Pluralism
"Pluralism" denotes any metaphysical theory which claims that reality consists of a multiplicity of distinct, fundamental entities. The term was first used by Christian Wolff (1679-1754), and later popularized by William James in The Will to Believe. Pluralism is distinguished from both monism, the view that one kind of thing exists, and dualism, the view that two kinds of things exist. There are weak and strong forms of pluralism theories. The weak form holds that there are many distinct individual things, whereas the strong form holds that there are many distinct kind of things. Theories dealing with the number of entities are referred to as substantival, and theories dealing with the type of entities are referred to as attributive.
Pluralism
Isaiah Berlin on pluralism
Evolution: The Pleasures of Pluralism 
STEPHEN JAY GOULD
Leibniz's Cultural Pluralism And Natural Law
Philosophical Pluralism: The Promise of Fragmentation
Monism, Dualism, Pluralism
'Utopian Pluralism': A Systematic Approach to the Analysis of Pluralism in the Debate about Thomas More's Utopia
The Middle Colonies as the Birthplace of American Religious Pluralism
Conceptual Pluralism
