diversity of those effects which they make him experience. It is upon
the necessary diversity of these effects that is founded the
discrimination between good and evil--between virtue and vice;
distinctions which do not rest, as some thinkers have believed, on the
conventions made between men; still less, as some metaphysicians have
asserted, upon the chimerical will of supernatural beings: but upon the
solid, the invariable, the eternal relations that subsist between beings
of the human species congregated together, and living in society: which
relations will have existence as long as man shall remain, as long as
society shall continue to exist.

Thus _virtue_ is every thing that is truly beneficial, every thing that
is constantly useful to the individuals of the human race, living
together in society; _vice_ every thing that is really prejudicial,
every thing that is permanently injurious to them. The greatest virtues
are those which procure for man the most durable advantages, from which
he derives the most solid happiness, which preserves the greatest degree
of order in his association: the greatest vices, are those which most
disturb his tendency to happiness, which perpetuate error, which most
interrupt the necessary order of society.

The _virtuous man_, is he whose actions tend uniformly to the welfare,
constantly to the happiness, of his fellow creatures. The _vicious man_,
is he whose conduct tends to the misery, whose propensities form the
unhappiness of those with whom he lives; from whence his own peculiar
misery most commonly results.

Every thing that procures for a man true and permanent happiness is
reasonable; every thing that disturbs his individual felicity, or that
of the beings necessary to his happiness, is foolish and unreasonable.