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The goal of this dissertation is to offer a practice-based account of intentionality. My aim is to examine what sort of practices agents have to engage in so as to count as talking and thinking about the way the world is – that is, what sort of practices count as representational. Representational practices answer to the way the world is: what is correct within such practices depends on the way things are, rather than (only) on the attitudes of agents. An account of representation must explain how such objective standards of correctness are introduced in human practices: one must explain how the world gets to have a say in what is correct in human discursive practices. Roughly, my proposal is that human discursive practices become responsive to the way things are by virtue of involving practical interactions with the world. The outcomes of these interactions depend on the way the world is and the evaluation of such outcomes contributes to determining which moves within the practice count as correct. Due to our practical engagement with the environment, thus, the world gets to constrain discursive practices. In order to flesh out my proposal, I develop a practice-based characterization of intentional or representational content. On this sort of approach, expressing intentional contents is seen as a matter of playing a certain role in relevant practices, rather than as a matter of engaging in some word-world relation. The expression of content, thus, is explained in terms of use. In particular, I adopt an inferentialist perspective, according to which discursive moves express contents because of their role in practices of giving and asking for reasons. I investigate how practical engagement with the environment introduces friction with the world in these practices of giving and asking for reasons. One of the main conclusions reached in the dissertation is that defeasibility is an essential feature of objective representational practices – so that attributions of representational correctness are revisable in an open-ended way. The discussion of defeasible reasoning – and of the way in which defeasibility shapes human representational practices – is a central point of this dissertation.

Orientador: Balthazar Barbosa Filho / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-07-13T21:21:40Z (GMT). No. of bitstreams: 1 Loparic_AndreaMariaAltinodeCampos_D.pdf: 4680670 bytes, checksum: cd67073ce355c780cd6ade0827c462d4 (MD5) Previous issue date: 1988 / Resumo: Não informado / Abstract: Not informed. / Doutorado / Doutor em Lógica e Filosofia da Ciência

In this thesis I propose an improved theory of ontological commitment, one which is neutral on epistemology. Although Quine's quantificational criterion of ontological commitment has many advantages over its competitors, like its univocal treatment of being and existence, its clear account of ontological reduction and its capacity to accommodate implicit commitments, I argue that it has a fatal flaw: the inability to account for ontological commitment to individuals. Quine's choice of a first-order language of regimentation without constants is so entwined with his holist epistemology that imputations of existence cannot be made except to objects-qua-F, qua some wholly third-personal description. Commitments of those who believe that minds reach out directly to objects by means of acquaintance or introspection, encoded in language by constants, are ungrammatical in Quine's language. This breakdown of grammaticality, on my view, is an avoidable result of Quine's behaviourism and holist epistemology filtering into his choice of canonical language. I opt for a broader conception of ontological commitments as incurred by formalised theories with one or more semantic categories of categorematic objectual expressions, whose function is to stand for objects. I expand the language of regimentation at least to first-order logic with constants and identity. This preserves the attractive features of Quine's position. It retains its elegant treatment of reduction and implicit ontological commitments, and its capacity to explain away Meinongian confusions, without being beholden to global holism. My canonical language makes room for acquaintance and first-personal methods as sources of ontological commitment. It has the advantage of allowing theories like Quine's, which confine themselves to objects-qua-F, to be regimented as well as non-holist theories whose criteria of ontological commitment are 'to be is to be the referent of a name' or 'to be is to be the value of a constant or variable'.

H.E. Singleton. / "August 12, 1950." / Bibliography: p. 47. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B Dept. of the Army Project No. 3-99-10-022

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Equational reasoning with string diagrams provides an intuitive method for proving equations between morphisms in various forms of monoidal category. !-Graphs were introduced with the intention of reasoning with infinite families of string diagrams by allowing repetition of sub-diagrams. However, their combinatoric nature only allows commutative nodes. The aim of this thesis is to extend the !-graph formalism to remove the restriction of commutativity and replace the notion of equational reasoning with a natural deduction system based on first order logic. The first major contribution is the syntactic !-tensor formalism, which enriches Penrose's abstract tensor notation to allow repeated structure via !-boxes. This will allow us to work with many noncommutative theories such as bialgebras, Frobenius algebras, and Hopf algebras, which have applications in quantum information theory. A more subtle consequence of switching to !-tensors is the ability to definitionally extend a theory. We will demonstrate how noncommutativity allows us to define nodes which encapsulate entire diagrams, without inherently assuming the diagram is commutative. This is particularly useful for recursively defining arbitrary arity nodes from fixed arity nodes. For example, we can construct a !-tensor node representing the family of left associated trees of multiplications in a monoid. The ability to recursively define nodes goes hand in hand with proof by induction. This leads to the second major contribution of this thesis, which is !-Logic (!L). We extend previous attempts at equational reasoning to a fully fledged natural deduction system based on positive intuitionistic first order logic, with conjunction, implication, and universal quantification over !-boxes. The key component of !L is the principle of !-box induction. We demonstrate its application by proving how we can transition from fixed to arbitrary arity theories for monoids, antihomomorphisms, bialgebras, and various forms of Frobenius algebras. We also define a semantics for !L, which we use to prove its soundness. Finally, we reintroduce commutativity as an optional property of a morphism, along with another property called symmetry, which describes morphisms which are not affected by cyclic permutations of their edges. Implementing these notions in the !-tensor language allows us to more easily describe theories involving symmetric or commutative morphisms, which we then demonstrate for recursively defined Frobenius algebra nodes.

This thesis concerns the source of modal truth. I aim to answer the question: what is it in virtue of which there are truths concerning what must have been the case as a matter of necessity, or could have been the case but isn't. I begin by looking at a dilemma put forward by Simon Blackburn which attempts to show that any realist answer to this question must fail, and I conclude that either horn of his dilemma can be resisted. I then move on to clarify the nature of the propositions whose truth I am aiming to find the source of. I distinguish necessity de re from necessity de dicto, and argue for a counterpart theoretic treatment of necessity de re. As a result, I argue that there is no special problem concerning the source of de re modal facts. The problem is simply to account for what it is in virtue of which there are qualitative ways the world could have been, and qualitative ways it couldn't have been. I look at two ways to answer this question: by appealing to truthmakers in the actual world, or by appealing to non-actual ontology. I develop a theory of truthmakers, but argue that it is unlikely that there are truthmakers for modal truths among the ontology of the actual. I look at the main possibilist ontology, David Lewis' modal realism, but argue that warrant for that ontology is unobtainable, and that we shouldn't admit non-actual possibilia into our ontology. I end by sketching a quasi-conventionalist approach to modality which denies that there are modal facts, but nevertheless allows that we can speak truly when we use modal language.

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