If everything is necessary, if errors, opinions, and ideas of men are
fated, how or why can we pretend to reform them? The errors of men are
the necessary results of their ignorance; their ignorance, their
obstinacy, their credulity, are the necessary results of their
inexperience, of their indifference, of their lack of reflection; the
same as congestion of the brain or lethargy are the natural effects of
some diseases. Truth, experience, reflection, reason, are the proper
remedies to cure ignorance, fanaticism, and follies; the same as
bleeding is good to soothe congestion of the brain. But you will say,
why does not truth produce this effect upon many of the sick heads?
There are some diseases which resist all remedies; it is impossible to
cure obstinate patients who refuse to take the remedies which are given
them; the interest of some men and the folly of others naturally oppose
them to the admission of truth. A cause produces its effect only when it
is not interrupted in its action by other causes which are stronger, or
which weaken the action of the first cause or render it useless. It is
entirely impossible to have the best arguments accepted by men who are
strongly interested in error; who are prejudiced in its favor; who
refuse to reflect; but it must necessarily be that truth undeceives the
honest souls who seek it in good faith. Truth is a cause; it produces
necessarily its effect when its impulse is not interrupted by causes
which suspend its effects.