Those, then, are the principal kinds of change, as analysed by Aristotle and the scholastics. We may note, finally, that the distinction between _immanent_ and _transitive_ activity is also applied to change—that is, to change considered as a process, not to the result of the change, to change _in fieri_, not _in facto esse_. Immanent movement or activity (_motio_, _actio immanens_) is that of which the term, the educed actuality, remains within the agent—which latter is therefore at once both _agens_ and _patiens_. Vital action is of this kind. Transitive movement or activity, on the other hand (_motio_, _actio transiens_), is that of which the term is some actuality educed in a being other than the agent. The _patiens_ is here really distinct from the _agens_; and it is in the former, not in the latter, that the change takes place: _actio fit in passo_. All change in the inorganic universe is of this sort (101). CHAPTER III. EXISTENCE AND ESSENCE. 12. EXISTENCE.—In the preceding chapters we examined reality in itself and in its relation to change or becoming. We have now to examine it in relation to its actual existence and to its intrinsic possibility (7, _a_). _Existing_ or _being_ (in the participial sense: esse, _existere_, τὸ εἶναι) is a simple, indefinable notion. A being is said to exist when it is not merely possible but actual, when it is not merely potential in its active and passive causes but has become actual through those causes (_existere_: _ex-sisto_: _ex-stare_: to stand forth, distinct from its causes); or, if it have no causes, when it simply is (_esse_),—in which sense God, the Necessary, purely Actual Being, simply _is_. Thus, existence implies the notion of actuality, and is conceived as that by which any thing or essence _is, distinct from nothingness, in the actual order_.(83) Or, again, it is _the actuality of any thing or essence_. About any conceivable being we may ask two distinct questions: (_a_) What is it? and (_b_) Does such a being actually exist? The answer to the former gives us the _essence_, what is presented to the mind through the concept; the answer to the latter informs us about the actual _existence_ of the being or essence in question.