John Thomas, a 19th-century religious figure whose writings I have studied (see Listing of Articles on Christadelphian Issues), wrote the following in a letter written just before his death in March 1871, touching upon some of the problems of metaphysics and the appeals thereto in theology:
You will excuse me, perhaps, just reminding you here that metaphysics are of a very unsubstantial and shadowy nature. As a system, it is a science so-called that treats of things immaterial, and, therefore, intangible and ethereal, or visionary; and which may be considered quite beyond the sphere of all profitable enquiry by plain, unphilosophical men, whose faith is based upon the revealed testimony of God, and not upon the modus in quo, or manner in which essences are generated; and how entities and quiddities* are induced. We can believe the testimony of John, that Deity can of stones raise up children to Abraham, with a true and valid faith, which is not at all impaired by our metaphysical inability to explain the process by which he is able to arrive at such a result; for the faith which saves men is the belief of testimony divinely given, not a metaphysical or scientific comprehension of processes. Metaphysics are capital things for ‘doubtful disputation,’ and admirably adapted to the development of ‘sounding brass and tinkling cymbals.’ Let our friends, therefore, who would grow in the knowledge of God and in His favour, eschew metaphysics, by which they can be neither enlightened nor improved; for, as they say in Scotland, which has been befuddled and befooled by the science falsely so-called: “Metaphysics, is when twa men talk thegither, and the ane who hears dinna ken what the ither says; and the ane who speaks dinna ken what he says himsel.”(John Thomas, “What is ‘Flesh?’”)