In the case of material things, property value and capital value must be exactly equal. Property rights cover the ownership of a material thing. Material property consists of things viewed with reference to ownership; capital consists of the same things viewed with reference to their economic services. There are other property rights besides those in material things, various immaterial rights controlling the action of the individual and thus giving a sort of ownership of the individual's actions. Such are patents which forbid other men making a particular kind of machine; copyrights which forbid other men printing certain writings; legal contracts that limit the action of men in various ways, and thus appear to abridge their liberty. § II. THE ORIGIN OF PRIVATE PROPERTY [Sidenote: Property and income] 1. _Property is ownership, the legal control over the sources of economic income._ The Latin word property means ownership, and hence that which pertains to the individual, that which is a man's own. The control of property is greater or less. The law makes between property rights and equity rights certain subtle distinctions which have their reason in the history, if not in the logic, of the law, but which are not essential to economic discussion. What we are interested in are the equitable claims of men to wealth rather than the technical property rights. With that thought let us consider the value of the control of wealth. If a farm worth ten thousand dollars is mortgaged for five thousand dollars, its economic worth is ten thousand dollars after as before the mortgage, but the equitable claim is divided into two shares of five thousand dollars each. The value of the property right cannot, in a reasonable view, be greater than the value of the economic wealth it covers. There is much confusion in the law of taxation on this point. The law treats the farm as property and the debt upon it, whether secured by a mortgage or not, as another body of property. Needless to say, this leads to absurd conclusions in reasoning, and to gross injustice. [Sidenote: Forms and modes of ownership]