I here develop a specific version of the deflationary theory of truth. I adopt a terminology on which deflationism holds that an exhaustive account of truth is given by the equivalence between truth-ascriptions and de-nominalised (or disquoted) sentences. An adequate truth-theory, it is argued, must be finite, non-circular, and give a unified account of all occurrences of “true”. I also argue that it must descriptively capture the ordinary meaning of “true”, which is plausibly taken to be unambiguous. Ch. 2 is a critical historical survey of deflationary theories, where notably disquotationalism is found untenable as a descriptive theory of “true”. In Ch. 3, I aim to show that deflationism cannot be finitely and non-circularly formulated by using “true”, and so must only mention it. Hence, it must be a theory specifically about the word “true” (and its foreign counterparts). To capture the ordinary notion, the theory must thus be an empirical, use-theoretic, semantic account of “true”. The task of explaining facts about truth now becomes that of showing that various sentences containing “true” are (unconditionally) assertible. In Ch. 4, I defend the claim (D) that every sentence of the form “That p is true” and the corresponding “p” are intersubstitutable (in a use-theoretic sense), and show how this claim provides a unified and simple account of a wide variety of occurrences of “true”. Disquotationalism then only has the advantage of avoiding propositions. But in Ch. 5, I note that (D) is not committed to propositions. Use-theoretic semantics is then argued to serve nominalism better than truth-theoretic ditto. In particular, it can avoid propositions while sustaining a natural syntactic treatment of “that”-clauses as singular terms and of “Everything he says is true”, as any other quantification. Finally, Horwich’s problem of deriving universal truth-claims is given a solution by recourse to an assertibilist semantics of the universal quantifier.

La thèse vise à montrer que la cohérence de l’interprétation instrumentaliste de la mécaniquequantique (sur laquelle les reconstructions logiques de la théorie, d’inspiration pragmatiste, s’appuient) ne peut pas être défendue sans remettre en cause la sémantique extensionnelle utilisée en logique classique. J’examine en particulier les arguments misen avant par Niels Bohr, en montrant que son analyse physique du processus de mesureest insuffisante pour assurer la cohérence de l’interprétation conditionnelle des probabilités quantiques qu’il adopte. Au lieu d’essayer de ‘compléter’ l’approche de Bohrpar un compte rendu plus exhaustif des processus physiques (telle la décohérence) quijouent un rôle dans l’observation, je suggère que le problème de la mesure découle d’unethéorie de la signification inadéquate. Je discute l’intérêt et les limites de la critiquebohrienne des présupposés représentationalistes inhérents à la description classique desphénomènes, et je conclus en formulant l’hypothèse que l’adoption d’une sémantiqueinférentialiste permettrait d’envisager à la fois la dissolution du problème de la mesureet la justification a priori des traits structuraux des probabilités quantiques (comme étantl’expression des relations conceptuelles présupposées par tout langage qui doit incluredes énoncés objectifs). / The dissertation purports to show that the consistency of the instrumentalist interpretationof quantum mechanics (upon which the logico-operational reconstructions of thetheory rest) cannot be defended without relinquishing the extensional semantic frameworkof classical logic. I examine in particular Niels Bohr’s argument, arguing that hisphysical analysis of measurement is insufficient to establish the coherence of the conditionalconstrual of quantum probabilities that he advocates. Rather than attemptingto ‘complete’ Bohr’s approach by means of a more sophisticated and comprehensiveaccount of the physical processes involved in the act of observation (e.g., decoherence),I suggest that the measurement problem should be viewed as the outgrowth of an inadequatetheory of meaning. I discuss, and point out some limitations of, Bohr’s ownpioneering critique of the representational assumptions inherent to the classical accountof phenomena, and I conclude by suggesting that the endorsement of an inferentialistsemantic approach would not only contribute to defusing the measurement problem, butmight also enable the a priori justification of the structural features of quantum probability(in terms of the conceptual relations presupposed by any language which allowsfor objective assertions).

Background: Psychological perfectionism, from a clinical perspective, started to be a topic of interest for cognitive behavioural clinicians at the beginning of the 1950s. Whilst many studies have identified perfectionism as a pivotal motivator in different conditions of neurosis, the exact nature of its interactions remains unclear. In the research community there is still a debate as to whether there is such a thing as good perfectionism, and there remains no consensual theory of psychopathological perfectionism. Aims: The aim of the study was to investigate why the nature of the phenomena remains a contentious issue, and to develop a robust theory of psychopathological perfectionism, within a cognitive behavioural framework, which will find general acceptance. From the literature review this appears to be the first qualitative study to develop such a theory. Method: Substantive grounded theory was developed within a framework of methodical hermeneutics which, it is argued, is capable of generating formative theory. 20 volunteers who came forward in response to advertisements became participants in semi-structured interviews using a post classic qualitative methodology, from which emerging data became the basis of categories leading to the development of the theory, and functions of the phenomena. Results and Conclusions: The study sets out reasons why there remains an impasse amongst researchers and clinicians about the condition of psychopathological perfectionism. A parsimonious theory of pathological perfectionism has been developed, the constructs of which are just necessary and sufficient to describe the condition. The developed theory makes a contribution to theories proposed prior to 1990 and to contemporary research. However as with all theories it is necessarily provisional, so that its usefulness is in need of further research and development. Psychopathological perfectionism has only two constructs, namely a demand to achieve perfectionism in at least one idiosyncratic sphere, which is in response to a core schema of conditional worth. A number of symptoms or functions of psychopathological perfectionism have also been identified, and there are suggestions as to how the condition develops and is maintained to the detriment of the sufferer. The study synthesizes over fifty years of theory and research into the phenomena. The developed theory and its symptoms or functions have important implications for clinical interventions, training, and for further psychological and psychosocial research. These implications are discussed.

Logical pluralism from historical perspective - Abstract The plurality of logics is understood as a challenge to seek a deeper understanding of the na- ture and import of logic. Two basic approaches to demarcation of logic are considered, the model-theoretic and the proof-theoretic one. Investigation of the history which led to these two appraoches identifies the postion of logic in Kant's epistemology as crucial for the devel- opment. An analogical development from Kant's conception of geometry to the plurality of geometric theories leads to a holistic view both of geometry and of logic. It furthermore proves essential to understand the pragmatic import of logic. Given the problems tied to the attempts to demarcate logic, inferentialism and logical expressivism are arrived at as jointly provid- ing the most appropriate account. These approaches are developed into a conception which stresses, in line with the historical perspective of the work, the ability of logic to develop.