This question occurred to me in the course of addressing a recent question about what counts as evidence in philosophy. There, I offered that transcendental arguments are structurally akin to indispensability ones, as if the argument schematics are inverses or reciprocals of each other. This, I claimed, turns on the reciprocity of apriority vs. aposteriority. But is my claim accurate? I also claimed that indispensability arguments rely on the theory of ontological commitment, but the phrase "ontological commitment" shows up nowhere in the SEP article on transcendental arguments, and it does show up seven times in the SEP article on the indispensability argument in the philosophy of mathematics. And yet here is what the IEP article on transcendental arguments says:
A modest transcendental argument establishing the indispensability of a conceptual framework has the effect of reducing the skeptic either to inconsistency or to raising doubts in the abstract. Since the alternative is inconceivable, the skeptic cannot consistently commit to the possibility of the alternative. [emphasis added]
Apparently Enoch[11] at one points reads:
My indispensability argument for Robust Realism may be thought of as a kind of a transcendental argument.
I can't get the full text of Stokes[07] but the Google outside snippet keyed to the relevant phrases has it that the article at one point reads:
Vahid[11] seems to have a certain class of transcendental arguments as indispensability arguments:
Accordingly, while objective transcendental arguments seek to reveal truths about the world, the subjective variety is intended to show why certain beliefs are indispensable for having thoughts, experiences and so on. I call these first-order and second-order transcendental arguments respectively (reflecting the type of content their conclusions express). With this distinction in mind, I shall now proceed to show that, their surface structure notwithstanding, transcendental arguments are actually species of inference to the best explanation. [bold-face emphasis added]
Are transcendental arguments the apriority-theoretic reciprocals, structurally-speaking, of more empirically-minded indispensability arguments? Or are we really just using multiple names for the same epistemic phenomenon?
