>Naturalism is a metaphysical theory that holds that all phenomena can be explained mechanistically in terms of natural (as opposed to supernatural) causes and laws. Naturalism posits that the universe is a vast «machine» or «organism,» devoid of general purpose and indifferent to human needs and desires.
The deistic founders of the United States of America were advocates of naturalism. Deism admits a transcendent creator of the universe but denies that the creator interferes with Nature. Hence, understanding God is unnecessary to understanding the world.
Pantheistic philosophies—such as that of the ancient Stoics, John Scotus Eriugena (Ireland, 9th century), Giordano Bruno (Italy, 16th century), and Spinoza (Holland, 17th century)—are naturalistic. In pantheism, God is the world.
Naturalism does not deny the existence of God, either as transcendent or immanent. However, naturalism makes God an unnecessary hypothesis and essentially superfluous to scientific investigation. Reference to moral or divine purposes has no place in scientific explanations. On the other hand, the scope of science is limited to explanation of empirical phenomena without reference to forces, powers, or influences that are supernatural.
The difference between naturalistic and supernaturalistic views in Western philosophy might best be understood by noting that the former favors mechanistic explanations, while the latter favors teleological ones. Mechanistic explanations are dysteleological, i.e., they make no reference to purposes or design, except metaphorically as in biology (e.g., the heart was designed to pump blood).
The difference between mechanistic and teleological views may best be understood by considering a few examples.
the sex drive
From a teleological point of view, the sex drive is designed to reproduce the species. The pleasure that accompanies sex is the main inducement to carry out the purpose of reproduction. If sex were generally painful, it would be avoided by most members of the species, and hence the species would likely become extinct. Some theologians maintain that to engage in sex for the purpose of reproduction is the only proper sexual motive. To frustrate the reproductive purpose of sex is to act contrary to divine purpose and is immoral. Birth control and homosexuality, therefore, are morally wrong because they are unnatural. (On this logic, taking a shot of insulin is immoral because it is unnatural.)
From a mechanistic point of view, the sexual urge is purposeless. It was not designed to motivate animals to reproduce. Rather, animals with a strong sexual drive reproduce and, other things being equal, flourish. A species whose members have a weak sexual drive would be unlikely to survive. According to this view, the purpose of sex can’t be frustrated, since sex, in general, has no purpose. (Of course, the desire to have sex with a particular person is purposive. That is the purpose: to have sex with a particular person, whatever gender that person might be.) Since nothing has been designed to fulfill a particular purpose, moral goodness and evil cannot be determined by their being natural or not. Some other ethical principle, such as utility, must be invoked. In any case, naturalism does not imply that all things are good since all things are natural in some sense. Even the artificial is natural since ultimately everything originates in the natural world.
From a teleological point of view, bee pollination of orchards is purposive and part of a design. To the mechanist, bees just do their thing and, as a result, orchards get pollinated. If no animals existed that do what bees do, orchards wouldn’t exist. The world would be a different place, but it would still be a world. Different mechanisms mean different worlds. The choice is not between this world or none at all, but this world or some other one.
To the teleological supernaturalist, pedophiles and sexual predators exist for some sort of divine purpose. To the mechanistic naturalist, child molesters and child murderers are purposeless. Their desires may be natural but that does not mean that they should be fulfilled. Both the supernaturalist and the naturalist may hold pedophiles and sexual predators accountable for their evil behavior, but not necessarily. There are some supernaturalists and some naturalists who are determinists and who do not hold anyone accountable for anything, except God or nature. The naturalist, however, need not feel any need to try to explain why such evil exists. Some naturalists might seek causal explanations that deny that evil acts are chosen behaviors by evil persons with evil desires. All naturalists might agree that the desires themselves are explicable entirely by causal mechanisms outside the scope of personal responsibility. But, not all would agree that acting on the desires is completely explicable without reference to the freedom and responsibility of the evildoer.
What is the purpose of evil?
The supernaturalist, with his moral and spiritual purposes inherent in every aspect of reality, must come up with some sort of explanation for the existence of evil. The branch of theology that tries to explain such things is called theodicy. In theodicy it is considered reasonable and acceptable to say of evil: «the ways of the Lord are mysterious, indeed.» Or, as God allegedly said to Job when he dared to ask «Why me?»: «Hath thou an arm like the Lord?» In short, «I’m God; I don’t have to explain myself to anybody.» Evil exists and since God is good you can be sure that there is a good reason for evil. Take it on faith.
teleology according to Spinoza
Spinoza maintained that teleological thinking represents the primitive thinking of our pre-scientific ancestors. The pursuit of «final causes» led nowhere in the quest to understand nature. Only when humankind gave up the anthropomorphic way of thinking—which understands the weather, geology, physics, and the like—in terms of divine purposes, could progress in knowledge of nature be made. History has proved Spinoza right. Teleological theories, such as supernaturalism, are scientifically superfluous.
On the other hand, Spinoza’s attack on teleology was complete: he did not believe that human behavior was to be explained differently from anything else in nature. Human behavior is to be explained in terms of mechanistic causes, just as the behavior of all natural phenomena are to be explained. Humans are no more free to change their behavior than falling stones are free to change their direction. And neither humans nor falling stones are responsible for their behavior or movements. However, Spinoza’s denial of free will is no more a necessary consequence of naturalism than is his pantheism. That is, neither determinism nor pantheism is entailed by naturalism.
Finally, a naturalistic worldview is one that has no supernatural or mystical element to it. The universe is all we can ever hope to know and there is no compelling reason to posit a supernatural world beyond and in addition to the natural world. The infusion of supernatural elements into human societies is itself a natural phenomenon that has a naturalistic origin and history. There may be elements or forces in nature that are not understood, but there is nothing that requires magical thinking or superstitious positing of transcendent beings to account for them. Even religions and philosophies that center around beliefs in the supernatural, as well as so-called mystical experiences, are themselves natural and originate without the assistance of anything supernatural. Even so-called miracles are explicable in terms of natural phenomena. And contrary to the propaganda spread by many supers regarding the necessity of a supernatural being to give commands in order for there to be actions that are right or wrong, most ethical systems that have evolved in human societies do not depend on reference to anything supernatural.