Naturalism is a philosophical view that interprets philosophical problems as tractable through the methods of the empirical sciences or at least, without a distinctively a priori project of theorizing. It is the idea that only natural laws and forces operate in the universe, and that nature is in principle completely knowable. Naturalism is a broad term that is applied to many doctrines and positions in philosophy, and there are different interpretations of it. Here are some key points about naturalism in philosophy:

• Ontological naturalism: This is the primary sense of naturalism, which holds that only natural laws and forces operate in the universe, as opposed to supernatural ones).

• Methodological naturalism: This is the view that religious commitments have no relevance within science, and that science is a possible route to important truths about the human spirit.

• Philosophical naturalism: This is a tendency common to a number of philosophical and religious systems, which consists essentially in looking upon nature as the one original and fundamental source of all that exists, and in attempting to explain everything in terms of nature).

• Materialism: This is a type of naturalism that holds that everything that exists is material, and that mental states and processes are identical to physical states and processes.

• Realism: This is a type of naturalism that holds that the world exists independently of our perceptions and beliefs about it, and that there is a mind-independent reality that we can know through empirical investigation.

Naturalism is a positive term in philosophical circles, and only a minority of philosophers nowadays are happy to announce themselves as non-naturalists. While naturalism has often been equated with materialism, it is much broader in scope, and has no ontological preference.