We all know what we mean by science; science is 'organised common sense.' Her aim is the acquisition of reasoned and orderly knowledge. Presented with a collection of verified facts, it is the part of science to reduce them to order, and to account for their existence in accordance with her recognised theory of things. If the facts cannot be fitted into the theory, it must be expanded or altered; for we must admit that, if the facts are verified, there is need for change and expansion in the theory. The 'colligation' of facts demands hypotheses, and these may not, at the moment of their construction, be verifiable. The deflections of a planet from its apparently normal course may be accounted for by the hypothesis of the attraction of another heavenly body not yet discovered. The hypothesis is legitimate, for such bodies are known to exist, and to produce such effects. When the body is discovered, the hypothesis becomes a certainty. On the other hand, the hypothesis that some capricious and conscious agency pushed the planet into deflections would be illegitimate, for the existence of such a freakish agency is not demonstrated. Our hypotheses then must be consistent with our actual knowledge of nature and of[Pg 2] human nature, and our conjectured causes must be adequate to the production of the effects. Thus, science gradually acquires and organises new regions of knowledge.
