Chapter VIII, Continuation from Page 471.

conversion according to itself is perfect and of evident necessity; and thus this enthymeme which is conversion does not receive perfection from a syllogism. For if it were said that conversion perfecting an imperfect syllogism did not have necessity of itself but received it from another, that other would have to go off to infinity. Nevertheless, they also try to respond to this by saying that certainly the enthymeme which is conversion receives the perfection and necessity of consequence from the syllogism. But the imperfect syllogism receives only the evidence of necessity from conversion; but conversion receives the necessity of consequence from reduction into a perfect syllogism. But although many have held this way, nevertheless it seems more to us that conversion, formally speaking, is not an enthymeme, nor even any argumentation, and that conversion in doctrine or art proves nothing, but takes the converted proposition. Nor between converted propositions is there simply a diversity such as there is between what proves and what is proved; rather, conversion is a taking of the same thing transmuted according to position. And for this reason it seems that one must say that conversion is a property and disposition of the same terms, joined through being and non-being in affirmative and negative propositions, according to a diverse position. For conversion is first of terms, as was said in what preceded, namely that a proposition is converted in terms; but this will be more manifest through what follows, for a proposition is converted through the terms taken and not through propositions taken. But this seems especially to be proved from this: that if conversion were an enthymeme, that enthymeme would have to be reduced into an imperfect syllogism, and that imperfect syllogism would have to be reduced through conversion into a perfect syllogism. But if the other proposition of the imperfect syllogism is converted, and it is reduced in this way, the converted proposition will be the same as the conversion of the enthymeme, which is conversion, and as that of the syllogism which has been formed from the enthymeme. Therefore that conversion will not be something other than the premises, which is contrary to the definition of syllogism given in the preceding matters, where it was said that a syllogism is a speech in which, when certain things have been posited, something other must happen of necessity. And thus it seems that conversion is no argumentation, but first a certain passion of terms and consequently of proposition, and that it does not prove but takes the same from the same, differing nevertheless according to the position of the terms. Therefore one must say that conversion is not an argument: for every argument is reducible to syllogism; and therefore in every argument there must be terms from which two propositions are made, and one conversion diverse from the premises which are not in the conversion. And such a consequence, which is from three terms and two propositions for inferring a conversion diverse from the premises, is in every argumentation and is substantial to it, because every argumentation has to be reduced to syllogism. Since, therefore, conversion does not in this way have three terms and two propositions diverse from conversion, it cannot have such a power of consequence. But there is also another mode of consequence, which is the consequence of convertence, when something under one position of the parts follows to itself under another position of the parts; and in this way one proposition infers its converted proposition, which is the same as it, although under one position of the parts it is more known and under another position less known; and insofar as it is more known, it infers its converted proposition under another, less known position ¹.