Naturalism is the belief that everything in the cosmos is a component or product of the physical stuff of nature. There is no such thing as the supernatural, including souls, spirits, and God. Everything can (eventually) be explained using the hard sciences—biology, chemistry, and especially physics. Softer "sciences," such as psychology, sociology, and anthropology, can be reduced to the harder sciences. If there is such a thing as the supernatural, it does not affect the natural world in any noticeable manner.
What is Naturalism?
Philosophical naturalism (also known as metaphysical or ontological naturalism) is a belief system about the nature of the universe. The philosophy of naturalism is a gradient, but there are generally two different types.
Idealistic Naturalism - Idealistic naturalists believe that everything can be explained as a product of a combination of physical facts and physical laws. Everything is brought about by physical phenomenon, and nothing occurs that wasn't pre-determined according to nature. There is no free will, purpose, soul, God, or emotion, and there is no enduring self beyond physical death. The concept of free will is simply a result of the chaos theory; we are bombarded daily with so many inputs that we only think we make choices when we are actually acting according to circumstances too many to process. Qualia, or the experiences of life such as pain, preference, desire, or emotion, also do not exist. They are merely physiological responses to outside stimuli. Idealistic naturalists also believe that everything we think we feel has a corresponding neurological basis that will one day be interpreted—mapped out on an MRI. The phenomenon we call consciousness is merely the complexity of our physical matter.
The most obvious argument against idealistic naturalism is the sense of self. Idealistic naturalists deny that we have an independent, subjective, first-person view of ourselves and our experiences. Idealistic naturalism cannot explain the perception that we feel pain and anger, or recognize beauty, why we respond to our own name or use the term "I." This, in addition to the assertion that life has no meaning, makes idealistic naturalism a hard sell. And, ironically, the more idealistic naturalists push their view, the more they demonstrate their philosophy is a belief—something they deny exists. They turn the assertion that there is no supernatural into a religion.
Broad Naturalism - Broad naturalists also deny God and the human soul, but they admit that consciousness, mental thought, and value (both in preferences and morality) do exist. Such things do not belong in the spiritual realm; instead, they are emergent physical states of an extremely complex neurology. In response to the horrifying consideration that every action is pre-determined, broad naturalists rely on evolution. "Survival of the fittest" teaches that everything that has survived has done so because it was best able to survive. Similarly, values, ethics—even emotion and personal preferences—are all driven by our genes' built-in impetus to survive and pass on genetic traits. There are adaptations; some naturalists believe the desire to pass on genes is rooted in a genetic people-group, not individual genes. Others see "survival of the fittest" as a wholly selfish mechanism that created the concept of ethics to justify any behavior, such as altruism and suicide, that contradicts the violence of survival.
Proponents of broad naturalism have yet to determine where this consciousness exists in the physical world or how even a complex physical mechanism could result in something as subjective as thought. And although they do allow for "purpose" in human interaction, purpose that is driven by the survival of our DNA is not truly free will.
Obviously, the Bible refutes any degree of philosophical naturalism. As early as Genesis 1:2, the Spirit of God is mentioned. Genesis 1 goes on to say that humans were created in the image of God. God is spirit with no physical form, so the only way humanity can reflect God's image is if humans also possess a supernatural soul. The "image of God" also encompasses thought, personality, preference, and free will. First Thessalonians 5:23 not only mentions the soul of man, it distinguishes it from man's spirit. And Jesus Himself, when reassuring the thief of the cross, insisted on the continuation of a soul and a person beyond physical death (Luke 23:42-43). Philosophical naturalism is the attempt to deny the existence of God at the expense of the human self (Psalm 53:1).
In addition to naturalism as a philosophical worldview, it can also be a method of learning and exploration. Methodological naturalism is a system of scientific study wherein nature is assumed to have a natural basis. Divine intervention (miracles) is not taken into account in the investigation of natural phenomenon. Theistic scientists—who believe in God and the human soul—may be influenced by their theism in regard to ethics and priorities, but they still use the methodological naturalism of the scientific method in their practice of science. As the supernatural is beyond our abilities of description, explanation, and prediction, scientists believe the possibility of the supernatural should not influence the scientific work of description, explanation, and prediction.
In regards to methodological naturalism, there is merit in attempting to discover God's creation through the laws He has put into place. But, as God has created the cosmos, it also makes sense to take His work and His character into consideration. The Bible has specific things to say about geology and cosmology. Job 38 clearly shows that we cannot understand our world outside of the influence of God. Although a thorough scientific study will eventually bring us back to God's written account, it would save time if we'd just believe Him in the first place. Endeavoring to use science to explain and describe our world is a noble undertaking. But when scientists go so far as to deny a basic sense of self or even a sense of pain, it's an indication their desire for pure science has developed into a religion.
What does natural law teach?
What is atheism?
What is agnosticism?
Can the existence of God be proven?
What does it mean that humanity is created in the image of God?
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