Page:Theory of Mind of Roger Bacon.djvu/12

 broadly the limitations of his problem. And it is this problem, set by his master Aristotle, which he means to further develop. Let us get succinctly before us, therefore, the Aristotelian treatment of the problem, to see how far he carried it, and wherein it offered opportunity for further development.

The problem of change forms for Aristotle one of the three great problems of his Metaphysics, and the leading theme of his Physics. And he was the first to treat it fully with reference to Matter and Form. Change is motion, and motion is the transition from the Potential to the Actual; it therefore implies the actual Form and the potential Matter.

In his analysis of Motion he finds three kinds, to wit, spatial and quantitative and qualitative. There are several kinds of change in position. Change in quantity is either increase or diminution; while change in quality is alteration. Generation and decay may be added as a fourth kind of change. In a sense all change may be reduced to change in position; yet change in quality is to be counted as a second source. The conditions for the process of change are as follows: contact between Agent and Patient, identity of Genus, and difference of Species. When Agent and Patient meet, the one is actually what the other is only potentially; and the change consists in the removal of the opposition, that is, the Agent makes the Patient like itself.

A careful examination of the Aristotelian conception reveals, that in three important respects it permitted further elaboration. First, in the circumscribing of the problem—the relation of change and motion, and of the various kinds to each other. Second, in the meaning and function of Form and Matter. Third, in the details of the process of assimilation. As regards the first, Bacon shows