It is according to this standard, that the principles laid down in this work, ought to be judged. Those who are acquainted with the immense chain of mischief produced on the earth by erroneous systems of superstition, will acknowledge the importance of opposing to them systems more accordant with truth, schemes drawn from Nature, sciences founded on experience. Those who are, or believe they are, interested in maintaining the established errors, will contemplate, with horror, the truths here presented to them: in short, those infatuated mortals, who do not feel, or who only feel very faintly, the enormous load of misery brought upon mankind by metaphysical speculation; the heavy yoke of slavery under which prejudice makes him groan, will regard all our principles as useless; or, at most, as sterile truths, calculated to amuse the idle hours of a few speculators. No astonishment, therefore, need be excited at the various judgments formed by man: his interests never being the same, any more than his notions of utility, he condemns or disdains every thing that does not accord with his own peculiar ideas. This granted, let us examine, if in the eyes of the disinterested man, who is not entangled by prejudice--who is sensible to the happiness of his species--who delights in truth--the _doctrine of fatalism_ be useful or dangerous? Let us see if it is a barren speculation, that his not any influence upon the felicity of the human race? At has been already shewn, that it will furnish morals with efficacious arguments, with real motives to determine the will, supply politics with the true lever to raise the proper activity in the mind of man. It will also be seen that it serves to explain in a simple manner the mechanism of man's actions; to develope in an easy way the arcana of the most striking phenomena of the human heart: on the other hand, if his ideas are only the result of unfruitful speculations, they cannot interest the happiness of the human species. Whether he believes himself a free agent, or whether he acknowledges the necessity of things, he always equally follows the desires imprinted on his soul; which are to preserve his existence and render himself happy. A rational education, honest habits, wise systems, equitable laws, rewards uprightly distributed, punishments justly inflicted, will conduct man to happiness by making him virtuous; while thorny speculations, filled with difficulties, can at most only have an influence over persons unaccustomed to think. After these reflections, it will be very easy to remove the difficulties that are unceasingly opposed to the system of fatalism, which so many persons, blinded by their superstitious prejudices, are desirous to have considered as dangerous--as deserving of punishment--as calculated to disturb public tranquility--as tending to unchain the passions--to undermine the opinions man ought to have; and to confound his ideas of vice and of virtue.