 If this shows some development by acknowledging the independent role of matter in causation and explanation, it is also likely to appear retrograde in its basic appeal to the apparatus of formal causation. Indeed, in Metaphysical Disputations XV Suárez takes up in detail a question about substantial forms which has a special resonance because of the contumely poured on this doctrine by philosophers writing in the centuries after his death, many of whom were self-consciously concerned to distance themselves from the entire idea of formal causation—a doctrine they regarded as noxious, obscurantist, and explanatorily vacuous. Locke, for instance, in his Essay Concerning Human Understanding, derided his predecessors for their “fruitless Enquiries after substantial Forms, wholly unintelligible, and whereof we have scarce so much as any obscure, or confused Conception in general.” (Locke 1976 [1690]:  3.6.10)[13] 