Monday, December 14, 2009

Meinongianism and Skepticism

Some people hold that there are a plurality of concrete possible worlds inhabited by concrete individuals who have experiences, abstract thoughts, and beliefs. One might hold this view and also believe that the actual world is ontologically special; all and only actual things exist. This is a kind of Meinongian Modal Realism.

Similarly, there are those who hold that there are a plurality of concrete times inhabited by individuals who have expereinces, abstract thoughts, and beliefs. One might hold this view and also believe that the present is ontologically special; all and only present things exist. This is Meinongian Presentism.

One problem for these views is that they seem to lead to skepticism. Consider Meinongian Modal Realism. On this view, there are lots and lots of people who have evidence much like ours that seems to indicate that they are actual. However, they are all mistaken. There is no significant difference between their evidence and our evidence. Moreover, there are so many more individuals who are mistaken than individuals who are not. So, it is highly likely that each one of us is mistaken when we believe that we are actual. So, we don't know that we are actual. A similar problem arises for Meinongian Presentism (I have also heard that Parson's briefly discusses a problem like this for Meinongianism in general).

I would like to sketch two solutions to this puzzle. I am attracted to both of these solutions and I am not sure which I like the best.

On the first solution, we must make some claims about evidence. Suppose that some experiential states are evidence (and let's, for simplicity, ignore non-experiential evidence). Should we believe that all experiential states are evidence? Perhaps not. Moreover, we might say that someone's having an experiential state is evidence for a belief only if he/she actually has that experiential state. On this view it is false that there are lots and lots of people who have evidence much like ours for the mistaken belief that they are actual. No non-actual people have any evidence whatsoever.

One strange consequence of this view is that we have to be careful how we state reductions of modal claims. Consider the claim that possibly, someone has sufficient evidence to believe that there is a dinosaur in front of him (and suppose that no one actually has sufficient evidence for that belief). On a standard modal realist view, we would say that this claim is grounded in the claim that there is an individual who is in a non-actual world and who (in that world) has sufficient evidence for believing that there is a dinosaur in front of him. But, we cannot say this if we accept the proposal above. This is because, on the proposal above, no non-actual experiential states are evidence. So, this non-actual person's experiential states are not evidence.

What we have to say, if we are going to accept the proposal above, is that the claim that possibly, someone has sufficient evidence to believe that there is a dinosaur in front of him is grounded in something else. We have to say that there are experiential states that are not evidential but that ground claims about possible evidence.

My second proposal is a bit more dogmatic (which makes me kind of like it). We might simply admit that there are lots of people who have evidential states much like ours and that those people are even justified in believing that they are actual. Unfortunately for them, they are mistaken. We, on the other hand, have evidential states that make us justified in believing that we are actual and, moreover, we are correct. So, assuming we are not in a Gettier situation with respect to the claim that we are actual, we know that we are actual.

This solution needs to be augmented a bit since the original argument for skepticism inferred from the high likelihood of mistake to a lack of knowledge. What we have to say is that even though there are lots of people out there like us and that makes it (in some sense) highly likely that we are mistaken, we still have knowledge.

Here is an analogy. Suppose we come to learn that a significant portion of the human population has been abducted and envatted by aliens. These envatted individuals have experiential states much like ours (or lets just assume that for the sake of this post), yet they are mistaken. In fact, we learn that most humans are envatted and only a small portion of the human population has true beliefs based on experiential evidence. Should this new knowledge make us suspend judgment about whether we are on earth, living non-envatted lives? I think now. We and our envatted brethren have all the same kind of evidence. We should believe that we are living non-envatted lives and so should they. It doesn't matter that we have some evidence for the claim that (in some sense) it is highly likely that we are envatted. We also have overwhelming evidence for the claim that (in some sense) it is highly unlikely that we are envatted. So do the poor envatted folks. I think we are justified in believing that we are not envatted and the envatted folks are also justified in believing that they are not envatted. We are lucky in that our justified beliefs are true and they are unlucky in that their justified beliefs are false. Hence, we have knowledge and they do not.

(Cross Posted at joshuaspencer.net)

Wednesday, December 09, 2009

Iterative Conception of Propositions

(Cross Posted at joshuaspencer.net)

The iterative conception of propositions works like this. First, we start out with some propositions at the bottom level. None of these propositions contain as a constituent the property of being true. These propositions are combined in a Boolean kind of way to get conjunctions, disjunctions, conditionals etc. Then, for each proposition at the base level and for each proposition constructed in a Boolean kind of way, there is the proposition that that proposition is true. That is, for any P such that P is a proposition at the base level or P is a proposition formed by Boolean operations on propositions at the base level, there is the proposition that P is true. This is the second level of propositions. Now, we combine these propositions and the ones at the base level and the ones formed by Boolean operations in Boolean kind of way. We get even more propositions and we do the trick over again ad infinitum. There are no propositions other than the ones formed by this series of operations.

This iterative conception of propositions will look a lot like typed propositions but will not involve a hierarchy of truth predicates. Moreover, I believe this conception of propositions will avoid certain kinds of paradoxes. There will be no liar proposition. Moreover, for any proposition P, the proposition that P is true is not a conjunct of P. Hence, there will be no Russell proposition that has itself as a conjunct iff it does not. This iterative conception of propositions is rather attractive given that it avoids these paradoxes.

We might also add to our iterative conception of propositions a kind of anti-deflationist principle. That is, for any proposition P, the proposition that P is true is not identical to P. This anti-deflationist principle will be attractive to all those who believe that there really is a property of truth.

Here is a principle that seems to follow from the iterative conception of propositions combined with the anti-deflationist principle:

Particularized Principle of Sufficient Reason (PPSR):

For any true proposition, P, there is a particular sufficient reason, S, such that (i) S is identical to the proposition that P is true, (ii) S is true, (ii) necessarily: S only if P, (iii) S is not identical to P or to any contingent conjunct of P.

However, in An Essay on Free Will, Peter van Inwagen presented a strong argument against the principle of sufficient reason (which is implied by the particularized principle above). Hence, there is a strong argument against PPSR. Very briefly, I will set out the assumptions that underlie van Inwagen’s argument and present the argument against PPSR. My formulation will follow Hudson’s formulation of van Inwagen’s argument (“Brute Facts” AJP March 1997).


Here are the five assumptions that underlie the argument:

A1. There are contingently true propositions.

A2. Any conjunction of contingently true propositions is itself contingently true.

A3. Any true proposition is either contingently true or necessarily true.

A4. For any P and Q, if both Necessarily: P and Necessarily: P only if Q, then Necessarily: Q

A5. If there are contingently true propositions, then there is a conjunction of all contingently true ptopositions.


The argument against PPSR is rather straightforward.

1) P is a conjunction of all contingently true propositions (A1, A5)

2) Hence, P is contingently true (1, A2)

3) Hence, there is a sufficient reason for P, S, such that S is true and S is identical to the proposition that P is true. (2, PPSRi, PPSRii)

4) Hence S is either contingently true or necessarily true. (3, A3)

5) S is not necessarily true (proof below)

6) Hence S is contingently true. (4, 5)

7) But, S is not contingently true. (proof below)

The proof of 5 is as follows:

a) S is necessarily true (reductio assumption)

b) Hence, necessarily: S only if P (3, PPSRii)

c) Hence, necessarily: P (b, A4)

d) It is not the case that P is necessary (2)

e) Hence S is not necessarily true (from a-d)

The proof of 7 is as follows:

f) S is contingently true (reductio assumption)

g) Hence, S is a contingent conjunct of P (e, 1)

h) S is not a contingent conjunct of P (2, 3, PPSRiii)

i) Hence, S is not contingently true (from f-g)

Since PPSR followed from the iterative conception of propositions and the anti-deflationary principle, we can conclude that A1-A5, the iterative conception of propositions and the anti-deflationary principle are jointly inconsistent. I take it that A1-A4 are all very strong. So, that leaves us with a choice. We must decide on whether we are going to give up on the iterative conception of propositions, the anti-deflationary principle, or the assumption that if there are contingent truths then there is a conjunction of all such truths. Those who are attracted to the iterative conception of propositions because it sidesteps paradox must decide between being a deflationist about truth (that is accepting that for any proposition P, the proposition that P is identical to the proposition that P is true) or denying a conjunction of all contingent truths.

Let’s consider the second option. It seems that the second option is inconsistent with the iterative conception of propositions. After all, at any level of proposition construction, we are supposed to perform Boolean operations on all those propositions constructed up to that point. We should get a conjunction of all contingent propositions at the end of our (infinitely long) construction procedure. Remember that the construction procedures should not be thought of as an actual process. Rather, we should think of the iterative conception as a thesis that involves a base clause (about the existence of certain propositions) and a recursive clause (that tells us what propositions exist given the existence of those in our base clause). The recursive clause will have a quantifier over propositions. Hence, if we are to hold on to the iterative conception without accepting a conjunction of all contingently true propositions, we must say that the quantifier in the recursive clause is indefinitely extensible. If this is all correct, then the only way a person who believes in the iterative conception of propositions can avoid a conjunction of all contingently true propositions is by endorsing a rather radical thesis about quantification (namely that the quantifiers that range over propositions are indefinitely extensible).

Hence, it looks like the defender of the iterative conception of propositions is faced with a choice. Become a deflationist about truth. Say that for every proposition P, the proposition that P is true is identical to P. Or, alternatively, claim that quantifiers that range over propositions are indefinitely extensible. Neither option seems too attractive.