Return to Aristotle, On Interpretation
1. The consecutions, however, when properly made are disposed as follows: The (enunciation), it may happen to be, follows this, it is possible to be, and this reciprocates with that; and also this, it is not impossible to be, and this, it is not necessary to be. But this, it is not necessary not to be, and it is not impossible not to be, follow that, it is possible not to be, and it may happen not to be; and thus, it is necessary not to be, and it is possible to be, follow that, it is not possible to be, and does not happen to be. But this, it is necessary to be, and also this, it is impossible not to be, follow this, it is not possible not to be, and it is not contingent not to be. What we say, however, may be surveyed from the following description. It is possible to be. It may happen to be. It is not impossible to be. It is not necessary to be. It is not possible to be. It may not happen to be. It is impossible to be. It is necessary not to be. It is possible not to be. It may happen not to be. It is not impossible not to be. It is not necessary not to be. It is not possible not to be. It may happen not to be. It is impossible not to be. It is necessary to be.
2. The impossible, therefore, and the not impossible, follow contradictorily the contingent and the possible, and the not contingent and the not possible, but vice versa. For the negation of the impossible, viz. it is not impossible to be, follows the enunciation it is possible to be; but affirmation follows negation. For the enunciation, it is impossible to be, follows this, it is not possible to be; since, it is impossible to be, is affirmation, but, it is not impossible to be, is negation.
3. Let us also see how the necessary subsists. It is evident, therefore, that it does not subsist in this manner, but contraries follow; and contradictions [are placed] separately. For, the enunciation, it is not necessary to be, is not the negation of it is necessary not to be; since it may happen that both may be verified in the same thing. For that which necessarily is not, has not a necessary existence.
4. But the reason why the necessary does not similarly follow the other enunciations is this, that the impossible being enunciated in a way contrary to the necessary signifies the same thing. For with respect to that which it is impossible should exist, it is necessary not that it should be, but that it should not be; and with respect to that which it is impossible should not be, it is necessary that it should be. Hence, if those similarly follow the possible and the not possible, these follow in a contrary mode; because the necessary and the impossible do not signify the same thing, but, as we have said, vice versa.
5. Or is it impossible that the contradictions of the necessary should be thus arranged? For that is possible to be which necessarily is. For if not, negation would follow; since it is necessary either to affirm or deny; so that if it is not possible to be, it is impossible to be. Hence it is impossible for that to be which necessarily is, which is absurd. But the enunciation, it is not impossible to be, follows this, it is possible to be, and this again is followed by, it is not necessary to be. Hence it happens that what necessarily exists, does not necessarily exist, which is absurd.
6. Moreover, neither does the enunciation, it is necessary to be, nor the enunciation, it is necessary not to be, follow this, it is possible to be; for to that both may happen; but whichever of these is true, those will be no longer true. For at one and the same time [these are true] it is possible to be, and it is possible not to be. But if it is necessary to be or not to be, both will not be possible. It remains, therefore, that this enunciation, it is not necessary not to be, should follow, it is possible to be.
7. For this also is truly asserted of that which has a necessary existence.
8. For this becomes the contradiction of the enunciation which follows it, viz. it is not possible to be; since it is impossible to be, and it is necessary not to be, follow that; of which the negation is this, it is not necessary not to be. These contradictions, therefore, follow according to the above-mentioned mode; and no absurdity happens when they are thus arranged. Possible to be. Contingent to be. Not possible to be. Not necessary not to be. Possible not to be. Contingent not to be. Not impossible not to be. Not necessary to be. Not possible to be. Not contingent to be. Impossible to be. Necessary not to be. Not possible not to be. Not contingent not to be. Impossible not to be. Necessary to be.
9. Some one, however, may doubt whether the enunciation, it is possible to be, follows this, it is necessary to be. For if it does not follow, the contradiction, it is not possible to be, will follow. And if any one should say that this is not a contradiction, it is necessary to call this a contradiction, viz. it is possible not to be; both which are false of that which necessarily exists. Again, however, it may appear to be possible, that the same thing may be cut and may not be cut, may be and may not be; so that which necessarily is, may happen not to be. This however, is false.
10. But it is evident that not every thing which can be, or can walk, has also the power of effecting the opposites; but there are some things in which this is not true. In the first place, in those things which have power without reason; as, for instance, fire is calorific, and has an irrational power. The powers, therefore, which subsist in conjunction with reason, are the powers of many things and of such as are contrary. Not all irrational powers, however, are capable of this; but as we have said, fire has not the power of heating, and not heating; nor such other things as always energize. Yet some things among those which possess irrational powers can at one and the same time receive opposites. This, however, has been said by us, because not every power is susceptive of contraries, not even such as are predicated according to the same species.
11. But some powers are homonymous; for the possible is not simply predicated; but one thing is said to be possible, because it is true, as being in energy. Thus, it is possible for a man to walk, because he walks; and, in short, a thing is possible to be, because that is now in energy which is said to be possible. But another thing is said to be possible, because it can be in energy. Thus, it is possible for a man to walk because he has the power of walking. And this power alone exists in moveable natures; but that in such as are immoveable. But with respect to both it is true to say, that it is possible to walk, or to be, and that a man now walks and energizes, and that he has the power of walking. Hence, that which is thus possible, is not truly asserted of that which is simply necessary; but the other is truly asserted.
12. Hence too, the universal follows that which is in a part; and to be able to be, though not all ability of this kind, follows that which exists from necessity.
13. And perhaps, indeed, the necessary and the not necessary are the principle of the existence, or non-existence of all things; and it is necessary to consider of other things as consequent to these. Necessary to be. Not possible not to be. Not contingent not to be. Impossible not to be. Necessary not to be. Not possible to be. Not contingent to be. Impossible to be. Not necessary to be. Possible not to be. Contingent not to be. Not impossible not to be. Not necessary not to be. Possible to be. Contingent to be. Not impossible to be.
14. From what has been said, therefore, it is evident, that a thing which is from necessity, is in energy. Hence, if eternal natures have a prior subsistence, energy also is prior to power (i. e. to capacity). And some things, indeed, are energies without capacity, as, for instance, the first essences; but others are energies together with capacity; and these are, indeed, prior by nature, but posterior in time; and others are never energies, but are capacities only.
Return to Aristotle, On Interpretation
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