“See physic beg the Stagyrite’s defence,
See metaphysic call for aid on sense.”—Pope.
This usage, however, is not general.
Metaphysics is used both as a singular and plural noun.
“Metaphysics has been defined, by a writer deeply read in the ancient philosophy, ‘The science of the principles and causes of all things existing.’”—Encyc. Brit. Here the word is used as singular; as likewise in the following example:
“Metaphysics has been represented by painters and sculptors as a woman crowned and blindfolded, holding a sceptre in her hand, and having at her feet an hour-glass and a globe.”
“Metaphysics is that science, in which are understood the principles of other sciences.”—Hutton.
In the following examples it is construed as a plural noun.
“Metaphysics tend only to benight the understanding in a cloud of its own making.”—Knox.
“Here, indeed, lies the justest and most plausible objection against a considerable part of metaphysics, that they are not properly a science.”—Hume.