5. The safest use of Probabilism is in the field of property transactions and of positive law. There is greatest risk of using it amiss in remaining in a false religion. All turns upon the varying amount of trouble involved in _moral diligence_ of enquiry, according as the matter at issue is a point of mere observance or of vital interest. 6. The point on which the probability turns must be the lawfulness or unlawfulness of the action, not any other issue, as that of the physical consequences. Before rolling boulder-stones down a hill to amuse myself, it is not enough to have formed a probable opinion that there is no one coming up. That would be Probabilism misapplied. The correct enquiry is: Does any intrinsic reason or extrinsic authority make the opinion probable, that it is lawful for mere amusement to roll down rocks with any belief short of certainty that no one will be crushed thereby? The probability, thus turned on to the lawfulness of the action, breaks down altogether. This explanation, borne in mind, will save much misapprehension. CHAPTER IX. OF THE SANCTION OF THE NATURAL LAW. SECTION I.--_Of a Twofold Sanction, Natural and Divine_. 1. The sanction of a law is the punishment for breaking it. The punishment for final, persistent breach of the natural law is failure to attain the perfect state and last end of the human soul, which is happiness. If existence be prolonged under this failure, it must be in the contrary state of misery. This failure and misery is at once a _natural result_ and a _divine infliction_. It is the natural result of repeated flagrant acts of moral evil, whereby a man has made his nature hideous, corrupted and overthrown it. (c. vi., s. i., nn. 4, 5, p. 111.) For an end is gained by taking the means, and lost by neglect of the means thereto. Now, as we have seen, happiness is an intellectual act, the perfection of an intellectual or rational nature (c. ii., s. ii., p. 6); and the means to it are living rationally: for a reasonable being, to do well and fare well, must live by that reason, which is the _form_ of his being. (c. vi., s. i., n. 4, p. 111.) Whoever therefore goes about contradicting the reason that is within him (c. v., s. iii., n. 3, p. 74) is not in the way to attain to happiness. Happiness the end of man, the creature of all others the most complex, is not to be stumbled upon by chance. You may make two stones lean upright one against the other by chance, but otherwise than by a methodical application of means to the end you could not support the spire of Salisbury Cathedral.