existence, or in the language of grammarians three kinds of verbs. First,
simply I am, or exist. Secondly, I am acting, or exist in a state of
activity, as I move. Thirdly, I am suffering, or exist in a state of being
acted upon, as I am moved. The when, and the where, as applicable to this
existence, depends on the successive motions of our own or of other bodies;
and on their respective situations, as spoken of Sect. XIV. 2. 5.

5. Our identity is known by our acquired habits or catenated trains of
ideas and muscular motions; and perhaps, when we compare infancy with old
age, in those alone can our identity be supposed to exist. For what else is
there of similitude between the first speck of living entity and the mature
man?--every deduction of reasoning, every sentiment or passion, with every
fibre of the corporeal part of our system, has been subject almost to
annual mutation; while some catenations alone of our ideas and muscular
actions have continued in part unchanged.

By the facility, with which we can in our waking hours voluntarily produce
certain successive trains of ideas, we know by experience, that we have
before reproduced them; that is, we are conscious of a time of our
existence previous to the present time; that is, of our identity now and
heretofore. It is these habits of action, these catenations of ideas and
muscular motions, which begin with life, and only terminate with it; and
which we can in some measure deliver to our posterity; as explained in
Sect. XXXIX.

6. When the progressive motions of external bodies make a part of our
present catenation of ideas, we attend to the lapse of time; which appears
the longer, the more frequently we thus attend to it; as when we expect
something at a certain hour, which much interests us, whether it be an
agreeable or disagreeable event; or when we count the passing seconds on a