Three major artificialities have been drafted and grafted by law upon all modern production; hangovers from petty customs originating in feudal circumstances. Many of these traditions have been blown up into supposed economic patterns: but all forms of rent and all illegitimate. Rent for money; rent for land; really only extrinsic forms of unearned increment; and the third artificiality is traffic in invention. A graft by way of patents is another but less obvious form of rent.
From F L Wright, The Living City. Original copyright 1958. March, 1970 New American Library edition.