Deception will frequently occur from the terms of the proposition being improperly expounded, as if A should be health, B disease, and C man, for it is true to say that A cannot be with any B, for health is with no disease, and again that B is with every C, for every man is susceptible of disease, whence it would appear to result that health can be with no man. Now the reason of this is, that the terms are not rightly set out in expression, since those words which are significant of habits being changed, there will not be a syllogism, as if the word "well" were taken instead of "health," and the word "ill" instead of "disease," since it is not true to say, that to be well cannot be present with him that is ill. Now this not being assumed, there is no syllogism except of the contingent, which indeed is not impossible, for health may happen to be with no man. Again, in the middle figure there will likewise be a falsity, for health happens to be with no disease, but may happen to be with every man, so that disease shall be with no man. In the third figure however falsity occurs by the contingent, for it is possible that health and disease, science and ignorance, in short, contraries, shall be with the same individual, but it is impossible that they should be present with each other: this, however, differs from the preceding observations, since when many things happen to be present with the same individual they also happen to be so with each other.
Evidently then in all these cases deception arises from the setting forth of the terms, as if those are changed which relate to the habits, there is no falsity, and it is therefore apparent