Mohammad Mohsen Haeri
Abstract
David Lewis was a reductivist and nominalist. He saw the majority of his philosophical works to be a campaign on behalf of Humean Supervenience; a doctrine according to which the distribution of perfectly natural properties (/relations) acts as a supervenience basis for all contingent truths; such as ...
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David Lewis was a reductivist and nominalist. He saw the majority of his philosophical works to be a campaign on behalf of Humean Supervenience; a doctrine according to which the distribution of perfectly natural properties (/relations) acts as a supervenience basis for all contingent truths; such as causation, counterfactuals, events, and laws. He also extends his reductivism to the domain of a necessary discourse like mathematics by trying to reconstruct second-order ZFC through mereology. A domain that he never addressed, though, was logic. The purpose of this article is to present a Lewisian interpretation of logic which similar to his own interpretation of mathematics, is based on mereology. On this interpretation, the relation of logical consequence is reduced to a mereological relation between singletons of possible worlds. Furthermore, the implications of this interpretation for the two main characteristics of logical consequence, i.e. necessity and formality, and also the consistency and completeness of logic are examined.
Mohammadmohsen Haeri; Davood Hosseini
Abstract
Logical realism, in a sense, is realism about the subject matter of logic. What is logic really about? Talk of logic is more or less synonymous with talk of the relation of logical consequence; the relation that holds between the premisses of an argument and its conclusion. However, in the history logic, ...
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Logical realism, in a sense, is realism about the subject matter of logic. What is logic really about? Talk of logic is more or less synonymous with talk of the relation of logical consequence; the relation that holds between the premisses of an argument and its conclusion. However, in the history logic, this has not always been the case. Before placing logical consequence at the heart of logic, the Frege-Russell view was dominant in the philosophical community; a view according to which logic is primarily about logical truths. In this paper, we argue that logic is about logical consequence and not logical truth. Then we list a couple of motivations for investigating a metaphysics of logic. Proponents of logical realism typically base their theories upon logical truths as logical facts. In this article, we aim to turn the emphasis from logical truths to logical consequence(s) as the primary object(s) of logical realism and give a general outline on how to be a realist about logical consequence.
