Some dialectical arguments about the idea of a possible world or worlds

Possible world talk is a dialectical tool- a sort of way of proceeding “as if”. It is like making a universal a circle, as Venn diagrams do. This is fine, but there are some shortcomings of the tool, since there are unavoidable shortcomings in describing possibility as a world, irrespective of what one says about it after that.

First, possibility can’t exist without a relation to another, which means it lacks the conceptual or real autonomy that a  world has to have. Speaking of a possible world is like speaking of a “left side” world or an “above” world. What would a left side world be? If it means anything, it would have to be some concept or real mode of existence that was just left sides. But “left” isn’t the sort of thing that can exist in this way: it is always characterized by the double relation to both right and some animal which exists in space and as a self. Possibility to be actual and actuality are separable and distinct, but not in such a way that possibility gains the sort of autonomy or independence of concept that would allow someone to call it a “world”.

But what about absolute possibility? Doesn’t this have a quasi-separable character, at least in thought? Yes, but it also isn’t able to be actualized, even in thought. Absolute possibility is possibility as considered in the proposition “the possible can be or not be”. But that mode of conceiving the possible makes it a state, like “running”- but it is not running that runs or running that goes from resting to moving or here to there.

More to the point, absolute possibility explicitly prescinds from the difference between real and logical possibility. If one makes a “world” out of absolute possibility, then it is impossible to answer, even in principle, whether this world is real or sheerly logical; and thus whether it can be actualized, instantiated, etc.. In fact, such questions are no different than asking “is figure a square or a circle?”

One crucial problem for any coherent idea of a possible world is the axiom in perpetua non differt esse et posse. Given an endless amount of time, all that is possible will be actual. This is a thorny axiom, which needs a good deal of dialectical lead-up- one has to speak, among other things, about the possibility for simultaneous contradictories- since its not both sides of a contradiction that are actualized, though both are possibile. This is not the sense of the axiom, but rather it articulate the absolute dependence of real possibilities on the activity of a cause, so much so that where the activity of this cause is forever ruled out, possibility is ruled out also. It is, among other things, a statement of the dependence of possibility in its existence to that which is not merely possible.

Possible world talk will unavoidably confuse temporal and ontological priority. Possibility is prior in time, not in existence; and no account of possibility can give it primacy of existence, even when we reduce possibilities to the divine ideas. Such a reduction does reduce creation to the creator, but within the creator himself these possibilities must be seen as arising in the mode of an artificer, and thus as derivative and secondary. Failing this, we will make the world arise from God in the way that the Second Person of the Trinity arises. The world will thus become equal to God- arising from the very necessity of his immanent operation. Even possible worlds as divine ideas have the ratio of being secondary so far as they must be seen as arising in the mode of art as opposed to nature.



  1. Damien S said,

    June 7, 2010 at 10:36 pm


    Really interested in your blog. Is there any academic references where these arguments against Possible Worlds have been put forth? Especially the “as if” status of PWs.

    Damien (PHD candidate at Macquarie University)

  2. June 8, 2010 at 8:31 am

    Nope. This post is all I know about, other than the one Feser just wrote.

    This is not to say that there have not been critiques of PW’s (I’ve been told that James Ross argues for the inseparability of possibility from some actuality- which makes it difficult to say that possibility is the sort of thing that could be a world- but I don’t have a reference.) But I haven’t yet read an Analytic philosopher who appreciates the sort of distinctions I am making here in the critique. AP’s have no philosophy of nature and do not show the least interest in finding one. To be blunt, I have no confidence that any real dialogue is possible.

    Don’t get me wrong, I’m not saying I’m a genius and the AP’s are dolts- many of them are scary brilliant- but there is simply an unbreachable gulf between what an AP thinks philosophy is and what a Thomist thinks it is.

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