Against the pervading opinion, the author took the positive side of the question, “Does logic rest on a metaphysical foundation?” Logic is generally understood as a science that investigates ways of distinguishing good from bad arguments. This conception leads many to think that logic does not rest on any metaphysical foundation—that it is not an ontologically-committing enterprise. To claim that “‘Someone is male’ logically follows from ‘Joey is male’” does not commit one to the existence of maleness or the existence of Joey, even if it is logically true that if Joey is male, then someone is male. This paper, however, argues for the contrary thesis. In one possible rendering of what logic means and in one possible understanding of what it is for someone to be ontologically committed to something else, it can be shown that logic is an ontologically-committing activity. From this, it is argued that logic has a metaphysical foundation.