The supposed want of success attending the labours of the past, is, no doubt, the principal reason which has induced so many to abandon the problem of evil in despair, and even to accuse of presumption every speculation designed to shed light upon so great a mystery. But this reason, however specious and imposing at first view, will lose much of its apparent force upon a closer examination.

In every age the same reasoning has been employed to repress the efforts of the human mind to overcome the difficulties by which it has been surrounded; yet, in spite of such discouragements, the most stupendous difficulties have gradually yielded to the progressive developments and revelations of time. It was the opinion of Socrates, for example, that the problem of the natural world was unavoidably concealed from mortals, and that it was a sort of presumptuous impiety, displeasing to the gods, for men to pry into it. If Newton himself had lived in that age, it is probable that he would have entertained the same opinion. It is certain that the problem in question would then have been as far beyond the reach of his powers, as beyond those of the most ordinary individual. The ignorance of the earth's dimensions, the manifold errors respecting the laws of motion, and the defective state of the mathematical sciences, which then prevailed, would have rendered utterly impotent the efforts of a thousand Newtons to grapple with such a problem. The time was neither ripe for the solution of that problem, nor for the appearance of a Newton. It was only after science had, during a period of two thousand years, multiplied her resources and gathered up her energies, that she was prepared for a flight to the summit of the world, whence she might behold and reveal the wonderful art wherewith it hath been constructed by the Almighty Architect. Because Socrates could not conceive of any possible means of solving the great problem of the material world, it did not follow, as the event has shown, that it was forever beyond the reach and dominion of man. We should not then listen too implicitly to the teachers of despair, nor too rashly set limits to the triumphs of the human power. If we may believe "the master of wisdom," they are not the true friends of science, nor of the world's progress. "By far the greatest obstacle," says Bacon, "to the advancement of the sciences, is to be found in men's despair and idea of impossibility."

Even in the minds of those who cultivate a particular branch of knowledge, there is often an internal secret despair of finding the truth, which so far paralyzes their efforts as to prevent them from seeking it with that deep earnestness, without which it is seldom found. The history of optics furnishes a most impressive illustration of the justness of this remark. Previous to the time of Newton, no one seemed to entertain a real hope that this branch of knowledge would ever assume the form and clearness of scientific truth. The laws and properties of so ethereal a substance as light, appeared to elude the grasp of the human intellect; and hence, no one evinced the boldness to grapple directly with them. The whole region of optics was involved in mists, and those who gave their attention to this department of knowledge, abandoned themselves, for the most part, to vague generalities and loose conjectures. In the conflict of manifold opinions, and the great variety of hypotheses which seemed to promise nothing but endless disputes, the highest idea of the science of optics that prevailed, was that of something in relation to light which might be plausibly advanced and confidently maintained. It was reserved for Newton to produce a revolution in the mode of treating this branch of knowledge, as well as that of physical astronomy. Not despairing of the truth, he sternly put away "innumerable fancies flitting on all sides around him," and by searching observation and experiment, brought his mind directly into contact with things themselves, and held it steadily to them, until the clear light of truth dawned. The consequence was, that the dreams of philosophy, falsely so called, gave place to the clear realities of nature. It was to the unconquerable hope, no less than to the profound humility of Newton, that the world is indebted for his most splendid discoveries, as well as for that perfect model of the true spirit of philosophy, which combined the infinite caution of a Butler with the unbounded boldness of a Leibnitz. The lowliest humility, free from the least shadow of despair, united with the loftiest hope, without the least mixture of presumption, both proceeding from an invincible love of truth, are the elements which constituted the secret of that patient and all-enduring thought which conducted the mind of Newton from the obscurities and dreams enveloping the world below into the bright and shining region of eternal truths above. In our humble opinion, Newton has done more for the great cause of knowledge, by the mighty impulse of hope he has given to the powers of the human mind, than by all the sublime discoveries he has made. For, as Maclaurin says: "The variety of opinions and perpetual disputes among philosophers has induced not a few of late, as well as in former times, to think that it was vain labour to endeavour to acquire certainty in natural knowledge, and to ascribe this to some unavoidable defect in the principles of the science. But it has appeared sufficiently, from the discoveries of those who have consulted nature, and not their own imaginations, and particularly from what we learn from Sir Isaac Newton, that the fault has lain in philosophers themselves, and not in philosophy."

We are persuaded the day will come, when it will be seen that the despair of scepticism has been misplaced, not only with regard to natural knowledge, but also in relation to the great problems of the intellectual and moral world. It is true, that Plato failed to solve these problems; but his failure may be easily accounted for, without in the least degree shaking the foundations of our hope. The learned Ritter has said, that Plato felt the necessity imposed upon him, by his system, to reconcile the existence of evil with the perfections of God; but yet, as often as he approached this dark subject, his views became vague, fluctuating, and unsatisfactory. How little insight he had into it on any scientific or clearly defined principle, is obvious from the fact, that he took shelter from its difficulties in the wild hypothesis of the preexistence of souls. But the impotency of Plato's attempts to solve these difficulties, may be explained without the least disparagement to his genius, or without leading us to hope for light only from the world's possession of better minds.

In the first place, such was the state of mental science when Plato lived, that it would have been impossible for any one to reconcile the existence of evil with the perfections of God. It has been truly said, that "An attention to the internal operations of the human mind, with a view to analyze its principles, is one of the distinctions of modern times. Among the ancients scarcely anything of the sort was known." -- Robert Hall. Yet without a correct analysis of the powers of the human mind, and of the relations they sustain to each other, as well as to external objects and influences, it is impossible to shed one ray of light on the relation subsisting between the existence of moral evil and the divine glory. The theory of motion is "the key to nature." It was with this key that Newton, the great high-priest of nature, entered into her profoundest recesses, and laid open her most sublime secrets to the admiration of mankind. In like manner, the true theory of action is the key to the intellectual world, by which its difficulties are to be laid open and its enigmas solved. Not possessing this key, it was as impossible for Plato, or for any other philosopher, to penetrate the mystery of sin's existence, as it would have been, without a knowledge of the laws of motion, to comprehend the stupendous problem of the material universe.

Secondly, the ancient philosophers laboured under the insuperable disadvantage, that the sublime disclosures of revelation had not been made known to the world. Hence the materials were wanting out of which to construct a Theodicy, or vindication of the perfections of God. For if we could see only so much of this world's drama as is made known by the light of nature, it would not be possible to reconcile it with the character of its great Author. No one was more sensible of this defect of knowledge than Plato himself; and its continuance was, in his view, inconsistent with the goodness of the divine Being. Hence his well-known prediction, that a teacher would be sent from God to clear up the darkness of man's present destiny, and to withdraw the veil from its future glory. The facts of revelation cannot, of course, be logically assumed as verities, in an argument with the atheist; but still, as we shall hereafter see, they may, in connexion with other truths, be made to serve a most important and legitimate function in exploding his sophisms and objections.