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02/15/2013

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Marcus Arvan

Ted: quick question about Rasmussen's argument. How is his argument for 1.1 not just another form of the Cosmological Argument?

Along the same vein, I'm not sure I agree with you (or Rasmussen) that (4) -- the basis of his case for 1.1. -- is extremely weak. 1.1's claim -- that it is *possible* for there to be a world where all contingent things are caused -- seems to me *identical* to (4): the claim that a necessary being is possible. After all, any causal series of contingent beings is *itself* a contingent being -- in which case, for *it* to have a cause, there would have to be a necessary being. In which case Rasmussen's argument is question-begging (and just an assertion of the Cosmological Argument, which sort of defeats the purpose of a defense of the Ontological Argument!). Or maybe the mistake here is mine...Have I missed something?

T. Parent

Yes, it is indeed has features of the Cosmo arg., though it purports to show something stronger from something weaker. Instead of postulating a cause of the actual world, it starts with a cause of all contingencies in some possible world or other. And then it purports to show that this cause *necessarily* exists.

I think you're right that one could just deny (4) in response to Rasmussen. And I might have been a bit too accommodating when I stressed how weak it seems. But I wouldn't say that (4) is equivalent to (1.1). After all, you also need (5) to get to (1.1), and (5) might be challenged by believers in backwards- or simultaneous-causation. (Again, to be accommodating, I briefly defended Rasmussen against those folks. But I think there remains an issue. After all, if backwards causation allows for circular causation, then there may be no sense in which the cause is prior to the effect. For the cause of the effect would also be the effect of the effect.)

Marcus Arvan

Hi again, Ted. Thanks for the clarification! A new question: I wonder whether the modal fictionalist can't (as you say) get (8) for free. Isn't it a *part* of modal fictionalism that the fiction is literally true at the actual world? That is, isn't the structure of modal fictionalism (roughly) the following:

(1) The actual world exists.
(2) Possible worlds don't really exist
But,
(3) Modal truths are truths-in-fiction about worlds (all of which are non-actual except for one -- the actual world).
So,
(4) Although modal truths about non-actual worlds cannot be used to derive existence claims (i.e. about God).
(5) Modal truths about the actual world *can*, since in the actual world the relevant fiction (by definition) *refers* to actuality.

You suggest on p.7 that if the modal fictionalist holds that her preferred fiction "has (8) in mind", then the argument is question-begging. However, this seems to me to get things the wrong way around. (8) is not a first-order modal claim within fictionalism; it's an axiom a partly *constitutive* of fictionalism itself (in the meta-language; viz. isn't that why "F" is bolded in the formula? note: I may be mixing things up here. It's been a long time since I've done any modal logic).

Anyway, I suspect I've probably made a silly mistake here, but anyway that's my main worry at the moment. Perhaps, if I'm right -- if the fictionalist gets (8) for free -- the thing to say is that there's something just bizarre about deriving the existence of actual objects from fictions about non-existent worlds............

Aha. Something *just* occurred to me as I was writing that. Perhaps the real problem -- the real lesson to be learned from your paper -- is that a fictionalist should reject *S5*. I mean, I know Plantiga defends it, but for a fictionalist S5 seems bizarre for precisely the reasons you're alluding to in the paper: S5 enables fictions to demonstrate the existence of *actual* objects (which intuitively no fiction should be able to do).

Just a shot in the dark. Maybe I'm off the reservation. ;)

T. Parent

Hi Marcus,
Thanks very much for your comments. I think you're right that (8) is part of the standard fictionalist picture. And right, if that's so, then it seems ontological arguer can say to me "look, *you* brought fictionalism into the fray--yet since (8) is part of fictionalism, the modal argument still works fine!"

But think of it this way. In the context of the dialectic, I am provisionally assuming that all of fictionalism except (8) is true. (That's allowed since one can provisionally assume whatever one wishes.) Under this set of suppositions, I then draw out that it's possible for the premises of the modal argument to be true while the conclusion is false. The next step is to say that my provisional set of assumptions has not been ruled out. And that establishes that, so far as has been shown, there's the possibility of true premises and false conclusion.

You're right that it's perhaps not fictionalism *per se* that establishes the fallacy, and that's a useful thing for me to clarify. But in the end, I don't believe the point affects the argument... Or am I misunderstanding?

Moti Mizrahi

Ted: I thoroughly enjoyed reading your paper.

I can see one point that needs further clarification. It wasn’t clear to me whether you want to argue that the modal argument is invalid or unsound. You say that it commits “the existential fallacy,” which suggests that it is invalid. That is, as I understand it, you want to argue that, given modal fictionalism is a live option, claims about necessary beings cannot be derived from claims about possible worlds. In other words, unless we can rule out the inference from ‘possibly p’ to ‘fictionally p’, the inference from the former to ‘necessarily p’ may be invalid.

On the other hand, if you want to argue that the modal argument is unsound, then here is how I understand the gist of your argument:

1. The modal argument presupposes modal realism.
2. Modal realism is not the only game in town (there is also modal fictionalism).
3. Therefore, the modal argument is unsound.

Perhaps I have misunderstood your argument. In any case, my suggestion is simply to clarify whether you are charging the modal argument with invalidity or unsoundness. I hope this is helpful.

Marcus Arvan

Hi Ted: Thanks for the response. However, I'm still not quite clear on the dialectic.

It seems like you want to say that if we assume everything about fictionalism except for (8), then the modal ontological argument commits the existential fallacy. My worry, though, was that the fictionalist should say: "Well, of course! If you assume away the part of our theory that would make the ontological sound, *then* the argument is fallacious. But that's just to jury-rig our theory to get the result you want. Our theory of modality presupposes (8), and if (8) is true then the ontological argument commits no fallacy."

I'm still very sympathetic with the overall thrust of your argument, but I also still think you might be better off arguing (on the grounds you do!) that the fictionalist has good reasons to reject *S5*. After all, what's so strange about S5 in fictionalism? Answer: S5 permits deriving existence claims in the actual world from possibility claims in *fictions*. But that's exactly what you're taking issue with, right? So, instead of going at from the direction you presently are -- dropping (8) -- why not just go along with the fictionalist in assuming (8) and take issue with S5 instead?

As an aside, this (different) tack would have an added benefit. Whereas your argument purports to raise an "issue" for fictionalism (which you note on pp. 10-11), if the alternative diagnosis I'm offering is right, your argument is *good* news for the fictionalist: namely, because if fictionalism requires dropping S5, then the fictionalist has a good *explanation* of what's so intuitively wrong with the ontological argument!

Or am I way off the reservation...?

T. Parent

Thanks Moti very much for taking the time to read/comment.

In the first instance, I mean to say that the modal argument is invalid. (Caveat: The ontological arguer could respond that there's an implicit premise "if all my premises are true, then so is the conclusion." In that case, the argument is valid but rests on a contentious premise.)

By the way, I don't want to say that the ontological argument requires modal realism to be valid. I realize the draft insinuated that, but it's not quite right. Rather, the argument requires modal facts to be genuine facts rather than just facts-according-to-the-fiction. Genuine modal facts do not have to be facts about concrete possible worlds; indeed, Adams and Plantinga hold instead that they are genuine facts about actual sets. But at least, the ontological arguer needs to say that modal facts are not just facts-in-fiction.

T. Parent

Hi Marcus--thanks for pressing me on this issue; I think you're right that I need to be clearer here.

I mean to concede your point that, strictly speaking, it is not *modal fictionalism* that brings out the fallacy in the modal argument. It's true that if we accept modal fictionalism (incl. (8)), then the modal argument is valid.

Nevertheless, in my earlier comment the claim was that modal fictionalism minus (8) still brings out the crucial point: That it's possible for the premises of the modal argument to be true while the conclusion is false. As long as one grants the possibility of modal fictionalism minus (8), the point stands.

On further reflection, however, I realized there may be a more convincing angle on this. Start by observing that modal fictionalism (w/ (8)) is contentious, given that there are other options for your modal metaphysics. One can thus imagine, say, a modal realist, objecting to fictionalism along the following lines. "Look, by your own lights, 'facts' about possible worlds are just things we *made up*. But things we make up can't be assumed reliable, re: the actual world (at least, not without further argument). Yet fictionalism just baldly assumes that what the fiction entails about the actual world is true. But that's crazy--you can't trust a *fiction* on how the actual world is (unless you have further argument)."

This is more or less what I'm saying to the ontological arguer, once we admit that modal "truths" might just be something we made up. Granted, a fiction may per accidens contain actual truths. But we cannot *assume* as much (w/o further argument). And without that assumption, if modal truth is truth-in-fiction, the conclusion of the modal argument does not follow.

Btw, I now realize that this last maneuver assumes S4, and that may be a problem. Still, S4 is weaker than S5, which is apparently what you'd like to reject. I may want to reject S5 too, but unfortunately, I don't think my argument warrants that... For the argument may reflect instead that (1) or (1.1) is false ("possibly, a necessary being exists").

Marcus Arvan

Ted: Thanks for clarifying, but I really think your argument -- as you just laid it out -- is tantamount to a denial of S5. For let's think about your basic idea: fictional worlds we just "made up" intuitively shouldn't suffice to establish existence claims in the actual world. This seems entirely right and plausible to me. But notice what it is identical to claiming: namely, that our world shouldn't be modally accessible from possible worlds that are accessible *from* our world -- which is simply a denial of *symmetry* (the assumption that distinguishes S5 from S4!

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