A-T axioms on possibility

1.) Possibility is always relative to the actual. Where “actual” means “what is” simply speaking. Possibility is possibility to be, where “to be” must be understood as different from the possible (if not, then “possibility to be” is possibility to the possible, and this second possible will be possibility to be, which makes possibility nothing other than possibility to be possible to be possible… ad infinitum).

Thus, from the very first account of possibility, it is impossible to conceive it as an absolute: as some sort of etherial cloud that can become “instantiated”, or as some “world” that can serve as a unity that can be multiplied out to make many or all “possible “worlds”. Possibility cannot be or be thought apart from relation to another.

But doesn’t this do away with possibility not to be? No. It simply requires that the possibility not to be is itself understood to the very being with is negated. The relation to being distinct from possibility is required in either case.

2.) Possibility divides into the real and the logical. The “what is” that is distinct from the possible can be either subsistent or not. In other words, the “being” that is distinct from the possible, and to which the possible both is and is understood, is not of necessity subsistent.

3.) There is a possibility as opposed to the necessary (N) and as opposed to the impossible (I). In other words, (N) negates necessity; (I) negates impossibility. All that is (N) is (I), but the reverse does not obtain. God, for example, is possible (I) and not (N). The same is true of energy and matter, since it can neither be generated or destroyed (assuming they are not simply possibilities themselves). At any rate, this is true of the most causal things in nature: they are possible (I) but not (N).

4.) By abstracting from the difference between real and logical possibility, one gets another mode of logical possibility. The possibility that arises from this sort of abstraction is by definition indifferent to the real, and so is logical, though not for precisely the same reason as it was distinguished in axiom #2. To be opposed (#2) is not the same thing as to be indifferent (#4).

5.) Logical possibility (#4) is also called absolute possibility. It is absolute because it can be said of all modes of possibility. It is the most general account of possibility that can be given. It is possibility with no qualifications whatsoever.

6.) Absolute possibility is only possible not to be. The whole possibility of absolute possibility consists in this: it is not necessary that it not be. Oblivion is not required of it. This is all. Remember, we have abstracted from the difference between the real and the logical here (or the “ontological” and “epistemic” as Contemporary persons call them.)

This relation is possible because being is principally opposed to non-being, and secondarily to possibility. This allows for a possibility that is opposed simply to non-being.

(I’m working on this last one, and might change the explanation, though I think the axiom itself is good.)


  1. phamilton said,

    May 17, 2010 at 2:28 pm


    Do you know of any specific places where Thomas can been said to to understand absolute possibility in the way you describe it? I’ve seen the phrase used several times in Thomas’ writings, and there seems to be a bit of disagreement over what it means.

    • May 17, 2010 at 5:54 pm

      It’s probably not a matter of black-letter St. Thomas- but I think the interpretation I give here is a simplest way to harmonize the division of potency or possibility given in In Met. IX with the division given in QDP 1. a. 3 co. In the former, real possibility is divided from metaphorical (or logical) possibility; in the latter, real possibility is divided into what reduces to a cause, and what is said “secundum se”, and both are divided against logical possibility. I call “secundum se” absolute, It is not properly real, since it does not reduce to some active or passive cause, but it is also opposed to mere logical possibility. The simplest account is that it simply abstracts or prescinds from the difference between the real and the logical.

      I suppose there is some dispute about this, but I’m a Postmodern man so I can just claim to be tired of all those petty squabbles that divide us. By temperament I have only a lukewarm interest in inner-Thomist disputes.

    • phamilton said,

      May 18, 2010 at 9:29 am

      Thanks. I’ll have to think about it a bit more.

      My problem with intra-Thomist disputes is that there is frequently more focus on exegesis than doing actual philosophy. I actually had this suspicion for the first time when dealing with how we reconcile Aristotle’s account of possibility with Thomas’; one author raised some interesting objections to show that the two are inconsistent, and the others responded by doing textual analysis to confirm that their own interpretation indeed got Thomas’ opinion right; but they stopped there and never actually answered the objections. That exchange left a sour taste in my mouth: it seemed to implicitly assume that if the authority Thomas said it, then it must be correct. I cannot think of an approach to Thomas that captures the spirit of his project less.

      I find such objections valuable insofar as they help clarify what is true; otherwise, I’m rather lukewarm to such disputes myself.

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