  Two further points are of particular importance in Du Châtelet's discussion of first principle of knowledge. The first is her noting that the term “principle” “has been much abused”, especially by “the Scholastics, who could demonstrate nothing [and who] chose unintelligible words for their principles” (IP §1, p. 125). The PSR, she later tells us, banishes these unintelligible principles such as “plastic natures, vegetative souls” (IP §10, p. 131). Without detailing how the PSR might banish such other principles, we focus on Du Châtelet's own conception of the sort of intelligible metaphysical principle identified by the PSR, for she favors the mechanical philosophy over, for example, plastic natures and vegetative souls. According to Du Châtelet, one must explain how a mechanism can produce a plant relying, for example, upon an explanation of how each particle of matter is able to produce the effect that it does (IP §10 and §12, p. 131–2) through simple motion. Accounting for natural change by appeal to bits of matter interacting through lawful motion and contact—but not by appeal to plastic natures and vegetative souls—is consistent with the PSR.