Naturalism is a philosophical worldview that asserts that everything that exists, and every phenomenon that occurs, is a product of natural laws and processes. It contends that the universe operates without the need for supernatural explanations or interventions. In essence, naturalism posits that the natural world, as observed through science, is all there is. This perspective has deep roots in both philosophy and science, offering a framework for understanding reality that relies heavily on empirical evidence and reasoned inquiry.

At its core, naturalism rejects supernatural forces, divine beings, or metaphysical entities as explanations for natural phenomena. Instead, it emphasizes that everything in the universe, from the smallest particles to the vastness of the cosmos, can be understood in terms of physical, biological, and chemical laws. Naturalism also suggests that humans, as part of the natural world, are subject to the same laws governing the rest of the universe. This view aligns closely with the scientific method, which is built upon observation, experimentation, and the continual refinement of theories based on evidence.

In defining naturalism, it is essential to recognize its distinction from other philosophical frameworks. Unlike idealism, which asserts that reality is primarily mental or spiritual, naturalism asserts the primacy of the material world. Similarly, it differs from supernaturalism, which attributes the workings of the universe to forces beyond natural laws, such as gods or spirits. Naturalism's embrace of the empirical allows it to form the foundation for scientific inquiry, fostering advancements in fields ranging from physics and biology to psychology and medicine.