A conversation yesterday (ostensibly about Heidegger) prompted me to clarify my thoughts about the logic of transcendental claims. Take, for example, the claim that the unity of consciousness requires objective experience. Let us pretend for the moment that we know what both ‘unity of consciousness’ and ‘objective experience’ mean. One natural way to gloss this claim is as follows: It is a necessary truth that any subject that enjoys unity of consciousness also enjoys objective experience. We might then formalise this
□Ax (Ux→Ox) {forgive my quantifiers, I haven't worked them out for this font yet}
Now a transcendental claim of this form has the following features: It is a necessary truth, it is universally quantified, it is synthetic and a priori (!), and just to top things off it has a conditional in the middle.
Ignoring standard qualms about quantified modal logic, the synthetic a priori, and the demand that we explain how to interpret the conditional, there are at least two distinct ways in which such claims can be challenged:
It might be suggested that we are not justified in accepting the claim as necessary.
It might be suggested that we are not justified in accepting the claim as universal.
To see this, suppose we were to become convinced that it was possible that someone could enjoy unity of consciousness without objective experience
◊ Ex(Ux & ~Ox)
How might we respond? Well, we could just dump the whole transcendental claim and give up. But that might seem overly drastic.
Another move is to drop the necessity operator, either entirely or replace it with ‘It is physically necessary that...’. The first option turns the transcendental claim into a contingently true generalisation. The second into a physical/nomic necessity. The second option is (i) only available if we think that the putative counterexample involves an infraction of the laws of nature, and (ii) we can plausibly maintain that this truth really does follow from the laws – for we have an idea of what an epistemology of nomic necessities looks like (science). So on either option, it seems that the a priority of the transcendental claim would have to go. [Then again, might transcendental claims be understood as contingent a priori truths? One would have to look for similarities with the best Kripke-style examples of such things. I need to think about this].
However, an alternative move is to restrict the quantifiers in such a way as to disqualify the putative counterexample. So, we might say that the domain is restricted to beings like us in respect R. In this case, we would still have a necessary truth and knowledge of it might still be a priori. The difficulty with this move would be that we would need to specify what respect R is in such a way to prevent the transcendental claim looking like a trivial consequence of an ad hoc move. Still, that might be preferable to the earlier option of turning transcendental claims into contingent generalisations or physical necessities.
What if we were to discover an actual counterexample [Ex (Ux & ~Ox)]? Well, the first option (dumping/changing the necessity operator) is not an option, but the second remains a possibility. I’m thinking of Beatrice’s interpretation of Foucault as putting forward transcendental claims limited to contemporary westerners. Of course this would have nothing like the strength of the original claims, but might still be of some interest.
