 It is hardly surprising then to find that Boyle wrote quite extensively on the relation between experimental philosophy and speculative philosophy and on the usefulness of reason to the experimental philosopher. For example, in a catalogue of his unpublished works dating from 1684 there is listed a work entitled “Of Usefulnes of Speculative &amp; Experimental Philosophy to one another” (BW, 14:342). Unhappily this work is no longer extant.