The arte of logick Plainely taught in the English tongue, according to the best approued authors. Very necessary for all students in any profession, how to defend any argument against all subtill sophisters, and cauelling schismatikes, and how to confute their false syllogismes, and captious arguments. By M. Blundevile.

CHAP. IX.

Of the equiualencie and conuersion of modall propositions.

THe Schoolemen doe affirme, that modall propo∣sitions are easily made equiualent, by reason that they may be vttered foure manner of waies, that is to say, two manner of waies affirmatiuely, and two manner of waies negatiuely. The first way af∣firmatiuely, is, when no negatiue is added either to the subiect, or to the mood; as, for a man to be iust, it is pos∣sible, contingent, impossible, or necessarie. The second way af∣firmatiuely, is, when the negatiue is added to the verbe of the subiect, the mood remaining still affirmatiue; as, for a man not to be iust, it is possible, contingent, &c. The first way negatiuely, is, when the negatiue is only added to the mood; as, a man to be iust, it is not possible, contingent, &c. The second way negatiuely, is, when the negatiue is both added to the verbe of the subiect, and also to the mood; as, a man not to be iust, it is not possible, contingent, &c. which is all one and equiualent to this affirma∣tiue proposition, saying, that for a man to be iust, it is possible, contingent, &c. for two negatiues, as well in the Latine tongue, as in ours, do alwaies make an affirmatiue. Again, as touching the cōuersion of modal propositions, they say, that the disiunct being like to an absolute or simple proposition, may be conuerted both simply and per accidens; but the coniunct suffereth no conuersion: & though the Schoolemen do set down diuers & manifold rules, and haue inuented these 4. words of Art, that is, PURPUREA, ILIACE, AM ABIMUS, EDENTULI, attributing as wel to the vowels, as to the consonants thereof, certaine significations, for the better vnderstanding & bearing in memorie the equiua∣lencies & conuersions of the said modal propositions: yet because in mine opinion they are more meet to breed preposterous, intri∣cate & barbarous speeches, then to serue to any other good pur∣pose, I thinke it better to passe them ouer with silence, then to trouble your memorie therwith: wherfore leauing them as things superfluous, I minde now to treat of an hypotheticall or cōpound proposition, & of al the necessarie accidents therunto belonging.