W.K. Clifford on Insufficient Evidence"The Ethics of Belief" in the The Ethics of Belief and Other Essays (Prometheus Books: 1999, orig. 1877), p. 96.
We may believe what goes beyond our experience, only when it is inferred from that experience by the assumption that what we do not know is like what we know. ¶ We may believe the statement of another person, when there is a reasonable ground for supposing that he knows the matter of which he speaks, and that he is speaking the truth so far as he knows it. ¶ It is wrong in all cases to believe on insufficient evidence; and where it is presumption to doubt and to investigate, there it is worse than presumption to believe.