“Nature” commonly means creation apart from any consideration of God or transcendent reality. So one could say nature is creation as if there were no creator. “Naturalism” is the doctrine or belief that the world and all that is in it are completely natural, that is, there is no creator external to nature. So naturalism is the doctrine or belief that creation exists independently of God, hence that God is either non-existent or irrelevant.
“Natural science” is the study of nature, which based on the above means the study of creation without a creator. Natural science is inherently naturalistic because the word “nature” sidesteps the reality of God. So methodological naturalism is an essential feature of natural science as commonly understood. The methods of natural science are limited to developing explanations without reference to the reality and activity of God. Teleology and ultimate purpose are excluded.
Natural science is a system of acquiring knowledge based on empiricism, experimentation, and methodological naturalism, as well as the body of knowledge so acquired. Criteria for a good scientific theory include: parsimony (simplicity), consistency (with evidence and with itself), verifiability (or falsifiability), and fruitfulness (leads to new discoveries).
“Social sciences” are the study of aspects of humanity, such as psychology (behavior), sociology (society), and political science (government). The term “natural science” is often limited to the study of non-human aspects of “nature” (such as physics, chemistry, and biology). But that is misleading because nowadays the social sciences approach humanity as a part of nature.
“Creation” is the world and all that is in it, understood as being distinct from God, created by God, and dependent upon God. Creation is thus the product of God’s activity of creation. “Creationism” is the doctrine or belief that the world and all that is in it were created by God ex nihilio.
“Creation science” is the scientific study of creation. Its methods are similar to those of natural science but it is always open to explanations that include the reality and activity of God. Creation science is a discipline, not a theory. It includes the study of various aspects of creation such as the physical, chemical, biological, psychological sociological, and political. Such studies may have the same names as corresponding natural sciences and so may be confused with each other.
While creation science acknowledges the reality and activity of God, it does not study God per se. That is the subject of theology. But the activity of God in and through the creation is studied by creation science because such activity is open to human experience. Since the activity of God is not subject to human manipulation, some methods of natural science may not apply to creation science.
Creation science begins with creation as a product of God’s activity. The initial state of the created world may be studied by creation science as much as any other state is. Whether or not the world was created is a matter for philosophy and theology, not science.
Empirical evidence and arguments for and against evolution, intelligent design, the gap theory, the day-age theory, old earth creation, and young earth creation can take place within creation science. Theological arguments relevant to these theories are part of theology, not creation science.
While creation science and natural science have much in common, there are several key differences: creation science is methodologically creationist, that is, it assumes the doctrine that the world and all that is in it were created by God ex nihilio. Creation science theories may include teleology or purpose. In fact, teleology may be a criterion for a good theory. Finally, creation science is subject to limits derived from theological sources: (1) moral constraints on experimentation and (2) boundary conditions on theories.
If the theological constraints and boundary conditions are based on the Bible, it may be called biblical creation science. Since this is by far the most common form of creation science, the term “creation science” is often understood as a short form of “biblical creation science”.
Natural theology is a form of theistic apologetics in which nature is shown to be a creation of God. This is the study of creation limited to what is available to the “natural man”, that is, those who are unaware of God or transcendental reality. Natural theology is not science but often there are arguments for or against it in science literature.