pictures of the same person drawn in different periods of his life.

It is necessary, therefore, that before an author be charged with
plagiarism, one of the most reproachful, though, perhaps, not the most
atrocious of literary crimes, the subject on which he treats should be
carefully considered. We do not wonder, that historians, relating the
same facts, agree in their narration; or that authors, delivering the
elements of science, advance the same theorems, and lay down the same
definitions: yet it is not wholly without use to mankind, that books are
multiplied, and that different authors lay out their labours on the same
subject; for there will always be some reason why one should on
particular occasions, or to particular persons, be preferable to
another; some will be clear where others are obscure, some will please
by their style and others by their method, some by their embellishments
and others by their simplicity, some by closeness and others by
diffusion.

The same indulgence is to be shown to the writers of morality: right and
wrong are immutable; and those, therefore, who teach us to distinguish
them, if they all teach us right, must agree with one another. The
relations of social life, and the duties resulting from them, must be
the same at all times and in all nations: some petty differences may be,
indeed, produced, by forms of government or arbitrary customs; but the
general doctrine can receive no alteration.

Yet it is not to be desired, that morality should be considered as
interdicted to all future writers: men will always be tempted to deviate
from their duty, and will, therefore, always want a monitor to recall
them; and a new book often seizes the attention of the publick, without
any other claim than that it is new. There is likewise in composition,
as in other things, a perpetual vicissitude of fashion; and truth is
recommended at one time to regard, by appearances which at another would
expose it to neglect; the author, therefore, who has judgment to discern
the taste of his contemporaries, and skill to gratify it, will have
always an opportunity to deserve well of mankind, by conveying
instruction to them in a grateful vehicle.

There are likewise many modes of composition, by which a moralist may
deserve the name of an original writer: he may familiarize his system by
dialogues after the manner of the ancients, or subtilize it into a
series of syllogistick arguments: he may enforce his doc