Lastly, the mode of being which results from the accidental actuation of the subject is only an accidentality, or an accidental actuality, as we have already remarked, and is predicated of the subject, not as something _received_ in it, but as something following from the actual reception of the accidental act. Hence the substance, or the nature, which is the subject of such accidental modes lies under them, not on account of its receptivity, but on account of the resulting potentiality, which is a proper appurtenance, not of the material term, but of the formal complement of the substance. And, in fact, the complement of all created essence always arises from the actuation of a potential term, and therefore is itself necessarily potential—that is, liable to such accidental changes as may result from any new actuation of the essential term. This resulting potentiality is commonly styled _mobility_, _changeableness_, or _affectibility_, and may be called _modal_ potentiality in opposition to the _passive_ potentiality which is the characteristic of the essential term. Hence a subject is said to _receive_ the accidental act, but not the accidental mode; and, on the contrary, is said to _be affected_ by the accidental mode, but not by the accidental act. We may say, however, that a subject _is modified_ as well by the act as by the mode, because this expression applies equally to the making of the change (_mutatio in fieri_) and to the state that follows (_mutatio in facto esse_). A subject has, therefore, two distinct manners of _underlying_: the one on account of its receptivity, the other on account of its affectibility; the one by reason of the _passive_ potentiality of its term, the other by reason of the _modal_ potentiality of its complement. Thus a body, according to its passive potentiality, underlies the _act_ produced in it by a motive power, because it passively receives the motive determination, and, according to its modal potentiality, it underlies _local movement_, this movement being the immediate result of the determination received. And in a similar manner our soul, inasmuch as it is receptive or passive, underlies the act produced or the impression made in it by a cognizable object; and inasmuch as it is affectible, it underlies the feeling or affective movement, which immediately results from the cognition of the object.