Capital

Capital, In the sense of capital value, is simply future income discounted or, in other words, capitalized.The value of any property, or rights to wealth, is its value as a source of income and is found by discounting that expected income.We may, if we so choose, for logical convenience, include as property the ownership in ourselves , or we may , conformably to custom, regard human beings as in a separate category.
(Fisher, Irving. The Theory of Interest, as determined by Impatience to Spend Income and Opportunity to Invest it. New York The MAcmillan Co., 1930, 13-14 PP. )