And, although, the best among the philosophers held that the end of human life is the contemplation of Divine things, their teaching on this point is very confused, because they cannot speak, with any certainty, about their end. If they were asked, whether, by this contemplation, they meant contemplation of this present life, or of the future life, they could not answer with any certainty. For, considering the perils and troubles of this life, it would be wholly unreasonable to expect beatitude in it; and as the philosophers could not, by means of mere natural reason, discover anything about the future life, whatever they might say about it would be unproven, and therefore not accepted by men. They would, furthermore, involve themselves in the still more intricate question of the immortality of the soul, the difficulty of which is shown by the many different opinions entertained concerning it. The greatest difficulty on this point arises from the fact, that, as the soul can perform the operation of understanding without any corporeal organ, it would appear, that, with regard to the activity of understanding, the soul cannot be the form of the body; for it seems as if that which can act without a body, can exist without a body. This is why Plato insisted that our soul is not the form, but the mover of the human body.
Aristotle, on the contrary, maintains that the soul is the form of the body. He, however, uses such ambiguous expressions about the understanding, as distinct from the soul, that his commentator, Averröes, fell into the unreasonable error of supposing that there is in all men an intellect, existing independently of other powers. But, I believe that Aristotle, being a very sagacious man and knowing that the natural light of reason cannot arrive at any perfect knowledge of the matter, purposely spoke very cautiously about it, for fear of being worsted in argument. Thus the philosophers who followed him, remained in a dilemma. For, if they called the soul the form of the body, it seemed that the soul must reasonably be supposed to be mortal. If they said that the soul was not the form of the body, it was impossible to see how man could be said to be man, on account of his possessing an intellectual soul. And, if, with no clearer light than the light of natural reason, they had maintained what Faith teaches, viz., that although the intellectual power of the soul operates independently of any corporeal organ, yet, nevertheless, the substance of the soul is the form of the body, they would have found themselves in quite as great a difficulty as they were before. For they would have been asked, whence came this form—a question to which they could have given no certain answer. For, as this form is elevated above all corporeal things, it cannot have been produced by any natural power; nor, as they did not believe in creation, would these philosophers have said that it came from nothing. And, even if they had made such an assertion, they could not have produced any reasonable proof of what they said. Their opinion, consequently, would have been treated with contempt.
Certain ones amongst them, therefore, endeavoured to evade the difficulty, by maintaining that souls existed from eternity, before bodies. This opinion, however, involved them in still greater confusion. For, while they held that souls were made from eternity before bodies, they could adduce no reason to hinder the soul from being the form of the body. They, also, at the same time, fell into many other inconsistencies, adduced by the Peripatetics against the Platonists. And, although Aristotle said that the intellectual soul comes from without, i.e., not from natural power,—his expression is very ambiguous; for it explains neither whence, nor how, the soul comes into the world. And if, as he maintains, the intellectual soul be immortal, and the form of the body, it cannot, at the same time, exist before the body, nor pass from one body to another. Therefore, if the soul be not produced by natural power, I do not see how Aristotle can deny Creation.
The philosophers who, unenlightened by faith, assert that the soul is immortal, and is the form of the body, expose themselves to further difficulties. They may, with good reason, be asked whether the world has likewise existed from eternity, and whether it will last for ever. If they reply, without being able to prove their words, that the world had a beginning and will have an end, their views will be held in derision. If, on the other hand, with Aristotle, they maintain that the world never had a beginning and will never have an end, they must likewise hold that there has existed an infinite series of years and days. But, if man is the most important part of the world, no one can, with any show of reason, say that the world has existed without man; and therefore infinite men must have died. If, further, as they say, the soul is immortal, and is the form of the body; and if it does not pass from one body to another, there must have been infinite souls. This is, clearly, an irrational hypothesis. Those who uphold this view will, of course, maintain that it is not irrational; but by so doing, they have to face fresh difficulties. For, as the soul is the form of the body, it is against its nature to be outside the body; and we know, in fact, that the soul only leaves the body by compulsion. Now, compulsion, or violence, cannot continue perpetually, especially in the case of so noble a thing as the soul.
Those, however, who hold that souls will never return to their bodies, must admit that souls, in spite of their dignity, are perpetually banished, by violence, from their bodies. If they believe in the resurrection of the body, on the other hand, they must believe in the resurrection of infinite bodies, which is impossible. They may, indeed, hold, that, after a certain prolonged space of time, souls will return to their former bodies, and will become what they formerly were; and that they will repeat this separation from, and return to, their bodies an infinite number of times. But they have no reason, or proof, on which to ground this hypothesis; and we are right in treating it with contempt. And, certainly, such a supposition is unreasonable and absurd, implying, as it does, that we, and all that exist at present, must have already existed an infinite number of times.
In these, and in such like difficulties, do they entangle themselves who try, by natural reason, to discover the end of human life. Nor, as they ignore the most important element of life, can they be expected to speak surely or definitely, either about religion or about virtuous living. We need not, therefore, be surprised, that the religious systems of the philosophers are imperfect, and filled with error.
We shall understand this fact still more clearly, if we consider the different erroneous conclusions at which they have arrived; and we shall see how poor and feeble a thing is the unassisted light of reason. The highest power of an agent is shown when it exerts itself to its fullest capacity. Now, human reason has been most strenuously exerted by the greatest philosophers, who have exercised it to the utmost of their ability. We see this by the fact, that the other philosophers who have succeeded them, have never found anything new to say; or if they have originated some fresh theory, it has been a very insignificant one. Since, then, the very greatest philosophers have been so grossly mistaken in matters concerning salvation, it is evident that the natural light of reason is but a treacherous guide.
Of course, the earliest philosophers, who asserted that the last end of man is to be found in riches, glory, pleasure, or some other material good, were far more completely deceived than those who taught that it was to be sought in the contemplation of Divine things. But, the teaching of these latter was vague, and left men in the greatest uncertainty about the affairs of their salvation.
Again, there are as many opinions and errors about the nature of the intellectual soul, as there are philosophers. Setting aside the fallacies enumerated by Aristotle in his first book, De Anima, even the Aristotelian philosophers themselves entertain endless different views. Some teach that the human understanding is one thing, and others proclaim it to be another; so that, even to this day, their disciples remain in utter uncertainty. This confusion would be even more inextricable, had not the Faith of Christ enlightened the world.
Again, if any one will read the philosophical books treating of the universe, of the end for which it was made, and of its supposed beginning and end, he will find almost as many errors as there are words. And, although Aristotle, and some of his followers, have tried to establish the eternity of the world, the Aristotelian arguments are so weak, that any learned man could easily overthrow them.