Herbert Feigl, The "Mental" and the "Physical": The Essay and a Postscript (1967).
IV. Sorting Out the Various Meanings of "Mental" and "Physical". A Comparative and Critical Analysis
Much of the trouble with the mind-body problem arises out of the ambiguities and vaguenesses of the terms "mental" and "physical". Some of their connotations have been briefly indicated in the juxtapositions listed toward the end of the preceding section. I shall now attempt to analyze these and other meanings more closely, and to point out the merits and demerits of the various actual and possible usages of "mental" and "physical". Philosophers of the modern age clearly differ as to what constitutes the central core or (if there be such clarity!?) the criteria of the mental and the physical. Some philosophers fasten primarily upon one pair of distinctions, others on a different pair as of primary significance.