"If markets were sufficiently complete, with all futures periods and all uncertain contingencies already provided for in the contracts, the concept of property would cease to be problematic. All decisions would have been made in advance, and there would be no further questions of transfers to treat as just or unjust. Because in fact many of these markets do not exist, there are direct non-market relations which affect individuals' levels of satisfaction. Voluntary transfers become possible, but not all conceivable transfers can be made. Hence, voluntary transfers become biassed in direction, and the possible injustice of the whole system of transfers must be recognized."