In this introduction we mention… the condition of true definition and true demonstration and their divisions in a program more concise than what we set out in our Touchstone for Speculation and Yardstick of Knowledge [respectively, Ghazâlî 1966 and Ghazâlî 1961]. This introduction is not part of the sum of the science of [juristic] principles, nor among the preliminaries particular to it; rather it is an introduction to all the sciences, and he who does not comprehend [logic] is not to be trusted at all in his sciences. (Ghazâlî  Mustasfâ [1322 AH] 10.15–17)