identity politics has been critiqued in various ways. One central problem—the Reinforcement Problem—claims that identity politics reinforces groups rooted in oppression thereby undermining its own liberatory aims. Here I consider two versions of the problem—one psychological and one metaphysical. I defang the first by drawing on work in social psychology. I then argue that careful consideration of the metaphysics of social groups and of the practice of identity politics provides resources to dissolve the second version. Identity (...) politics involves the creation or transformation of groups in ways that do not succumb to the metaphysical Reinforcement Problem. (shrink)

This book gathers together thirteen of Peter van Inwagen's essays on metaphysics, several of which have acquired the status of modern classics in their field. They range widely across such topics as Quine's philosophy of quantification, the ontology of fiction, the part-whole relation, the theory of 'temporal parts', and human knowledge of modal truths. In addition, van Inwagen considers the question as to whether the psychological continuity theory of personal identity is compatible with materialism, and defends the thesis that (...) possible states of affairs are abstract objects, in opposition to David Lewis's 'extreme modal realism'. A specially-written introduction completes the collection, which will be an invaluable resource for anyone interested in metaphysics. (shrink)

The mathematical rules used to handle systems of identical quantum particles bring into question whether the elementary constituents of matter, such as electrons, have the fundamental characteristics of persistence and reidentifiability that are usually attributed to classical particles. However, despite considerable philosophical debate, the metaphysical profile of these entities remains elusive. -/- Previous debates have taken the mathematical rules, and the language in which these are usually couched, as a starting point. Here, we argue that this methodology is inherently limited, (...) and develop a new conception of identical particles based on a recent mathematical reconstruction of these rules. Using this reconstruction, we demonstrate that the special behaviour of identical particles originates in the confluence of identicality and the active nature of the quantum measurements. We propose that identical particles are appropriately viewed as potential parts of a whole, and show how this leads to striking consequences such as restricted transtemporal identity. (shrink)

The author attacks the view that identity, Like largeness, Is a relative relation. The primary advocate of the view that identity is relative is p.T. Geach. It is argued that geach has not shown that the failure of the identity of indiscernibles principle, As a truth of logic, Forces us to stop taking indiscernibility within particular formal theories or languages as a sufficient condition for identity. The author also argues that the whole notion of relative (...) class='Hi'>identity, As explicated by geach, Is very probably incoherent. (shrink)

Putative counterexamples to the Principle of Identity of Indiscernibles (PII) are notoriously inconclusive. I establish ground rules for debate in this area, offer a new response to such counterexamples for friends of the PII, but then argue that no response is entirely satisfactory. Finally, I undermine some positive arguments for PII.

This is an expanded edition of Sydney Shoemaker's seminal collection of his work on interrelated issues in the philosophy of mind and metaphysics. It reproduces all of the original papers, many of which are now regarded as classics, and includes four papers published since the first edition appeared in 1984. Themes include the nature of self-knowledge and self-reference, personal identity, persistence over time, properties, mental states, and perceptual experience.A number of the papers, including 'Self-Reference and Self-Awareness', 'Persons and Their (...) Pasts', 'Causality and Properties', and 'The Inverted Spectrum', have remained at the centre of discussion of their topics. Several of the essays in the original collection discuss the ways in which causal considerations enter into the individuation of properties, and three of the added essays - 'Causal and Metaphysical Necessity', 'Realization and Mental Causation', and 'On What There Are' - deal with related themes. The neo-Lockean view of personal identity presented in 'Persons and Their Pasts' is developed with a different emphasis in the added paper 'Self and Substance'.Identity, Cause, and Mind's reappearance will be warmly welcomed by scholars and students alike. (shrink)

Identity-Relative Paternalism, as defended by Wilkinson, holds that paternalistic intervention is justified to prevent an individual from doing to their future selves (where there are weakened prudential unity relations between the current and future self) what it would be justified to prevent them from doing to others.1 Wilkinson, drawing on the work of Parfit and others, defends the notion of Identity-Relative Paternalism from a series of objections. I argue here, however, that Wilkinson overlooks a significant problem for (...) class='Hi'>Identity-Relative Paternalism—namely, that it yields unactionable and self-contradictory results when applied to choices where both options present potential harms to future selves. (shrink)

Identity criteria are powerful tools for the metaphysician. They tell us when items are identical or distinct. Some varieties of identity criteria also try to explain in virtue of what items are identical or distinct. This Element has two objectives: to discuss formulations of identity criteria and to take a closer look at one notorious criterion of object identity, Leibniz's Law. The first section concerns the form of identity criteria. The second section concerns the better-regarded (...) half of Leibniz's Law, the indiscernibility of identicals. The third section turns to the more controversial half of Leibniz's Law, the identity of indiscernibles. The author considers alternatives to Leibniz's Law as well as the possibility that there are no adequate identity criteria to be found. (shrink)

Personal Identity and Ethics provides a lively overview of the relationship between the metaphysics of personal identity and ethics. How does personal identity affect our ethical judgments? It is a commonplace to hold that moral responsibility for past actions requires that the responsible agent is in some relevant respect identical to the agent who performed the action. Is this true? On the other hand, can ethics constrain our account of personal identity? Do the practical requirements of (...) moral theory commit us to holding that persons do remain identical over time? Or is it the case that personal identity is not, in fact, relevant to ethics? -/- Shoemaker provides the first comprehensive examination of these issues for the undergraduate audience. Topics include personal identity and prudential rationality; personal identity's significance for moral responsibility and ethical theory; and the practical consequences of accounts of personal identity for issues such as abortion, stem cell research, cloning, advance directives, populations ethics, multiple personality disorder, and the definition of death. (shrink)

A theory of gender ought to be compatible with trans-inclusive definitions of gender identity terms, such as ‘woman’ and ‘man’. Appealing to this principle of trans-inclusion, Katharine Jenkins argues that we ought to endorse a dual social position and identity theory of gender. Here, I argue that Jenkins’s dual theory of gender fails to be trans-inclusive for the following reasons: it cannot generate a definition of ‘woman’ that extends to include all trans women, and it understands transgender gender (...) identity through a cisgender frame. (shrink)

An encyclopedia entry providing an overview of the philosophical issues entailed in the theory and practice of "identity politics." Open access and online. Regularly updated.

In this paper I outline and defend a new approach to personal-identity—personal-identity non-cognitivism—and argue that it has several advantages over its cognitivist rivals. On this view utterances of personal-identity sentences express a non-cognitive attitude towards relevant person-stages. The resulting view offers a pleasingly nuanced picture of what we are doing when we utter such sentences.

I explore proposals for stating identity criteria in terms of ground. I also address considerations for and against taking identity and distinctness facts to be ungrounded.

The personal identity relation is of great interest to philosophers, who often consider fictional scenarios to test what features seem to make persons persist through time. But often real examples of neuroscientific interest also provide important tests of personal identity. One such example is the case of Phineas Gage – or at least the story often told about Phineas Gage. Many cite Gage’s story as example of severed personal identity; Phineas underwent such a tremendous change that Gage (...) “survived as a different man.” I discuss a recent empirical finding about judgments about this hypothetical. It is not just the magnitude of the change that affects identity judgment; it is also the negative direction of the change. I present an experiment suggesting that direction of change also affects neuroethical judgments. I conclude we should consider carefully the way in which improvements and deteriorations affect attributions of personal identity. This is particularly important since a number of the most crucial neuroethical decisions involve varieties of cognitive enhancements or deteriorations. (shrink)

How can we think about identities in the wake of feminist critiques of identity and identity politics? Allison Weir rethinks conceptions of individual and collective identities in relation to freedom.

Goffman’s (1959) dramaturgical identity theory requires modification when theorising about presentations of self on social media. This chapter contributes to these efforts, refining a conception of digital identities by differentiating them from ‘corporatised identities’. Armed with this new distinction, I ultimately argue that social media platforms’ production of corporatised identities undermines their users’ autonomy and digital well-being. This follows from the disentanglement of several commonly conflated concepts. Firstly, I distinguish two kinds of presentation of self that I collectively refer (...) to as ‘expressions of digital identity’. These digital performances (boyd 2007) and digital artefacts (Hogan 2010) are distinct, but often confused. Secondly, I contend this confusion results in the subsequent conflation of corporatised identities – poor approximations of actual digital identities, inferred and extrapolated by algorithms from individuals’ expressions of digital identity – with digital identities proper. Finally, and to demonstrate the normative implications of these clarifications, I utilise MacKenzie’s (2014, 2019) interpretation of relational autonomy to propose that designing social media sites around the production of corporatised identities, at the expense of encouraging genuine performances of digital identities, has undermined multiple dimensions of this vital liberal value. In particular, the pluralistic range of authentic preferences that should structure flourishing human lives are being flattened and replaced by commercial, consumerist preferences. For these reasons, amongst others, I contend that digital identities should once again come to drive individuals’ actions on social media sites. Only upon doing so can individuals’ autonomy, and control over their digital identities, be rendered compatible with social media. (shrink)

In the present study, we tested whether civic identity consisting of moral and political identity via the bifactor model of civic identity with the Stanford Civic Purpose dataset. Previous research in youth development proposed that civic identity consists of two closely related identity constructs, i.e., moral and political identity. Given the bifactor model in factor analysis assumes the presence of both the general and specific factors, we hypothesized that the bifactor model would better fit (...) the data than conventional alternative models. Thus, we compared the candidate models, including the bifactor model, with confirmatory factor analysis. To address the concern about the potential overfitting of the bifactor model, we additionally conducted cross-validation and measurement invariance tests across different gender groups and time points. The analysis results supported our hypothesis that the bifactor model better fitted the data. Both the cross-validation and measurement invariance test results suggested that the overfitting issue was not a significant concern. In the present study, we empirically demonstrated that the bifactor model of civic identity consisting of moral and political identity, which was supposed to be more consistent with the theoretical and conceptual framework of civic identity, better fitted the data than conventional alternative models. (shrink)

This topical new book by Zygmunt Bauman explores the notion of identity in the modern world. As we grapple with the insecurity and uncertainty of liquid modernity, Bauman argues that our socio-political, cultural, professional, religious and sexual identities are undergoing a process of continual transformation. Identities the world over have become more precarious than ever: we live in an era of constant change and disposability - whether it's last season's outfit, or car, or even partner - and our identities (...) as a result have become transient and deeply elusive. In a world of rapid global change where national borders are increasingly eroded, our identities are in a state of continuous flux. Identity - a notion that by its very nature is elusive and ambivalent - has become a key concept for understanding the changing nature of social life and personal experience in our contemporary, liquid modern age. In this brief book, Zygmunt Bauman explains compellingly why this is so. (shrink)

The eleven new papers in this volume address fundamental and interrelated philosophical issues concerning modality and identity, issues that were pivotal to the development of analytic philosophy in the twentieth century, and remain a key focus of debate in the twenty-first. Identity and Modality brings together leading researchers in metaphysics, the philosophy of mind, the philosophy of science, and the philosophy of mathematics.

Background: Recent literature on addiction and judgments about the characteristics of agents has focused on the implications of adopting a ‘brain disease’ versus ‘moral weakness’ model of addiction. Typically, such judgments have to do with what capacities an agent has (e.g., the ability to abstain from substance use). Much less work, however, has been conducted on the relationship between addiction and judgments about an agent’s identity, including whether or to what extent an individual is seen as the same person (...) after becoming addicted. Methods: We conducted a series of vignette-based experiments (total N = 3,620) to assess lay attitudes concerning addiction and identity persistence, systematically manipulating key characteristics of agents and their drug of addiction. Conclusions: In Study 1, we found that US participants judged an agent who became addicted to drugs as being closer to ‘a completely different person’ than ‘completely the same person’ as the agent who existed prior to the addiction. In Studies 2-6, we investigated the intuitive basis for this result, finding that lay judgments of altered identity as a consequence of drug use and addiction are driven primarily by perceived negative changes in the moral character of drug users, who are seen as having deviated from their good true selves. (shrink)

According to classical physics particles are basic building blocks of the world. These classical particles are distinguishable objects, individuated by unique combinations of physical properties. By contrast, in quantum mechanics the received view is that particles of the same kind are physically indistinguishable from each other and lack identity. This doctrine rests on the quantum mechanical symmetrization postulates together with the “factorist” assumption that each single particle is represented in exactly one factor space of the tensor product Hilbert space (...) of a many-particle system. Even though standard in theoretical physics and the philosophy of physics, the assumption of factorism and the ensuing indistinguishability of particles are problematic. Particle indistinguishability is irreconcilable with the everyday meaning of “particle”, and also with how this term is used in the practice of physics. Moreover, it is a consequence of the standard view that identical quantum particles remain indistinguishable even in the classical limit, which makes a smooth transition to the classical particle concept impossible. Lubberdink and Dieks and Lubberdink have proposed an alternative conception of quantum particles that does not rely on factorism and avoids these difficulties. We further explain and discuss this alternative framework here. One of its key consequences is that particles in quantum theory are not fundamental but emergent; another that once they have emerged, quantum particles are always physically distinguishable and thus possess a physically grounded identity. (shrink)

We critically examine the claim that identity is a fundamental concept. According to those putting forward this thesis, there are four related reasons that can be called upon to ground the fundamental character of identity: identity is presupposed in every conceptual system; identity is required to characterize individuality; identity cannot be defined; the intelligibility of quantification requires identity. We address each of these points and argue that none of them advances compelling reasons to hold (...) that identity is fundamental; in fact, most of the tasks that seem to require identity may be performed without identity. So, in the end, identity may not be a fundamental concept after all. (shrink)

Many philosophers hypothesize that our concept of personal identity is partly constituted by the one-person-one-place rule, which states that a person can only be in one place at a time. This hypothesis has been assumed by the most influential contemporary work on personal identity. In this paper, we report a series of studies testing whether the hypothesis is true. In these studies, people consistently judged that the same person existed in two different places at the same time. This (...) result undermines some widely held philosophical assumptions, supports others, and fits well with recent discoveries on identity judgments about inanimate objects and non-human animals. (shrink)

This paper develops a theory of propositional identity which distinguishes necessarily equivalent propositions that differ in subject-matter. Rather than forming a Boolean lattice as in extensional and intensional semantic theories, the space of propositions forms a non-interlaced bilattice. After motivating a departure from tradition by way of a number of plausible principles for subject-matter, I will provide a Finean state semantics for a novel theory of propositions, presenting arguments against the convexity and nonvacuity constraints which Fine (2016, 2017a,b) introduces. (...) I will then move to compare the resulting logic of propositional identity (PI) with Correia’s (2016) logic of generalised identity (GI), as well as the first degree fragment of Angell’s (1989) logic of analytic containment (AC). The paper concludes by extending PI to include axioms and rules for a subject-matter operator, providing a much broader theory of subject-matter than the principles with which I will begin. (shrink)