Theists and atheists alike use ‘methodological naturalism’ when doing science, because scientific method depends on understanding and explaining the natural world in natural terms. It does not assume that God does not exist. Many Christians do not believe that the evidence supports Creationism despite believing in God, and instead believe that God is the one who sustains and upholds the natural order as understood by science.  Uniformitarianism is a necessary assumption for understanding the world. If the laws of nature changed on a whim, so that science worked one way on Tuesday and another on Wednesday, we would not be able to make observations and predictions that worked. But all our observations indicate that the world does operate consistently. The success of science in providing accurate models and explanations of the world shows that its presuppositions are correct.  Science cannot prove or disprove the existence of God, since that is a metaphysical question outside the scope of science. But science can show that evolution explains the origins of life, and there is no need to invoke a God of the Gaps to explain it. The supernatural is outside the scope of scientific enquiry, and therefore a matter of faith.