The refutation of the Manichean hypothesis is extremely easy if we be permitted to assume that both the principles which it supposes are either of infinite power or of equal power. If they are of infinite power, the supposition of their co-existence involves a contradiction in terms; for the one being in opposition to the other, the power of each must be something taken from that of the other; consequently neither can be of infinite power. If, again, we only suppose both to be of equal power, and always acting against each other, there could be nothing whatever done, neither good or evil; the universe would be at a standstill; or rather no act of creation could ever have been performed, and no existence could be conceived beyond that of the two antagonistic principles.
Archbishop Tillotson’s argument, properly speaking, amounts to this last proposition, and is applicable to equal and opposite principles, although he applies it to two beings, both infinitely powerful and counteracting one another. When he says they would tie up each other’s bands, he might apply this argument to such antagonistic principles if only equal, although not infinitely powerful. The hypothesis of their being both infinitely powerful needs no such refutation; it is a contradiction in terms. But it must be recollected that the advocates of the Manichean doctrine endeavor to guard themselves against the attack by contending, that the conflict between the two principles ends in a kind of compromise, so that neither has it all his own way; there is a mixture of evil admitted by the good principle, because else the whole would beat a standstill; while there is much good admitted by the evil principle, else nothing, either good or evil, would be done. Another answer is therefore required to this theory than what Tillotson and his followers have given.
_First_, we must observe that this reasoning of the Manicheans proceeds upon the analogy of what we see in mortal contentions; where neither party having the power to defeat the other, each is content to yield a little to his adversary, and so, by mutual concession, both are successful to some extent, and both to some extent disappointed. But in a speculation concerning the nature of the Deity, there seems no place for such notions.