(2) If it were possible to analyze the atmosphere, water, and soil of Mars, and should such analysis reveal a composition similar to that of the earth, it would illustrate well not only the method of analysis but also its superiority over the other methods of investigation.
(3) The physician, in diagnosing a “case,” observes that the symptoms resemble those of typhoid; but to be positive of the truth of his diagnosis, he takes a blood test. Noting the resemblances is induction by analogy; but the blood test involves induction by analysis.
Induction by analysis concerns hypothesis, observation,and experiment, including Mill’s experimental methods. These topics will receive due attention in the chapters which follow. It will be sufficient to close this discussion with a brief treatment of perfect induction, and traduction.
14. PERFECT INDUCTION.
As has been indicated under simple enumeration, a perfect induction is one in which the premises enumerate all the instances denoted by the conclusion.
ILLUSTRATIONS:
(1) A, B, C, D, and E are all Reactionaries,
(All) The members of the committee are A, B, C, D, and E,
∴ (All) The members of the committee are Reactionaries.
(2) John, James, Albert, and Peter all have perfect eyesight,