Page:O. F. Owen's Organon of Aristotle Vol. 1 (1853).djvu/142

 necessarily present with certain things, on this account, we say that it is not contingent to every individual. Wherefore the being present necessarily with a certain thing, and the not being present with a certain thing necessarily, are opposed to the being contingently present with every individual, and in like manner, there is a similar opposition to the being contingent to no individual. Hence it is evident, that when the contingent and non-contingent are taken, in the manner we first defined, not only the necessarily being present with a certain thing, but also the necessarily not being present with it, ought to be assumed; but when this is assumed, there is no impossibility to a syllogism being produced, whence it is evident, from what we have stated, that a negative contingent is not convertible.

This then being demonstrated, let A be assumed contingent to no B, but contingent to every C; by conversion, therefore, there will not be a syllogism, for it has been said that a proposition of this kind is inconvertible, neither, however, will there be by a deduction per impossibile. For B being assumed contingently present with every C, nothing false will happen, for A may contingently be present with every and with no C. In short, if there is a syllogism, it is clear that it will be of the contingent, (because neither proposition is assumed as de inesse,) and this either affirmative, or negative; it is possible, however, in neither way, since, if the affirmative be assumed, it can be shown by the terms, that it is not contingently present; but if the negative, that the conclusion is not contingent, but necessary. For let A be "white," B "man," and C "horse," A therefore, i.e. "whiteness," is contingently present with every individual of the one, though with no individual of the other,