Another great Thomist, Goudin, wishing to prove that in all creatures the power of acting is an accident, argues that _potentia et actus sunt idem, quamvis diversimode_, and that _actus est semper nobilior quam potentia ad eum essentialiter ordinata_; whence he concludes that, if a given act is an accident, the active power, whence it proceeds, must needs be an accident too. Here, also, the equivocation is evident. The act is _nobilior quam potentia_ when we compare it with the _potentia passiva_ which is destined to receive it--that is, to be actuated by it--but when an act is compared with the active power from which it proceeds--that is, with the _potentia activa_--we cannot say that it is _nobilior quam potentia ad eum essentialiter ordinata_: it is the contrary that is true. Had the author used the word _virtus agendi_ instead of the equivocal word _potentia_, he would soon have discovered the fallacy of his argument. I am sorry to say that even S. Thomas sometimes forgets to observe the distinction between _potentia activa_ and _potentia passiva_; as in the first part of his _Summa_, where he compares the _potentia essendi_ and the _potentia operandi_ with their respective acts, and establishes a kind of proportion between the two potencies and the two acts.[70] No such proportion can be admitted, unless the _potentia operandi_ and the _potentia essendi_ are both similarly connected with their acts. Yet whilst the _potentia operandi_ is active, the _potentia essendi_, according to S. Thomas, is passive.[71] They cannot, therefore, be related to their acts in a similar manner. Hence, the terms are not homologous, and the proportion cannot subsist. In another place, the holy doctor argues that, if an act is accidental, the _potentia_ from which it proceeds must be accidental also; because _potentia et actus dividunt ens, et quodlibet genus entis_, and, therefore, _oportet quod ad idem genus referatur potentia et actus_.[72] But the _potentia_ which, with the _actus_, constitutes the being and every class of beings is the _potentia passiva_; whilst the _potentia_ from which any act proceeds is the _potentia activa_. The argument, therefore, contains four terms, and proves one thing only, namely, that it is extremely difficult, even for the greatest men, to avoid equivocations when things that are different and opposite are designated by the same term. In English, the word _potentia_ is commonly represented by "power," to which the epithets of "active" and "passive" have been attached by some writers, in the same manner as was done with the Latin _potentia_. "Power," says Locke,[73] "may be considered twofold, namely, as able to make or able to receive any change." But "in strictness," says Webster, "passive power is an absurdity in terms. To say that gold has a power to be melted is improper language; yet for want of a more appropriate word, _power_ is often used in a passive sense."