Reck, A.J., An historical sketch of pluralism, The Monist, Jul90, Vol. 73, Issue 3

Aristotle's metaphysics centers primarily on the reality of individual substances and secondarily on the reality of essences. (..) Aristotle provided the ontological basis for metaphysical pluralism - for the doctrine that the ultimate realities, whatever else they are, are many.
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Aristotle also laid the foundations for methodological pluralism. (..) He wedded formal logic and empirical fact, and he was aware of the plurality of empirical fields. (..) A deemed the law of contradition ('the same attribute cannot at the same time belong and not belong to the same subject and in the same respect') to be "the most certain of principles". (..) Whereas Aristotle's methodology for the natural sciences projected an inductive/deductive model, his approach to first philosophy, or metaphysics, was dialectical. (..) Just as Aristotle's philosophy of language and logic precludes the divorce of meaning from reference, his theory of the causes rules out the divorce of value from fact.
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Leibniz's metaphysical pluralism emphasizes that the ultimately real things are psychical entities, and that there are multitudes of these entities. At the same time Leibniz insisted that whatever change occurs must occur within the monads in accord with their own internal principles. (..) Leibniz ranks first among philosophers in suggesting the perspectival character of every view of reality or whatever.
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No American philosopher has made the case for pluralism more vigorously than William James, pragmatist, radical empiricist, pluralist. (..) arguments for "a distributive form of reality, the each-form" (..) seeiing evil as practical problem to be faced in action (pragmatic verification of pluralism in moral experience). (..) A metaphysical pluralist, he was nevertheless a methodological monist.
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Mortimer Adler, in a brilliant early book, Dialectic (1927), welcomed "controversial discourse as one of the actual occasions of the life of reason." (..) critical pluralism with its hope for a realm of discourse that somehow contains all types of criticism, as suggested in Elder Olsen's essay, "The Dialectical Foundations of Critical Pluralism" (1966)
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Stephen Pepper's contribution to metaphilosophy, World Hypotheses (1942), was offered precisely as a response in defense of metaphysics against the anti-metaphysical strictures of the logical positivists. (..) By means of the root-metaphor theory Pepper classified and described the principal types of world hypotheses: formism from the root metaphor of similarity of form, mechanism from the root metaphor of the machine, organicism from the root metaphor of the biological organism, and contextualism from the root metaphor of the act in its context. (..) later he proposed a fifth world hypothesis, his own; he called it "selectivism," and he identified the purposive act as its root metaphor.
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Criteria of aesthetic value: Let me review briefly each of the four theories. Mechanism in aesthetics, best represented by Walter Pater, George Santayana, and David Prall, defines "the field of aesthetic values" to be "things liked or disliked for themselves;" it locates values in "the feelings of pleasure and displeasure."[36] The critical standards of mechanistic aesthetics are "the intrinsic dimensions of pleasure and displeasure, namely, the number, duration, and intensity of them."[37] Contextualism in aesthetics, represented by John Dewey and Irwin Edman, defines the aesthetic field as "voluntary vivid intuitions of quality;"[38] and the contextualistic standard is: "The more vivid the experience and the more extensive and rich its quality, the greater its aesthetic value."[39] Organicism in aesthetics, represented by Schelling, Coleridge, Hegel, and Bosanquet, identifies value with integration, aesthetic value with "the integration of feelings."[40] The organicist standard consists in "the degree of integration and the amount of material integrated."[41] Formism in aesthetics, represented by Plato, Aristotle, the medieval scholastics, John Ruskin, and Hippolyte Taine, describes aesthetic value broadly as "conformity to natural norms,"[42] and more strictly as the field of "perceptions satisfying in themselves to the normal man."[43] Stressing conformity to a norm, formistic aesthetics centers on the normal man as a biological, psychological and social entity and makes of him "a sort of governor over the whole aesthetic field. It holds art to the healthy golden mean, to what is sane and sound."[44]
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Kenneth Burke, A Grammar of Motives (1945). "What is involved, when we say what people are doing and why they are doing it?" And he stipulated that five terms, constituting the pentad, would serve as the generating principle of his investigation: Act, Scene, Agent, Agency, Purpose. (..) Hobbes and Spinoza instantiating the scene; Berkeley, Leibmz. Kant, Hegel, the agent; Aristotle and Aquinas, the act; the pragmatists. agency; and the mystics, purpose. (..) In construing the act as central, Burke's philosophy emerges as a type of process metaphysics antithetical to the ontologies of Plato and Aristotle. (..) Once the substantive is eradicated, each of Aristotle's 4 causes corresponds to one of Burke's placements: the efficient cause to the agent: the formal cause to the agency, or means; the material cause to the scene; and the final cause to the purpose.
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Richard McKeon - systematic pluralism, analyzing and explaining philosophies by reference to the Aristotelian doctrine of the four causes - method (formal cause), principle (efficient cause), subject-matter (material cause), and purpose (final cause). (..) "Philosophy and Method," published in the Journal of Philosophy in 1951: Philosophical methods: dialectic (focus on conflicts and contradictions & endeavor to eliminate them), logistic (trace knowledge back to the elements of which it is composed and the processes by which it is related), inquiry (discover solutions of problems and advancement of knowledge) (..) later paper: Four inclusive main heads of philosophic semantics may be set up - Principles, Methods, Interpretations, and Selections - but the differentiation of methods, and the relations of the methods to principles, interpretations, and selections can be rendered precise only by reference to common problems and to the modes of philosophic inquiry. (..) "Differences of methods, principles, purposes, and subject-matters account at once for the richness of philosophic discussion and the impossibility of bringing it to an unambiguous termination."
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Criticism, when pluralistic, contributes to the transformation of human groupings into a community, optimistically progressing toward what Peirce called the unlimited community of inquirers and what Royce named the beloved community of interpreters. Pluralism in philosophy and in criticism is, therefore, indispensable if dogmatism and skepticism are to be avoided.