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Knowledge by deduction

Rumfitt, Ian (2008) Knowledge by deduction. Grazer Philosophische Studien/International Journal for Analytic Philosophy 77 , pp. 61-84. ISSN 0165-9227.

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It seems beyond doubt that a thinker can come to know a conclusion by deducing it from premisses that he knows already, but philosophers have found it puzzling how a thinker could acquire knowledge in this way. Assuming a broadly externalist conception of knowledge, I explain why judgements competently deduced from known premisses are themselves knowledgeable. Assuming an exclusionary conception of judgeable content, I further explain how such judgements can be informative. (According to the exclusionary conception, which I develop from some remarks in Ramsey, a judgement's content is given by the hitherto live possibilities that it excludes or rules out.) I propose that the value of logic lies in its allowing us to combine different sources of knowledge, so that we can learn things that we could not learn from those sources individually. I conclude by arguing that while single-conclusion logics possess that value, multiple-conclusion logics do not.

Item Type: Article
School or Research Centre: Birkbeck Schools and Research Centres > School of Social Sciences, History and Philosophy > Philosophy
Depositing User: Administrator
Date Deposited: 24 Nov 2010 12:32
Last Modified: 06 Sep 2013 16:08

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