Naturalism (philosophy)
In philosophy, naturalism is the idea that only natural laws and forces (as opposed to supernatural ones) operate in the universe. In its primary sense it is also known as ontological naturalism, metaphysical naturalism, pure naturalism, philosophical naturalism and antisupernaturalism. "Ontological" refers to ontology, the philosophical study of what exists. Philosophers often treat naturalism as equivalent to materialism. For example, philosopher Paul Kurtz argues that nature is best accounted for by reference to material principles.