Page:Philosophical Review Volume 13.djvu/16

2 versal propositions as premises that syllogism draws its conclusions. Thus both induction and syllogism start from knowledge that we already have; the former being evolved from the perceptions of sense, and the latter from the premises supplied by induction. These two processes, as Aristotle points out in the present work, are common to dialectic, rhetoric, and the sciences. The proper subject of the treatise, however, is the method of science, and hence the two former methods of "teaching and learning" are referred to merely in order to show that reflection follows the same path in all cases, bringing forward universal propositions derived by the mind from perception, and deducing conclusions from them. Aristotle therefore at once proceeds to ask what is the character of the data with which science starts, and how from them the truths which constitute it are derived.

The view just stated of the relation of science to induction is Aristotle's substitute for the of Plato. According to the doctrine suggested in the Meno, learning is not the acquisition of knowledge for the first time, but the recollection of what we already know. Aristotle, on the other hand, maintains that we have no knowledge whatever prior to sensible perception, no knowledge of the universal prior to induction, and no scientific truth prior to the deductions drawn from the premises supplied by induction. Thus the difficulty raised by Plato, that we either learn nothing, or only what we knew beforehand, is solved, when we see that we may know universal principles, and may yet be ignorant of the conclusions involved in them, until these are brought to light by the deductions of science. Nor can we accept the doctrine that the only truth which is possible for us is limited by the number of individual instances that have come under our observation; on the contrary, the principles from which science draws its conclusions are universal, and so also are the conclusions derived from them. From arithmetic we learn, not that all the 'twos' we have observed are 'even,' but that every possible 'two' must be 'even.' Nothing less than this will satisfy the demands of science. In other words, 'science' ,