Posterior Analytics (Bouchier)/Book I/Chapter XXVII

Chapter XXVII: What science is more certain and prior, and what less certain and inferior

 * The highest science is that which gives both the fact and the cause. The science which gives the cause only is superior to that which gives the fact only. One science may also be superior to another because it has immaterial objects or simpler principles.

A science is more exact than and prior to another when it gives the fact and the cause at the same time, and when there are not separate sciences for each. Further a science which has no material object is more exact than and prior to one which has (as in the case of arithmetic as contrasted with harmonics). Lastly a science with simpler principles is superior to one which requires a greater number. What I mean by this may be illustrated by the following example. Point is a substance in position, Unit a substance without position. Hence ‘point’ is possessed of additional qualities or principles.