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)

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)

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)

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)

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)

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)

_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)

Can there be two things that are completely indistinguishable? This simple question has raised numerous debates throughout the history of philosophy and science. The principle of the identity of indiscernibles claims that no two things can be completely indiscernible. But this thesis has been challenged in quantum physics and continues to be a hot topic in cutting edge areas of mathematics. The question has gained a renewed interest with the possibility of harnessing indistinguishability as a resource in quantum information (...) tasks. This theme issue is devoted to understanding identity and indistinguishability in philosophy and science, gathering an interdisciplinary group of experts in the field. It will allow readers of diverse disciplines to have an updated introduction to the topic. (shrink)

The essays collected in this volume address a range of issues that arise when the focus of philosophical reflection on identity is shifted from metaphysical to practical and evaluative concerns. They also explore the usefulness of the notion of narrative for articulating and responding to these issues. The chapters, written by an outstanding roster of international scholars, address a range of complex philosophical issues concerning the relationship between practical and metaphysical identity, the embodied dimensions of the first-personal perspective, (...) the kind of reflexive agency involved in the self-constitution of one’s practical identity, the relationship between practical identity and normativity, and the temporal dimensions of identity and selfhood. In addressing these issues, contributors engage with debates in the literatures on personal identity, phenomenology, moral psychology, action theory, normative ethical theory, and feminist philosophy. (shrink)

Uses insights from Kierkegaard to explore contemporary problems of self, time, narrative and death Is each of us the main character in a story we tell about ourselves, or is this narrative understanding of selfhood misguided and possibly harmful? Are selves and persons the same thing? And what does the possibility of sudden death mean for our ability to understand the narrative of ourselves? These questions have been much discussed both in recent philosophy and by scholars grappling with the work (...) of the enigmatic 19th-century thinker Søren Kierkegaard. For the first time, this collection brings together figures in both contemporary philosophy and Kierkegaard studies to explore pressing issues in the philosophy of personal identity and moral psychology. It serves both to advance important ongoing discussions of selfhood and to explore the light that, 200 years after his birth, Kierkegaard is still able to shed on contemporary problems. (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)

In a rigorous exploration of how secularism and identity emerged as conflicting concepts in the modern world, Akeel Bilgrami elaborates a notion of secular enchantment with a view to finding in secular modernity a locus of meaning and value, while addressing squarely the anxiety that all such notions are exercises in nostalgia.

This book is part of the growing field of practical approaches to philosophical questions relating to identity, agency and ethics--approaches which work across continental and analytical traditions and which Atkins justifies through an explication of how the structures of human embodiment necessitate a narrative model of selfhood, understanding, and ethics.

One conception of the Principle of Sufficient Reason maintains that every fact is metaphysically explained. There are different ways to challenge this version of the PSR; one type of challenge involves pinpointing a specific set of facts that resist metaphysical explanation. Certain identity and distinctness facts seem to constitute such a set. For example, we can imagine a scenario in which we have two qualitatively identical spheres, Castor and Pollux. Castor is distinct from Pollux but it is unclear what (...) could metaphysically explain this distinctness fact. In this paper, I argue that we should not treat identity and distinctness facts as metaphysically fundamental. As such, identity and distinctness facts do not challenge the PSR. We can metaphysically explain them. (shrink)

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

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)

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)

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)

This book is an examination of how the law understands human identity and the whole notion of 'human being'. On these two notions the law, usually unconsciously, builds the superstructure of 'human rights'. It explores how the law understands the concept of a human being, and hence a person who is entitled to human rights. This involves a discussion of the legal treatment of those of so-called "marginal personhood" (e.g. high functioning non-human animals; humans of limited intellectual capacity, and (...) fetuses). It also considers how we understand our identity as people, and hence how we fall into different legal categories: such as gender, religion and so on. The law makes a number of huge assumptions about some fundamental issues of human identity and authenticity - for instance that we can talk meaningfully about the entity that we call 'our self'. Until now it has rarely, if ever, identified those assumptions, let alone interrogated them. This failure has led to the law being philosophically dubious and sometimes demonstrably unfit for purpose. Its failure is increasingly hard to cover up. What should happen legally, for instance, when a disease such as dementia eliminates or radically transforms all the characteristics that most people regard as foundational to the 'self'? This book seeks to plug these gaps in the literature. (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)

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)

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)

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)

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)

The view that it is possible for someone to think at a time without existing at that time is not only perfectly coherent but in harmony with an attractive externalist view of the mental. Furthermore, it offers plausible solutions to various puzzles of personal identity.

This chapter aims to describe the way the generative experience is embodied in stories people tell about themselves, and to what extent the narrative approach has been used and has contributed to a better comprehension of generativity. To do so, firstly it examines the concept of narrative identity, that is, the way in which narratives have a key role in the definition of people, to the point of conceiving someone’s identity as a story that ties together their experience (...) and gives them continuity and purpose. Secondly, it describes how such narrative identities include stories related to experiences of generativity. In this respect, the chapter discusses research studying how people include generative themes in their personal stories, and finally it examines to what extent there is a cultural script of a generative life, what its features are, and how it relates with other master narratives concerning gender or age. (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)

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)

The paper discusses the problem of diachronic criteria of identity for historic localities. We argue that such criteria are needed not just for the sake of ontological clarity but also are indispensable for database management and maintenance. Our survey of the current research in database management and engineering ontology literature found no satisfactory candidates thereof. Therefore we attempt to search for such criteria in the historic-geographical scholarship by exposing the ontological assumptions the researchers made there and by stating them (...) explicitly. This attempt consisted of us presenting a number of brief scenarios taken from the historical studies whereby localities are claimed to maintain their identity through certain types of change or to be destroyed due to other types of change. Generalising these cases we provide a tentative formulation of the criterion and discuss its limitations. (shrink)

Dominic Wilkinson’s defence of identity-relative paternalism raises many important issues that are well worth considering. In this short paper, I will argue that there could be two important differences between the first-party and third-party cases that Wilkinson discusses, namely, a difference in associative duties and how the decision relates to the decision maker’s own autonomous life. This could mean that identity-relative paternalism is impermissible in a greater number of cases than he suggests.

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)

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.

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.