Digital Companion to C. S. Peirce
1902 | Possibility, Impossibility, and Possible | DPP 2:315; CP 6.371
Metaphysical possibility ought to mean a possibility of existence, nearly a potentiality; but the phrase does not seem to be used in that sense, but rather in the sense of possibility by supernatural power.
‘Metaphysical Possibility’. Term in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/term/metaphysical-possibility, 16.02.2019.