The main feature of NF/NFU is the notion of stratification, which sets it apart from other set theories. We define stratification and prove constructively that every stratified formula has the (unique) least assignment of types. The basic notion of stratification is concerned only with variables, but we extend it to abstraction terms in order to simplify further development. We reflect on nested abstraction terms, proving that they get the expected types. These extensions enable us to check whether some complex formula (...) is stratified without rewriting it in the basic language. We also introduce natural numbers and a variant of the axiom of infinity, in order to precisely introduce type level ordered pairs, which are crucial in simplifying the definitions in the last part of the article. Using these notions we can easily define the sets of ordinal and cardinal numbers, which we show at the end of the article. The same approach can be readily applied to NF. (shrink)

Community engagement is increasingly promoted as a marker of good, ethical practice in the context of international collaborative research in low-income countries. There is, however, no widely agreed definition of community engagement or of approaches adopted. Justifications given for its use also vary. Community engagement is, for example, variously seen to be of value in: the development of more effective and appropriate consent processes; improved understanding of the aims and forms of research; higher recruitment rates; the identification of important ethical (...) issues; the building of better relationships between the community and researchers; the obtaining of community permission to approach potential research participants; and, the provision of better health care. Despite these diverse and potentially competing claims made for the importance of community engagement, there is very little published evidence on effective models of engagement or their evaluation. (shrink)

In this paper, we rigorously prove the existence of type-level ordered pairs in Quine’s New Foundations with atoms, augmented by the axiom of infinity and the axiom of choice (NFU + Inf + AC). The proof uses the cardinal squaring principle; more precisely, its instance for the (infinite) universe (VCSP), which is a theorem of NFU + Inf + AC. Therefore, we have a justification for proposing a new axiomatic extension of NFU, in order to obtain type-level ordered pairs almost (...) from the beginning. This axiomatic extension is NFU + Inf + AC + VCSP, which is equivalent to NFU + Inf + AC, but easier to reason about. (shrink)

Charles Péguy (1873–1914) was a French religious poet, philosophical essayist, publisher, social activist, Dreyfusard, and Catholic convert. There has recently been a renewed recognition of Péguy in France as a thinker of unique significance, a reconsideration inspired in large part by Gilles Deleuze’s Différence et répétition, which ranked him with Nietzsche and Kierkegaard. In the English-speaking world, however, access to Péguy has been hindered by a scarcity of translations of his work. This first complete translation of one of his most (...) important prose works, with accompanying interpretive introduction and notes, will introduce English-speaking readers to a new voice, which speaks in a powerful and original way to a modern West in a condition of cultural and spiritual crisis. The immediate circumstance of the writing of this last prose essay, unfinished at the time of Péguy’s early death, was the placing of Henri Bergson’s philosophical works on the Catholic Index, and Péguy’s undertaking to defend his former teacher from his critics, both Catholic and secular. But the subject of Bergson is also a springboard for the exploration of the perennial themes—philosophical, theological, and literary—most central to Péguy’s thought. (shrink)

This paper offers a philosophical analysis of the connection between mental disorder and suicide risk. In contemporary psychiatry, it is commonly suggested that this connection is a causal connection that has been established through empirical discovery. Herein, I examine the extent to which this claim can be sustained. I argue that the connection between mental disorder and increased suicide risk is not wholly causal but is partly conceptual. This in part relates to the way suicidality is built into the definitions (...) of some psychiatric diagnoses. It also relates to the broader normative assumption that suicidal behavior is by definition mentally disordered behavior. The above has significant epistemological implications, which I explore. I propose that the claim that suicide is connected with mental disorder cannot be justified solely by appealing to empirical evidence but also warrants a justification on conceptual and normative grounds. (shrink)

Medical assistance in dying, which includes voluntary euthanasia and assisted suicide, is legally permissible in a number of jurisdictions, including the Netherlands, Belgium, Switzerland and Canada. Although medical assistance in dying is most commonly provided for suffering associated with terminal somatic illness, some jurisdictions have also offered it for severe and irremediable psychiatric illness. Meanwhile, recent work in the philosophy of psychiatry has led to a renewed understanding of psychiatric illness that emphasises the role of the relation between the person (...) and the external environment in the constitution of mental disorder. In this paper, I argue that this externalist approach to mental disorder highlights an ethical challenge to the practice of medical assistance in dying for psychiatric illness. At the level of the clinical assessment, externalism draws attention to potential social and environmental interventions that might have otherwise been overlooked by the standard approach to mental disorder, which may confound the judgement that there is no further reasonable alternative that could alleviate the person’s suffering. At the level of the wider society, externalism underscores how social prejudices and structural barriers that contribute to psychiatric illness constrain the affordances available to people and result in them seeking medical assistance in dying when they otherwise might not have had under better social conditions. (shrink)

In The Biopsychosocial Model of Health and Disease, Derek Bolton and Grant Gillett argue that a defensible updated version of the biopsychosocial model requires a metaphysically adequate account of disease causation that can accommodate biological, psychological, and social factors. This present paper offers a philosophical critique of their account of biopsychosocial causation. I argue that their account relies on claims about the normativity and the semantic content of biological information that are metaphysically contentious. Moreover, I suggest that these claims are (...) unnecessary for a defence of biopsychosocial causation, as the roles of multiple and diverse factors in disease causation can be readily accommodated by a more widely accepted and less metaphysically contentious account of causation. I then raise the more general concern that they are misdiagnosing the problem with the traditional version of the biopsychosocial model. The challenge when developing an explanatorily valuable version of the biopsychosocial model, I argue, is not so much providing an adequate account of biopsychosocial causation, but providing an adequate account of causal selection. Finally, I consider how this problem may be solved to arrive at a more explanatorily valuable and clinically useful version of the biopsychosocial model. (shrink)

This paper introduces a new theory of constant regions, which generalizes that of interstices, in nonstandard models of arithmetic. In particular, we show that two homogeneity notions introduced by Richard Kaye and the author, namely, constantness and pregenericity, are equivalent. This led to some new characterizations of generic cuts in terms of existential closedness.

A possibility of defining logical constants within abstract logical frameworks is discussed, in relation to abstract definition of logical consequence. We propose using duals as a general method of applying the idea of invariance under replacement as a criterion for logicality.

Claims about whether or not infertility is a disease are sometimes invoked to defend or criticize the provision of state-funded treatment for infertility. In this paper, I suggest that this strategy is problematic. By exploring infertility through key approaches to disease in the philosophy of medicine, I show that there are deep theoretical disagreements regarding what subtypes of infertility qualify as diseases. Given that infertility's disease status remains unclear, one cannot uncontroversially justify or undermine its claim to medical treatment by (...) claiming that it is or is not a disease. Instead of focusing on disease status, a preferable strategy to approach the debate about state-funded treatment is to explicitly address the specific ethical considerations raised by infertility. I show how this alternative strategy can be supported by a recent theoretical framework in the philosophy of medicine, which avoids the problems associated with the concepts of health and disease. (shrink)

It has been suggested that community advisory boards can play a role in minimising exploitation in international research. To get a better idea of what this requires and whether it might be achievable, the paper first describes core elements that we suggest must be in place for a CAB to reduce the potential for exploitation. The paper then examines a CAB established by the Shoklo Malaria Research Unit under conditions common in resource-poor settings – namely, where individuals join with a (...) very limited understanding of disease and medical research and where an existing organisational structure is not relied upon to serve as the CAB. Using the Tak Province Border Community Ethics Advisory Board as a case study, we assess the extent to which it might be able to take on a role minimising exploitation were it to decide to do so. We investigate whether, after two years in operation, T-CAB is capable of assessing clinical trials for exploitative features and addressing those found to have them. The findings show that, although T-CAB members have gained knowledge and developed capacities that are foundational for one-day taking on a role to reduce exploitation, their ability to critically evaluate studies for the presence of exploitative elements has not yet been strongly demonstrated. In light of this example, we argue that CABs may not be able to perform such a role for a number of years after initial formation, making it an unsuitable responsibility for many short-term CABs. (shrink)

Using a signaling framework, we argue that ethical behavior as evidenced by charitable donations is viewed more positively by investors when seen not to be based on self-serving motives but rather on authentic generosity that builds moral capital. The affirmed religiosity of CEOs may make their ethical position more credible, while their embeddedness within a family business suggests that CEOs are backed by powerful owners with long-time horizons and a desire to build moral capital with stakeholders. We find in a (...) study of market responses to 1572 corporate donations by S&P 1500 firms that financial markets react more positively to charitable initiatives from firms with religion-declared CEOs, but only if these are family businesses. (shrink)

The filtration method is often used to prove the finite model property of modal logics. We adapt this technique to the generalized Veltman semantics for interpretability logics. In order to preserve the defining properties of generalized Veltman models, we use bisimulations to define adequate filtrations. We give an alternative proof of the finite model property of interpretability logic with respect to Veltman models, and we prove the finite model property of the systems and with respect to generalized Veltman models.

Sobre la base de una línea interpretativa propiciada por la misma doctrina de Plotino, este trabajo pretende estudiar el problema que conlleva el fin último del alma humana en vista de su ascenso hacia el Uno-Bien. En varios pasajes de su obra, el filósofo sostiene que, conociendo el propio sí-mismo, se puede tomar contacto con un principio supremo, anterior incluso a la potencia intelectiva, en virtud de cuya visión es dable gozar de un amor sin medida. El remate en la (...) unificación no depende en última instancia del acierto racional, sino de concordar en el mismo centro con aquello de semejante al Uno-Bien que hay en el alma. Estas distinciones abonarían la posibilidad de una unión mística dentro del sistema plotiniano. Sin embargo, desde el punto de vista epistemológico, el estatuto místico es controvertido y plantea una serie dificultades teóricas que es necesario dilucidar. Para el análisis de los tópicos mentados se desarrolla una lectura a la vez hermenéutica y crítica tanto de las fuentes como de la bibliografía erudita. (shrink)

1. Die Illuminationsiehre des Michael Psellos und Joannes Italos.

In clinical medicine, a diagnosis can offer an explanation of a patient's symptoms by specifying the pathology that is causing them. Diagnoses in psychiatry are also sometimes presented in clinical texts as if they pick out pathological processes that cause sets of symptoms. However, current evidence suggests the possibility that many diagnostic categories in psychiatry are highly causally heterogeneous. For example, major depressive disorder may not be associated with a single type of underlying pathological process, but with a range of (...) different causal pathways, each involving complex interactions of various biological, psychological, and social factors. This paper explores the implications of causal heterogeneity for whether psychiatric diagnoses can be said to serve causal explanatory roles in clinical practice. I argue that while they may fall short of picking out a specific cause of the patient's symptoms, they can nonetheless supply different sorts of clinically relevant causal information. In particular, I suggest that some psychiatric diagnoses provide negative information that rules out certain causes, some provide approximate or disjunctive information about the range of possible causal processes, and some provide causal information about the relations between the symptoms themselves. (shrink)

It is often claimed in parts of the psychiatric literature that neuroscientific research into the biological basis of mental disorder undermines dualism in the philosophy of mind. This paper shows that such a claim does not apply to all forms of dualism. Focusing on Kenneth Kendler’s discussion of the mind–body problem in biological psychiatry, I argue that such criticism of dualism often conflates the psychological and phenomenal concepts of the mental. Moreover, it fails to acknowledge that there are different varieties (...) of dualism, and so overlooks the important metaphysical insights of contemporary dualist philosophers. I argue that while the neuroscientific research underpinning biological psychiatry challenges the traditional dualism of René Descartes, it does not pose any problem for the more modern dualism of David Chalmers. It is possible to take seriously the scientific claims of biological psychiatry while holding that this latter form of dualism is true. This has implications for the positioning of the mind–body problem in psychiatry. While the “easy” problem of explaining psychological processes is relevant to the aims of biological psychiatry, psychiatrists need not worry about the “hard” problem of consciousness. (shrink)

Diagnoses are central to the practice of medicine, where they serve a variety of functions for clinicians, patients, and society. They aid communication, explain symptoms, inform predictions, guide therapeutic interventions, legitimize sickness, and authorize access to resources. Insofar as psychiatry is a discipline whose practice is shaped by medical conventions, its diagnoses are sometimes presented as if they serve the same sorts of function as diagnoses in bodily medicine. However, there are philosophical problems that cast doubt on whether the functions (...) of psychiatric diagnoses can legitimately be considered to be equivalent to those of medical diagnoses. The aim of this chapter is to explicate some of these problems, particularly conceptual and epistemological problems pertaining to the roles of diagnoses as explanations. I begin with an overview of the various functions that medical diagnoses normally serve and suggest that many of these functions receive justificatory support from the explanatory roles of the diagnoses. I then present issues regarding the epistemic functions of psychiatric diagnoses and how these issues have featured in the arguments of prominent critics of psychiatry. (shrink)

This paper starts by investigating Ackermann's interpretation of finite set theory in the natural numbers. We give a formal version of this interpretation from Peano arithmetic (PA) to Zermelo-Fraenkel set theory with the infinity axiom negated (ZF−inf) and provide an inverse interpretation going the other way. In particular, we emphasize the precise axiomatization of our set theory that is required and point out the necessity of the axiom of transitive containment or (equivalently) the axiom scheme of ∈-induction. This clarifies the (...) nature of the equivalence of PA and ZF−inf and corrects some errors in the literature. We also survey the restrictions of the Ackermann interpretation and its inverse to subsystems of PA and ZF−inf, where full induction, replacement, or separation is not assumed. The paper concludes with a discussion on the problems one faces when the totality of exponentiation fails, or when the existence of unordered pairs or power sets is not guaranteed. (shrink)

Gender affirming hormone treatment is an important part of the care of trans adolescents which enables them to develop the secondary sexual characteristics congruent with their identified genders. There is an increasing amount of empirical evidence showing the benefits of gender affirming hormone treatment for psychological health and social well-being in this population. However, in several countries, access to gender affirming hormone treatment for trans adolescents has recently been severely restricted. While much of the opposition to gender affirming hormone treatment (...) for trans adolescents has in part been ideologically motivated, it also reflects a debate about whether there are harms that outweigh the benefits of the treatment. Accordingly, a systematic and comprehensive philosophical analysis of the ethics of gender affirming hormone treatment for trans adolescents is needed. Herein, I offer such an analysis that draws on the four principles of biomedical ethics by Tom Beauchamp and James Childress. Based on the considerations of beneficence, nonmaleficence, autonomy, and justice, I argue that the provision of access to gender affirming hormone treatment for consenting trans adolescents is ethically required and that the current restrictions to such treatment are ethically wrong. (shrink)

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

A class of Kripke models is modally definable if there is a set of modal formulas such that the class consists exactly of models on which every formula from that set is globally true. In this paper, a class is also considered definable if there is a set of formulas such that it consists exactly of models in which every formula from that set is satisfiable. The notion of modal definability is then generalized by combining these two. For thus obtained (...) types of modal definability on the level of Kripke models, we give characterization theorems in the usual form, in terms of algebraic closure conditions. As some consequences of these, various preservation results are presented. Also, some characterizations are strengthened by replacing closure under ultraproducts with closure under ultrapowers. (shrink)

We investigate how state involvement in the ownership of non-listed entrepreneurial firms affects pollution fees levied by national and provincial governments in China. While the national government sets minimum environmental standards, provincial governments can enact requirements that exceed these minimums, and they are largely responsible for enforcing even the national standards, so environmental levies can measure concessions that provinces make to encourage development and employment. Furthermore, state ownership is a good proxy for a firm’s political connections, which can influence the (...) relationship between the firm and the environmental authorities. We find that firms with state ownership pay lower environmental levies, which indicates that concessions are made for political or economic purposes. However, these concessions are conditional on the level of development of the province offering them, with better developed provinces providing fewer concessions. (shrink)

This volume links three different theoretical approaches that have a common focus on the relationship between biopolitics and bioethics. This collection of papers can be categorized into different domains that are representative of the contemporary usage of biopolitics as a concept. On the one hand, several chapters develop a clear and up-to-date understanding of the primary sources of the concept and related theories of Agamben, Negri or Foucault and approach the question of relevance within the field of bioethics. Another group (...) of papers apply the philosophical concepts and theories of biopolitics (biopower, Homo Sacer, biocitizenship) on very specific currently debated bioethical issues. Some scholars rely on the more mundane understanding of (bio)politics and investigate how its relationship with bioethics could be philosophically conceptualized. Additionally, this work also contains papers that follow a more legally oriented analysis on the effects of contemporary biopolitics on human rights and European law. The authors are philosophers, legal scholars or bioethicists. The major strength of this volume is to provide the reader with major insights and orientation in these different contemporary usages of the concept and theories of biopolitics, within the context of its various ethically relevant applications. (shrink)

In somatic medicine, diagnostic terms often refer to the disease processes that are the causes of patients' symptoms. The language used in some clinical textbooks and health information resources suggests that this is also sometimes assumed to be the case with diagnoses in psychiatry. However, this seems to be in tension with the ways in which psychiatric diagnoses are defined in diagnostic manuals, according to which they refer solely to clusters of symptoms. This paper explores how theories of reference in (...) the philosophy of language can help to resolve this tension. After the evaluation of descriptive and causal theories of reference, I put forward a conceptual framework based on two-dimensional semantics that allows the causal analysis of diagnostic terms in psychiatry, while taking seriously their descriptive definitions in diagnostic manuals. While the framework is presented as a solution to a problem regarding the semantics of psychiatric diagnoses, it can also accommodate the analysis of diagnostic terms in other medical disciplines. (shrink)

We can formalize judgments as logical formulas. Judgment aggregation deals with judgments of several agents, which need to be aggregated to a collective judgment. There are several logical formalizations of judgment aggregation. This paper focuses on a modal formalization which nicely expresses classical properties of judgment aggregation rules and famous results of social choice theory, like Arrow’s impossibility theorem. A natural deduction system for modal logic of judgment aggregation is presented in this paper. The system is sound and complete. As (...) an example of derivation, a formal proof of Arrow’s impossibility theorem is given. (shrink)

"Law and Economics has become an established field worldwide and it may be argued that it is one of the few examples of a successful interdisciplinary project. This book explores whether, or to what extent, that interdisciplinarity has indeed been a success. It provides insights on the foundations and methods, achievements and challenges of Law and Economics, at a time when both the continuing challenges to academic economics and the growth of empirical legal studies raise questions about the identity and (...) possible further developments of the project. Through a combination of reflections on long-term trends and detailed case studies on current developments, contributors to this volume analyse whether and in which sense Law and Economics is a successful interdisciplinary endeavour. Inspired by insights from the philosophy of social sciences, the book shows how concepts travel between legal scholarship and economics, how they change meanings when applied elsewhere, how economic theories and models inform, and transform, judicial practice, and addresses whether the transfers of knowledge between economics and law are symmetrical exchanges between the two disciplines"--. (shrink)

In the political discourse regarding gender identity, the concept of biological sex has been weaponised by gender critical commentators to oppose gender affirmation for trans people. Recently, these commentators have appealed to an essentialist model of sex based on anisogamy, or relative gamete size, to argue that one’s sex is an immutable characteristic. I argue that the gender critical argument is unsound. The diverse purposes of sex classification and the complex variability of people’s sexual characteristics show that an essentialist model (...) is untenable. I then consider how a more adequate theoretical framework from the philosophy of biology can accommodate this complexity and capture how sex is classified in relevant contexts. Further implications of the framework are explored which concern the vagueness, polysemy, and mutability of sex. These undercut the gender critical argument and show that the appeal to biological sex fails to undermine gender affirmation for trans people. (shrink)

Illusionism is the view that conscious experience is some sort of introspective illusion. According to illusionism, there is no conscious experience, but it merely seems like there is conscious experience. This would suggest that much phenomenological enquiry, including work on phenomenological psychopathology, rests on a mistake. Some philosophers have argued that illusionism is obviously false, because seeming is itself an experiential state, and so necessarily presupposes the reality of conscious experience. In response, the illusionist could suggest that the relevant sort (...) of seeming here is not an experiential state, but is a cognitive state, such as a judgement or a belief, which is fully amenable to a physical or functionalist analysis. Herein, I argue that this response is unsuccessful and fails to undermine the reality of conscious experience. Nonetheless, the response does raise the problem of how a judgement or belief about the character of a conscious experience, even if it is true, can be justified if the conscious experience has no causal role in the formation of the judgement or belief. This is not a new problem, but is a reiteration of an old problem that is known in the philosophy of mind literature as the paradox of phenomenal judgement. I consider how the paradox of phenomenal judgement can be resolved and how the judgement or belief about conscious experience can be justified with appeal to the notion of acquaintance. (shrink)

El objetivo de esta investigación ha sido mostrar la fecundidad de la metafisica blondeliana para iluminar y responder al carácter tensional de la vida de fe y de las afirmaciones escatológicas. El «ya» y el «todavía no» no son mas que uno en una relación «idénticaa la exigencia de un magis», «entre lo que queremos, porque tadavia no lo somos, y lo que queremos, porque lo habremos querido». No se trata de querer lo que somos sino de ser lo que (...) queremos. Para ello nos hemos servido de las figuras de «don, kénosis y comunión» como consumación del destino del ser humano dentro de la historia de relación entre Dios y el mundo finito. Mostramos cómo la comunión, tal como se configura en la metafisica blondeliana, responde a lo que hemos propuesto como consistencia escatológica, es decir una ciencia escatológica practicante y no a practicar. La comuniòn como consortium divinae vitae representa la aspiración a la que tiende todo lo creado, omnia intendunt assimilari Deo! Aspirar a ella postula la ineficacia de alcanzarla y, en consecuencia, la necesidad del don y la exigencia de uma kénosis, entrar en ella no significa pararse, sino entrar en la dinámica de su infinita fecundidad como un equilibrio en movimiento. (shrink)

Diagnoses in medicine are often taken to serve as explanations of patients’ symptoms and signs. This article examines how they do so. I begin by arguing that although some instances of diagnostic explanation can be formulated as covering law arguments, they are explanatory neither in virtue of their argumentative structures nor in virtue of general regularities between diagnoses and clinical presentations. I then consider the theory that medical diagnoses explain symptoms and signs by identifying their actual causes in particular cases. (...) While I take this to be largely correct, I argue that for a diagnosis to function as a satisfactory causal explanation of a patient’s symptoms and signs, it also needs to be supplemented by understanding the mechanisms by which the identified cause produces the symptoms and signs. This mechanistic understanding comes not from the diagnosis itself, but rather from the theoretical framework within which the physician operates. (shrink)

In the philosophical literature on consciousness and the mind-body problem, the conceivability argument against physicalism is usually taken to support a form of dualism between physicality and phenomenality. Usually, the discussion focuses on the qualitative character of experience, which is what the phenomenal feel of a given experience is like. By contrast, the subjective character of experience, or its individuation to a given first-person subject, tends to be set aside. The aim of this paper is to present a new and (...) more robust version of the conceivability argument for dualism that appeals to the subjective character of experience. Drawing on insights by philosophers in the phenomenological tradition, I conceptualise the first-person subjective character of experience as a transcendental condition of possibility for phenomenality that cannot be reduced to third-person facts about the physical world. Given this, the mind-body problem as it pertains to consciousness does not merely concern the inability of the set of physical facts about a brain state to capture the qualitative character of experience, but concerns the existential issue of why this brain state is accompanied by first-person subjectivity at all. This allows us to reconceive the conceivability argument in a way that presents a stronger case for dualism than the traditional version of the argument. (shrink)

This paper addresses a philosophical problem concerning the ontological status of age classification. For various purposes, people are commonly classified into categories such as “young adulthood”, “middle adulthood”, and “older adulthood”, which are defined chronologically. These age categories prima facie seem to qualify as natural kinds under a homeostatic property cluster account of natural kindhood, insofar as they capture certain biological, psychological, and social properties of people that tend to cluster together due to causal processes. However, this is challenged by (...) the observation that age categories are historically unstable. The properties that age categories are supposed to capture are affected by healthcare and cultural developments, such that people are staying biologically, psychologically, and socially young for longer. Furthermore, the act of classifying people into age categories can bring about changes in their behaviors, which in turn alter the biological, psychological, and social properties that the categories are supposed to capture. Accordingly, I propose that age categories are best understood as interactive kinds that are influenced in dynamic ways by looping effects. I consider some implications of these looping effects for our classificatory practices concerning age, including how different disciplines may need to review the ways they define and use age categories in their inductive inferences. (shrink)