Beneficial tendency is the foundation of rules, and the criterion by which habits and sentiments are to be tried. But it is neither the immediate standard, nor can it ever be the principal motive of action. An action, to be completely virtuous, must accord with moral rules, and must flow from our natural feelings and affections, moderated, matured, and improved into steady habits of right conduct.[16] Without, however, dwelling longer on subjects which cannot be clearly stated, unless they are fully unfolded, I content myself with observing, that it shall be my object, in this preliminary, but most important part of the course, to lay the foundations of morality so deeply in human nature, as may satisfy the coldest inquirer; and, at the same time, to vindicate the paramount authority of the rules of our duty, at all times, and in all places, over all opinions of interest and speculations of benefit, so extensively, so universally, and so inviolably, as may well justify the grandest and the most apparently extravagant effusions of moral enthusiasm. If, notwithstanding all my endeavours to deliver these doctrines with the utmost simplicity, any of my auditors should still reproach me for introducing such abstruse matters, I must shelter myself behind the authority of the wisest of men. "If they (the ancient moralists), before they had come to the popular and received notions of virtue and vice, had staid a little longer upon the inquiry concerning _the roots of good and evil_, they had given, in my opinion, a great light to that which followed; and specially if they had consulted with nature, they had made their doctrines less prolix, and more profound."--_Bacon. Dign. and Adv. of Learn._ book ii. What Lord Bacon desired for the mere gratification of scientific curiosity, the welfare of mankind now imperiously demands. Shallow systems of metaphysics have given birth to a brood of abominable and pestilential paradoxes, which nothing but a more profound philosophy can destroy. However we may, perhaps, lament the necessity of discussions which may shake the habitual reverence of some men for those rules which it is the chief interest of all men to practise, we have now no choice left. We must either dispute, or abandon the ground. Undistinguishing and unmerited invectives against philosophy, will only harden sophists and their disciples in the insolent conceit, that they are in possession of an undisputed superiority of reason; and that their antagonists have no arms to employ against them, but those of popular declamation. Let us not for a moment even appear to suppose, that philosophical truth and human happiness are so irreconcilably at variance. I cannot express my opinion on this subject so well as in the words of a most valuable, though generally neglected writer: "The science of abstruse learning, when completely attained, is like Achilles's spear, that healed the wounds it had made before; so this knowledge serves to repair the damage