A recent conversation with a friend (Michael) inspired me to offer the following comments and thought experiements. The broadly idealist perspective maintains that, at bottom, the only thing which exists is actually experience. This runs against my intuition, as I would agree with Bonaventure and others that at bottom the one thing which exists is being itself. However, let me put my ideas to one side and try to picture a world in which an idealist-modality holds.
On my view, propositions exist independent of any human being cognizing them, and they have a truth-value assignment without anybody cognizing them or cognizing their truth-value. This is because all propositions are found in the mind of God. Thus to say that there is some logically possible world, is simply to say, at bottom, that God has some idea of the world which is identical to the picture I am proposing. To say that that picture of the world is non-actual is to say that it does not obtain in the world which God has (ultimately and providentially) realized. This view can be found in Plantinga and others, and I am also deeply influenced by the work of Alexander Pruss.
On the Idealist view, it seems that at bottom only experience exists. Propositions, then, do not exist mind-independently (as numbers do on my view as well). Propositions, in one sense, begin to exist once they are cognized, or else when it is possible to cognize them. Therefore some agent S who cognizes a proposition P for the first time, where nobody has ever cognized P before, may have cognized a proposition without a truth value assignment! That is to say, if they have cognized it without cognizing it’s truth-value assignment, then since cognition here is the ‘ground-of-being’ for propositions, then it’s truth-value as of yet does not exist. So that the proposition at the time of cognition (T1) is not either true or false (ie, neither true nor false). Now, Michael has responded to me saying that on his view the proposition may in fact have a truth-value assignment based on a standard against which the cognizer might compare it, and thanks to which the cognizer could understand the proposition at all. Indeed, without this ‘standard’ or ‘paradigm’ no propositions could exist (let alone be articulated). So, perhaps S cognizes P and does not cognize it’s truth-value, but yet has some standard/paradigm whereby S can in principle find P’s truth-value assignment. For instance S may have cognized 612×5=3060 before having calculated and found out that, actually the proposition “612×5=3060” was true. However, the ‘means’ to get to the answer were in principle available to S when S conceived of the proposition. They were available according to the ‘paradigm’, and it is only in that paradigm that they could be understood or articulated as propositions. (Propositions which cannot be articulated may not exist).
However, there are some ‘paradigms’ which allow us to understand certain propositions without those propositions being analytic truths. For instance, if a number of speculative scientists have multiple running theories or ‘models’ of relativity or quantum theory, maybe the empirical evidence at hand simply doesn’t allow one to privilege one over the others. A staunch Empiricist may respond to this by arguing that when two theories are not only currently equally supported by empirical evidence, but moreover neither offers any way to verify one’s truth given some possible empirical data, then the two theories are empirically equivalent and the difference is ‘semantical’ and not ‘real’ (here meaning empirical).
So then, let us imagine a logically possible world with exactly one cognizer. (Note that for the idealist, it is not logically possible for there to be a world in which no cognizer exists, since the only thing that exists is experience itself, and thus without any ‘agent-of-experience’ in some model of the world, there simply IS no world, and certainly no propositions – ie without the cognizer there just IS no model of the world). Let us imagine this one cognizer to have a set of experiences and memories, and a ‘paradigm’ in which to understand and express propositions. Let us further imagine that she conceives of some proposition P1, such that P1 is understandable in terms of the paradigm. At the time when she first conceives P1, she has not as yet conceived a truth-value assignment for it. Let us imagine further that her paradigm allows her in principle to find out whether P1 is true or false. However, for her to find out whether it is true or false, she needs some additional empirical data, some set of experiences that she has not as of yet aquired. Since experience is, at bottom, ‘all there is’ then doesn’t this mean that the proposition may, at some time, exist without a truth value assignment? Even if she comes to have those experiences which lead her to conclude that P is true (verified by experience), what makes it the case that P is true? So, what makes the proposition to be true or false is not it’s actually being ‘true’ or ‘false’ mind-independently, but rather some set of experiences that a cognizer has.
This interestingly leads us to conceive of another relevantly-similar logically possible world with one cognizer, the same proposition, and the same lack of experiences needed to determine P’s truth value assignment. In this second possible world, let us imagine that the cognizer eventually has precisely the set of experiences which will make it the case that he knows that P is false.
For fun, if somebody wants to object by saying that P may merely ‘seem’ true or false given some experiences, but is actually (even for the idealist) true or false objectively apart from those experiences (for instance by having a ‘repeatability’ standard with a wider pool of verified instances of the types of experiences necessary to determine P’s truth). Make P to be something like this: “tomorrow I will be presented to bluely (that is, I will have the experience of something blue)”. Well, we have an understanding of what it means, and we can say that the proposition is not either true or false until experience makes it so. Additionally experience really does make it true or false in one instance of experience (or lack thereof).
So, it seems to me that the idealist has to say that some propositions at some time simply do not have truth-value assignments. That experience literally ‘makes it true’ of the world. This may hold interesting implications for a B theorist who is an idealist – perhaps they will argue that such propositions could be true apart from anyone being able in principle to determine their truth. Perhaps the idealist will say instead that it is possible in principle to determine their truth by appealing to a ‘pattern of experience’ along with the assumption of ‘determinism’ (here, meaning something analogous to physical determinism, perhaps experiential-determinism or something).
Conclusion: it seems that the idealist is bound to end up on the same page as Mathematical intuitionists who deny that the Law of Excluded Middle is, as such, true, but rather maintain that Truth is just demonstrability. What the consequences are for modality at large, I’m not sure yet.
I know Michael will want to comment, so I invite comments and thoughts from him especially, and from anyone else.