ETA: Also, they regularly permit students in the Ph.D. program to concurrently achieve Master’s in different fields, allowing even more flexibility while still remaining relevant to rationality-relata. For example, students and alumni have gotten the M.S. in Mathematics, and in Machine Learning, among other areas.
Carnegie Mellon University has a program as close as any I’ve come across thus far.
Ph.D. in Logic, Computation, and Methodology
They also offer an undergraduate program, B.S. in Logic and Computation.
ETA: Also, they regularly permit students in the Ph.D. program to concurrently achieve Master’s in different fields, allowing even more flexibility while still remaining relevant to rationality-relata. For example, students and alumni have gotten the M.S. in Mathematics, and in Machine Learning, among other areas.