Naturalism is a worldview that asserts that the universe is a closed system in which matter and energy are the only realities. This perspective rules out the existence of any supernatural beings including God. According to naturalism, the world operates according to natural laws in which there are a series of cause and effects. Because the universe operates according to natural processes there are no miracles or events that have any supernatural cause. Thus, everything in the universe is subject to scientific study and verification. Naturalism would be consistent with materialism and monism in which all of reality is inherently connected to the physical realm. Naturalism disagrees with dualism and its assertion that reality is made up of two distinct substances—the material and the immaterial. This rejection of dualism means that naturalists do not believe that people have an immortal soul that can survive physical death. For naturalists, the present life of a person is the only life he or she will ever have. There are no past lives to due to reincarnation nor is there a future life in some state of bliss or torment.
Because naturalism rejects any concept of the supernatural this view is intrinsically linked with atheism, the belief that there is no God. Naturalism also usually leads to the rejection of moral absolutes since there is no divine being or law that determines standards for right and wrong. Thus, naturalism often leads to ethical relativism in which individuals and societies are free to determine their standards for right and wrong.
David Hume was a key figure in laying a philosophical basis for naturalism. He refuted the idea of miracles claiming that testimonies of miracles were most likely false reports. Charles Darwin’s theory of evolution was also important in that it offered a purely naturalistic explanation of origins. Naturalism is well-represented today and is the prevailing worldview in the academic and scientific communities of the West.