Zeno's definition, then, is this: "A perturbation" (which he calls
a [Greek: pathos]) "is a commotion of the mind repugnant to reason, and
against nature." Some of them define it even more briefly, saying that
a perturbation is a somewhat too vehement appetite; but by too vehement
they mean an appetite that recedes further from the constancy of
nature. But they would have the divisions of perturbations to arise
from two imagined goods, and from two imagined evils; and thus they
become four: from the good proceed lust and joy--joy having reference
to some present good, and lust to some future one. They suppose fear
and grief to proceed from evils: fear from something future, grief from
something present; for whatever things are dreaded as approaching
always occasion grief when present. But joy and lust depend on the
opinion of good; as lust, being inflamed and provoked, is carried on
eagerly towards what has the appearance of good; and joy is transported
and exults on obtaining what was desired: for we naturally pursue those
things that have the appearance of good, and avoid the contrary.
Wherefore, as soon as anything that has the appearance of good presents
itself, nature incites us to endeavor to obtain it. Now, where this
strong desire is consistent and founded on prudence, it is by the
Stoics called [Greek: boulesis], and the name which we give it is
volition; and this they allow to none but their wise man, and define it
thus: Volition is a reasonable desire; but whatever is incited too
violently in opposition to reason, that is a lust, or an unbridled
desire, which is discoverable in all fools. And, therefore, when we are
affected so as to be placed in any good condition, we are moved in two
ways; for when the mind is moved in a placid and calm motion,
consistent with reason, that is called joy; but when it exults with a
vain, wanton exultation, or immoderate joy, then that feeling may be
called immoderate ecstasy or transport, which they define to be an
elation of the mind without reason. And as we naturally desire good
things, so in like manner we naturally seek to avoid what is evil; and
this avoidance of which, if conducted in accordance with reason, is
called caution; and this the wise man alone is supposed to have: but
that caution which is not under the guidance of reason, but is attended
with a base and low dejection, is called fear. Fear is, therefore,
caution destitute of reason. But a wise man is not affe