All scientific hypotheses must be constructed so that they can be tested, with a view to proving false those which are not correct. Any hypothesis which is not subject, at least in principle, to being rejected by observation or experiment is not a scientific hypothesis.
Science can investigate only the empirical, the natural world.
Thus, the supernatural is outside the realm of scientific studies. Therefore, a scientific hypothesis may not contain any reference to supernatural beings or activities. A scientist must be willing to submit all of his procedures, data and conclusions to critical examination by his fellow scientists or by anybody else who can offer intelligent criticisms of his work. Since the definition of science says nothing about beliefs, a scientist is free to believe or disbelieve whatever he pleases. The idea for a scientific hypothesis may come from any source, for example, by reasoning from things observed, by pure creative insight and imagination, from a comic book, a dream or the Bible.