He began, therefore, by a preliminary article on the actual state of created things--that is, the material, so to say, out of which private property is evolved. Here he notes that the nature of things, their constituent essence, is in the hands of God, not man. The worker can change the form, and, in consequence, the value of a thing, but the substance which lies beneath all the outward show is too subtle for him to affect it in any way. To the Supreme Being alone can belong the power of creation, annihilation, and absolute mutation. But besides this tremendous force which God holds incommunicably, there is another which He has given to man, namely, the use of created things. For when man was made, he was endowed with the lordship of the earth. This lordship is obviously one without which he could not live. The air, and the forces of nature, the beasts of the field, the birds and fishes, the vegetation in fruit and root, and the stretches of corn are necessary for man's continued existence on the earth. Over them, therefore, he has this limited dominion. Moreover, St. Thomas goes on, man has not merely the present moment to consider. He is a being possessed of intelligence and will, powers which demand and necessitate their own constant activity. Instinct, the gift of brute creation, ensures the preservation of life by its blind preparation for the morrow. Man has no such ready-made and spontaneous faculty. His powers depend for their effectiveness on their deliberative and strenuous exertions. And because life is a sacred thing, a lamp of which the once extinguished light cannot be here re-enkindled, it carries with it, when it is intelligent and volitional, the duty of self-preservation. Accordingly the human animal is bound by the law of his own being to provide against the necessities of the future. He has, therefore, the right to acquire not merely what will suffice for the instant, but to look forward and arrange against the time when his power of work shall have lessened, or the objects which suffice for his personal needs become scarcer or more difficult of attainment. Property, therefore, of some kind or other, says Aquinas, is required by the very nature of man. Individual possessions are not a mere adventitious luxury which time has accustomed him to imagine as something he can hardly do without, nor are they the result of civilised culture, which by the law of its own development creates fresh needs for each fresh demand supplied; but in some form or other they are an absolute and dire necessity, without which life could not be lived at all. Not simply for his "well-being," but for his very existence, man finds them to be a sacred need. Thus as they follow directly from the nature of creation, we can term them "natural."