universal and the propositions are of a universal character, or when

it is individual, as has been said,' one of the two must be true and

the other false; whereas when the subject is universal, but the

propositions are not of a universal character, there is no such

necessity. We have discussed this type also in a previous chapter.

When the subject, however, is individual, and that which is

predicated of it relates to the future, the case is altered. For if

all propositions whether positive or negative are either true or

false, then any given predicate must either belong to the subject or

not, so that if one man affirms that an event of a given character

will take place and another denies it, it is plain that the

statement of the one will correspond with reality and that of the

other will not. For the predicate cannot both belong and not belong to

the subject at one and the same time with regard to the future.

Thus, if it is true to say that a thing is white, it must

necessarily be white; if the reverse proposition is true, it will of

necessity not be white. Again, if it is white, the proposition stating

that it is white was true; if it is not white, the proposition to

the opposite effect was true. And if it is not white, the man who

states that it is making a false statement; and if the man who

states that it is white is making a false statement, it follows that

it is not white. It may therefore be argued that it is necessary

that affirmations or denials must be either true or false.

Now if this be so, nothing is or takes place fortuitously, either in

the present or in the future, and there are no real alternatives;

everything takes place of necessity and is fixed. For either he that

affirms that it will take place or he that denies this is in

correspondence with fact, whereas if things did not take place of

necessity, an event might just as easily not happen as happen; for the

meaning of the word 'fortuitous' with regard to present or future

events is that reality is so constituted that it may issue in either

of two opposite directions. Again, if a thing is white now, it was