incommodious revulsion, a troublesome distaste, when it is endeavoured
to make him change the course of his ideas: a fatal predilection
frequently conducts him back to the old track in despite of reason.

It is by a pure mechanism that may be explained the phenomena of habit,
as well physical as moral; the soul, notwithstanding its spirituality,
is modified exactly in the same manner as the body. Habit, in man,
causes the organs of voice to learn the mode of expressing quickly the
ideas consigned to his brain, by means of certain motion, which, during
his infancy, the tongue acquires the power of executing with facility:
his tongue, once habituated to move itself in a certain manner, finds
much trouble, has great pain, to move itself after another mode; the
throat yields with difficulty to those inflections which are exacted by
a language different from that to which he has, been accustomed. It is
the same with regard to his ideas; his brain, his interior organ, his
soul, inured to a given manner of modification, accustomed to attach
certain ideas to certain objects, long used to form to itself a system
connected with certain opinions, whether true or false, experiences a
painful sensation, whenever he undertakes to give it a new impulse, or
alter the direction of its habitual motion. It is nearly as difficult to
make him change his opinions as his language.

Here, then, without doubt, is the cause of that almost invincible
attachment which man displays to those customs--those prejudices--those
institutions of which it is in vain that reason, experience, good sense
prove to him the inutility, or even the danger. Habit opposes itself to
the clearest, the most evident demonstrations; these can avail nothing
against those passions, those vices, which time has rooted in him--
against the most ridiculous systems--against the most absurd notions--
against the most extravagant hypotheses--against the strangest customs: