8. Methodological naturalism - in science, naturalism is assumed and attempts to explain the world are limited to only natural causes. The supernatural is excluded simply because it is neither falsifiable nor testable and would not yield practical results. Many scientists are theists of various beliefs and religious scientists can do good science by excluding their personal beliefs from their work. In contrast, consider ID which tries to find examples in nature that have no natural explanation (too complex to be explained or reduced). In this case, one wonders how this latest God-of-the-gaps view can be considered science at all since ultimately they are looking to bring the supernatural into what has been one of the most successful areas of knowledge formulation yet developed. Of course, this would doom methodological naturalism as a structure in science.
9. Metaphysical naturalism - the philosophical statement that the natural world is all that exists and there is no supernatural.
10. Agnostic - in common use, a person who believes that there is not enough or may never be enough definitive information to decide about the existence or non-existence of God. Unfortunately, this word's common usage has been somewhat corrupted as it's parts actually simply mean not knowing (a = not, gnosis = knowledge). Therefore, we are all agnositc since no one knows everything. The word was first coined in 1860 by Thomas H. Huxley, who became known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theories of natural selection and evolution.
11. Fact - verified information or knowledge about an occurrence that exists or an event that has occurred. Knowledge or information based on real occurrences. We often hear, "it's a scientific fact" when what is really being referred to are the findings from only a small research study or studies that may or may not have broad application, or statements that are really inferences. Coyne and Gould have defined a scientific fact as "an assertion for which there is so much evidence that it would be perverse to deny it".
12. Proof - evidence establishing a fact or truth. Proofs probably do not exist in the natural sciences. In mathematics proofs can be obtained from deductive reasoning, that a statement is true in all cases. In most of the sciences, evidences are gathered that can support or validate predictions or theories. The best we can do is make the probability of a concept or prediction so high that it would be unlikely to be ever false. But we don't have perfect knowledge and we have not been everywhere in the universe so it is unlikely that we can say with 100% certainty that something will always be true. Thus, a statement heard often, "It's scientifically proven that ..." really makes no sense. Although no one has seen the earth go around the sun, we have so many evidences and verified predictions that to reject this statement would not be rational, but it really has not been proved in the sense of the term.