called morally necessary, the necessity arising from the fact that, while there is no physical impossibility, yet there is a very great difficulty in acquiring such knowledge as man needs to lead a life worthy of himself and of his Creator. Those who reject revelation are fond of calling themselves "rationalists" , as if they were more rational than other men, while they are so irrational as to refuse additional light when it is offered them; and thus they act most rashly in matters in which the highest interests of man are concerned.
10. When we know a fact or a truth, whether by our natural powers or by revelation, we may still fail to see how the matter can be explained. It is then called a mystery: a natural mystery, if we arrive at the knowledge of its existence by our natural powers; a supernatural mystery, if by revelation only. That the scenes which we have formerly witnessed are recorded in our memory, we know; but how they are there recorded, is a natural mystery; how the three Divine Persons are one God, is a supernatural one. It is absurd for any one to deny that there are natural mysteries; a fortiori, we cannot deny that there are supernatural ones: for the things of God must necessarily be more incomprehensible to us than the sensible things around us. "The things that are of God," says St. Paul, "no man knoweth but the Spirit of God"; and he adds that we have received this Spirit, ' 'that we may know the things that are given us from God" (i Cor. II, n, 12). We have then no right to refuse acceptance of a revelation, on the plea that it contains mysteries.
