{"id":{"repo_id":"durham","oai_identifier":"oai:etheses.durham.ac.uk:860"},"canonical_url":"https://search.dev.ndltd.org/etd/durham/oai:etheses.durham.ac.uk:860","repository":{"repo_id":"durham","name":"Durham University","base_url":"http://etheses.dur.ac.uk/cgi/oai2"},"display":{"title":"Conceivability, Apriority and Modality","abstract":"I aim to understand whether apriority entails necessity, aposteriority entails contingency and conceivability entails possibility; that is, the relationship between, and the nature of, rationality and modality. The thesis is split into two parts: one on apriority and modality (chs. 2-4), and another on conceivability, apriority/aposteriority and modality (chs. 5 to 7). In Chapter 1, I discuss ‘two-dimensional modal semantics’, arguing that it is ill-equipped to provide a substantive account of rationality and modality, before setting out the basis of such an understanding. I begin the first part of the thesis (in Chapter 2) by outlining a preliminary account of the a priori: it is, strictly, not defeasible by empirical evidence; it involves a kind of necessity (‘rational necessity’); and it is (at least in its prima facie variant) fallible. In Chapter 3 I discuss the contingent a priori, arguing that genuine apriority entails necessity, before placing apriority qua ‘rational necessity’ (and ‘rational modality’ more widely) with respect to other kinds of modality (in Chapter 4). I conclude Part I of the thesis, by arguing that the a priori is not coextensive with, but is grounded in, metaphysical necessity. Part II of the thesis begins with a discussion of the necessary a posteriori (Chapter 5), where I argue that there are no genuine cases, thus aposteriority entails contingency and conceivability entails possibility. I then deal with Frege’s and Kripke’s puzzles (Chapter 6), which I claim (as with the necessary a posteriori) pose no genuine problem for conceivability-possibility reasoning. Finally (in Chapter 7), I offer a deeper account of rational modality together with a tentative account of metaphysical modality (and essence). I then conclude that genuine apriority qua rational necessity entails metaphysical necessity; similarly, strictly, aposteriority (rational contingency) entails metaphysical contingency and, (in)conceivability (rational (im)possibility) entails metaphysical (im)possibility.","abstract_html":"I aim to understand whether apriority entails necessity, aposteriority entails contingency and conceivability entails possibility; that is, the relationship between, and the nature of, rationality and modality. The thesis is split into two parts: one on apriority and modality (chs. 2-4), and another on conceivability, apriority/aposteriority and modality (chs. 5 to 7). In Chapter 1, I discuss ‘two-dimensional modal semantics’, arguing that it is ill-equipped to provide a substantive account of rationality and modality, before setting out the basis of such an understanding. I begin the first part of the thesis (in Chapter 2) by outlining a preliminary account of the a priori: it is, strictly, not defeasible by empirical evidence; it involves a kind of necessity (‘rational necessity’); and it is (at least in its prima facie variant) fallible. In Chapter 3 I discuss the contingent a priori, arguing that genuine apriority entails necessity, before placing apriority qua ‘rational necessity’ (and ‘rational modality’ more widely) with respect to other kinds of modality (in Chapter 4). I conclude Part I of the thesis, by arguing that the a priori is not coextensive with, but is grounded in, metaphysical necessity. Part II of the thesis begins with a discussion of the necessary a posteriori (Chapter 5), where I argue that there are no genuine cases, thus aposteriority entails contingency and conceivability entails possibility. I then deal with Frege’s and Kripke’s puzzles (Chapter 6), which I claim (as with the necessary a posteriori) pose no genuine problem for conceivability-possibility reasoning. Finally (in Chapter 7), I offer a deeper account of rational modality together with a tentative account of metaphysical modality (and essence). I then conclude that genuine apriority qua rational necessity entails metaphysical necessity; similarly, strictly, aposteriority (rational contingency) entails metaphysical contingency and, (in)conceivability (rational (im)possibility) entails metaphysical (im)possibility.","abstract_has_math":false,"creators":["Winstanley, Paul"],"institution":"Durham University","degree_name":"PhD","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011","date_published":"2011","updated_at":"2026-07-24T02:11:17Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Winstanley, Paul"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011"]},{"key":"dc:date.issued","label":"Date","values":["2011"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Philosophy, Department of"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Durham University"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://etheses.durham.ac.uk/id/eprint/860/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://etheses.durham.ac.uk/id/eprint/860/1/Corrected_Thesis_-_COMPILED-FINAL.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["I aim to understand whether apriority entails necessity, aposteriority entails contingency and conceivability entails possibility; that is, the relationship between, and the nature of, rationality and modality. The thesis is split into two parts: one on apriority and modality (chs. 2-4), and another on conceivability, apriority/aposteriority and modality (chs. 5 to 7). In Chapter 1, I discuss ‘two-dimensional modal semantics’, arguing that it is ill-equipped to provide a substantive account of rationality and modality, before setting out the basis of such an understanding. I begin the first part of the thesis (in Chapter 2) by outlining a preliminary account of the a priori: it is, strictly, not defeasible by empirical evidence; it involves a kind of necessity (‘rational necessity’); and it is (at least in its prima facie variant) fallible. In Chapter 3 I discuss the contingent a priori, arguing that genuine apriority entails necessity, before placing apriority qua ‘rational necessity’ (and ‘rational modality’ more widely) with respect to other kinds of modality (in Chapter 4). I conclude Part I of the thesis, by arguing that the a priori is not coextensive with, but is grounded in, metaphysical necessity. Part II of the thesis begins with a discussion of the necessary a posteriori (Chapter 5), where I argue that there are no genuine cases, thus aposteriority entails contingency and conceivability entails possibility. I then deal with Frege’s and Kripke’s puzzles (Chapter 6), which I claim (as with the necessary a posteriori) pose no genuine problem for conceivability-possibility reasoning. Finally (in Chapter 7), I offer a deeper account of rational modality together with a tentative account of metaphysical modality (and essence). I then conclude that genuine apriority qua rational necessity entails metaphysical necessity; similarly, strictly, aposteriority (rational contingency) entails metaphysical contingency and, (in)conceivability (rational (im)possibility) entails metaphysical (im)possibility."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["Conceivability, Apriority and Modality"]}]}],"canonical_facts":{"dc:creator":["Winstanley, Paul"],"dc:date":["2011"],"dc:date.issued":["2011"],"dc:description.abstract":["I aim to understand whether apriority entails necessity, aposteriority entails contingency and conceivability entails possibility; that is, the relationship between, and the nature of, rationality and modality. The thesis is split into two parts: one on apriority and modality (chs. 2-4), and another on conceivability, apriority/aposteriority and modality (chs. 5 to 7). In Chapter 1, I discuss ‘two-dimensional modal semantics’, arguing that it is ill-equipped to provide a substantive account of rationality and modality, before setting out the basis of such an understanding. I begin the first part of the thesis (in Chapter 2) by outlining a preliminary account of the a priori: it is, strictly, not defeasible by empirical evidence; it involves a kind of necessity (‘rational necessity’); and it is (at least in its prima facie variant) fallible. In Chapter 3 I discuss the contingent a priori, arguing that genuine apriority entails necessity, before placing apriority qua ‘rational necessity’ (and ‘rational modality’ more widely) with respect to other kinds of modality (in Chapter 4). I conclude Part I of the thesis, by arguing that the a priori is not coextensive with, but is grounded in, metaphysical necessity. Part II of the thesis begins with a discussion of the necessary a posteriori (Chapter 5), where I argue that there are no genuine cases, thus aposteriority entails contingency and conceivability entails possibility. I then deal with Frege’s and Kripke’s puzzles (Chapter 6), which I claim (as with the necessary a posteriori) pose no genuine problem for conceivability-possibility reasoning. Finally (in Chapter 7), I offer a deeper account of rational modality together with a tentative account of metaphysical modality (and essence). I then conclude that genuine apriority qua rational necessity entails metaphysical necessity; similarly, strictly, aposteriority (rational contingency) entails metaphysical contingency and, (in)conceivability (rational (im)possibility) entails metaphysical (im)possibility."],"dc:format":["text"],"dc:identifier.uri":["https://etheses.durham.ac.uk/id/eprint/860/1/Corrected_Thesis_-_COMPILED-FINAL.pdf"],"dc:publisher.department":["Philosophy, Department of"],"dc:publisher.institution":["Durham University"],"dc:relation.isreferencedby":["https://etheses.durham.ac.uk/id/eprint/860/"],"dc:title":["Conceivability, Apriority and Modality"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-24T02:11:17Z"}