sions of the muscles,
as in epileptic fits, may in the common sense of that word be termed
involuntary; because no deliberation is interposed between the desire or
aversion and the consequent action; but in the sense of the word, as above
defined, they belong to the class of voluntary motions, as delivered in
Vol. II. Class III. If this use of the word be discordant to the ear of the
reader, the term morbid voluntary motions, or motions in consequence of
aversion, may be substituted in its stead.

If a person has a desire to be cured of the ague, and has at the same time
an aversion (or contrary desire) to swallowing an ounce of Peruvian bark;
he balances desire against desire, or aversion against aversion; and thus
he acquires the power of choosing, which is the common acceptation of the
word _willing_. But in the cold fit of ague, after having discovered that
the act of shuddering, or exerting the subcutaneous muscles, relieves the
pain of cold; he immediately exerts this act of volition, and shudders, as
soon as the pain and consequent aversion return, without any deliberation
intervening; yet is this act, as well as that of swallowing an ounce of the
bark, caused by volition; and that even though he endeavours in vain to
prevent it by a weaker contrary volition. This recalls to our minds the
story of the hungry ass between two hay-stacks, where the two desires are
supposed so exactly to counteract each other, that he goes to neither of
the stacks, but perishes by want. Now as two equal and opposite desires are
thus supposed to balance each other, and prevent all action, it follows,
that if one of these hay-stacks was suddenly removed, that the ass would
irresistibly be hurried to the other, which in the common use of the word
might be called an involuntary act; but which, in our acceptation of it,
would be classed amongst voluntary actions, as above explained.

Hence to deliberate is to compare opposing desires or aversions, and that
which is the most interesting at length prevails, and produces action.
Similar to this, where two pains oppose each other, the stronger or more
interesting one produces action; as in pleurisy the pain from suffocation
would produce expansion of the lungs, but the pain occasioned by extending
the inflamed membrane, which lines the chest, opposes this expansion, and
one or the other alternately prevails.

When any one moves his hand quickly near another person's eyes, the
eye-lids instan