to anything of which I had no certain knowledge, especially in the
first pages of a work in which I aim at laying down the principles
of truth. And the generous modesty that is conspicuous in all your
actions, assures me that the frank and simple judgment of a man who
only writes what he believes will be more agreeable to you than the
ornate laudations of those who have studied the art of compliment.
For this reason, I will give insertion to nothing in this letter for
which I have not the certainty both of experience and reason; and in
the exordium, as in the rest of the work, I will write only as
becomes a philosopher. There is a vast difference between real and
apparent virtues; and there is also a great discrepancy between
those real virtues that proceed from an accurate knowledge of the
truth, and such as are accompanied with ignorance or error. The
virtues I call apparent are only, properly speaking, vices, which,
as they are less frequent than the vices that are opposed to them,
and are farther removed from them than the intermediate virtues, are
usually held in higher esteem than those virtues. Thus, because
those who fear dangers too much are more numerous than they who fear
them too little, temerity is frequently opposed to the vice of
timidity, and taken for a virtue, and is commonly more highly
esteemed than true fortitude. Thus, also, the prodigal are in
ordinary more praised than the liberal; and none more easily acquire
a great reputation for piety than the superstitious and
hypocritical. With regard to true virtues, these do not all proceed
from true knowledge, for there are some that likewise spring from
defect or error; thus, simplicity is frequently the source of
goodness, fear of devotion, and despair of courage. The virtues that
are thus accompanied with some imperfections differ from each other,
and have received diverse appellations. But those pure and perfect
virtues that arise from the knowledge of good alone are all of the