By induction we gain no certain knowledge; but by observation, and the inverse use of deductive reasoning, we estimate the probability that an event which has occurred was preceded by conditions of specified character, or that such conditions will be followed by the event.... I have no objection to use the words cause and causation, provided they are never allowed to lead us to imagine that our knowledge of nature can attain to certainty.... We can never recur too often to the truth that our knowledge of the laws and future events of the external world are only probable.

pp. 257, 260 & 271 - The Principles of Science: A Treatise on Logic and Scientific Method (1874) Vol. 1