It assumes the universe operates according to regularities and that through systematic investigation we can understand these regularities. The methodology of science emphasizes the logical testing of alternate explanations of natural phenomena against empirical data. Because science is limited to explaining the natural world by means of natural processes, it cannot use supernatural causation in its explanations. Similarly, science is precluded from making statements about supernatural forces, because these are outside its provenance. Science has increased our knowledge because of this insistence on the search for natural causes.
Theories are powerful tools.
Scientists seek to develop theories that are internally consistent and compatible with the evidence are firmly grounded in and based upon evidence have been tested against a diverse range of phenomena possess broad and demonstrable effectiveness in problem-solving explain a wide variety of phenomena. The body of scientific knowledge changes as new observations and discoveries are made. Theories and other explanations change. New theories emerge and other theories are modified or discarded. Throughout this process, theories are formulated and tested on the basis of evidence, internal consistency, and their explanatory power.