Quick Definition: All valid claims and phenomena are the product of nature
Metaphysical naturalism, also called ontological naturalism, philosophical naturalism and scientific materialism is a worldview which holds that there is nothing but natural elements, principles, and relations of the kind studied by the natural sciences, i.e., those required to understand our physical environment by mathematical modelling. In contrast, methodological naturalism is an assumption of naturalism as a methodology of science, for which metaphysical naturalism provides only one possible ontological foundation.
Metaphysical naturalism holds that all properties related to consciousness and the mind are reducible to, or supervene upon, nature. Broadly, the corresponding theological perspective is religious naturalism or spiritual naturalism. More specifically, metaphysical naturalism rejects the supernatural concepts and explanations that are part of many religions.