The second fundamental principle is that the inherent right of access to the earth is conditioned upon, and becomes actually valid through, the expenditure of useful labour. Generally speaking the fruits and potentialities of the earth do not become available to men without previous exertion. "In the sweat of thy brow thou shalt eat thy bread," is a physical no less than a moral commandment. There are, indeed, exceptions: the very young, the infirm, and the possessors of a sufficient amount of property. The two former classes have claims to a livelihood through piety and charity, while the third group has at least a presumptive claim of justice to rent and interest, and a certain claim of justice to the money value of their goods. Nevertheless, the general condition is that men must work in order to live. "If a man will not work neither shall he eat." For those who refuse to comply with this condition the inherent right of access to the earth remains only hypothetical and suspended. The two foregoing principles involve as a corollary a third principle; the men who are in present control of the opportunities of the earth are obliged to permit reasonable access to these opportunities by persons who are willing to work. In other words, possessors must so administer the common bounty of nature that non-owners will not find it unreasonably difficult to get a livelihood. To put it still in other terms, the right to subsist from the earth implies the right to access thereto on reasonable terms. When any man who is willing to work is denied the exercise of this right, he is no longer treated as the moral and juridical equal of his fellows. He is regarded as inherently inferior to them, as a mere instrument to their convenience; and those who exclude him are virtually taking the position that their rights to the common gifts of the Creator are inherently superior to his birthright. Obviously this position cannot be defended on grounds of reason. Possessors are no more justified in excluding a man from reasonable access to the goods of the earth than they would be in depriving him of the liberty to move from place to place. The community that should arbitrarily shut a man up in prison would not violate his rights more fundamentally than the community or the proprietors who should shut him out from the opportunity of getting a livelihood from the bounty of the earth. In both cases the man demands and has a right to a common gift of God. His moral claim is as valid to the one good as to the other, and it is as valid to both goods as is the claim of any of his fellows. _The Right to a Decent Livelihood_