654 PONTIFICIAE ACADEMIAE SCTENTIARVM SCRIPTA VARIA - 2¢ of goods and leisure which, in terms of time required, add up to a fixed amount determined by the existing working population and technical knowledge. To express the same thing in another way, we might say that the choice between products and leisure is not merely a possibility, but a necessity, if full employment is to be maintained. (There does not exist the alternative of not choosing). Technical progress, which cha- racterises our societies and which brings with it that choice, does not come — so to speak — under the form of a gift which, by being always susceptible of being refused, only could add to, and never diminish, the pre-existing wealth. It comes under the form of a flow, which cannot be stopped and has to be continually channelled in new directions, which themselves have to be discovered anew because the old ones saturate. This entails an ever-standing problem of utilization, under a fixed restriction represented by condition (V.12); a problem for which the failure to find solutions may cause damage to the previous situation. Before closing our comments on condition (V.12), we may add that there is a third way of keeping equilibrium over time. This would be io regard — as indeed we have done — the variations of the r/s as determined by the evolution of con- sumers’ preferences, but to have among them at least some #,’s which are not dependent on such preferences and which are flexible enough and capable of being influenced in such a way as to keep condition (V.12) satisfied. This is not a fanciful remark; it is in fact an important one, on practical grounds. It means that, if there is an external Agent or institutional Organization that is interested in keeping full employment, it is possible for this Agent or Organization — when any other mechanism which might have been put into operation fails — to act and to attain the aim of full employment simply by inflating total demand. 10] Pasinetti - pag. 84