“Truth and falsity imply combination (copulation) and separation.”
The denial must deny just that which the affirmation affirms concerning the same subject, and must correspond with the affirmation both in the universal or particular character of the subject and in the distributed or undistributed sense in which the proposition is understood. If anything else be negatively predicated of the subject or if anything else be the subject though the predicate remain the same, the denial will not be the denial proper to that affirmation. The denial proper to the affirmation ‘every man is white’ is ‘not every man is white’; that proper to the affirmation ‘some men are white’ is ‘no man is white’, while that proper to the affirmation ‘man is white’ is ‘man is not white’.
Necessity and Potentiality
“Now that which is must needs be when it is, and that which is not must needs not be when it is not. Yet it cannot be said without qualification that all existence and non-existence is the outcome of necessity. For there is a difference between saying that that which is, when it is, must needs be, and simply saying that all that is must needs be, and similarly in the case of that which is not. In the case, also, of two contradictory propositions this holds good. Everything must either be or not be, whether in the present or in the future, but it is not always possible to distinguish and state determinately which of these alternatives must necessarily come about. … For in the case of that which exists potentially, but not actually, the rule which applies to that which exists actually does not hold good.”
In retrospect, there is only necessity; in prospect, there is potentiality. In death, there is only impossibility; in life, there is freedom.
Between Necessity and Potentiality
“Necessity and its absence are the initial principles of existence and non-existence, and that all else must be regarded as posterior to these.
That which is of necessity is actual. Thus, if that which is eternal is prior, actuality also is prior to potentiality. Some things are actualities without potentiality, namely, the primary substances; a second class consists of those things which are actual but also potential, whose actuality is in nature prior to their potentiality, though posterior in time; a third class comprises those things which are never actualized, but are pure potentialities.”