Observe that though these canons hold for all the Figures, the Figure must be known, in all combinations containing A or O, before we can settle a question of validity by Canons II. and III., because the distribution of terms in A and O depends on their order in predication.
Take AEE. In Fig. I.—
All M is in P
No S is in M
No S is in P—
the conclusion is invalid as involving an illicit process of the Major. P is distributed in the conclusion and not in the premisses.
In Fig. II. AEE—
All P is in M
No S is in M
No S is in P—