It was only by adopting a preposterous theory of value that Ricardo was able to maintain that the laborer, selling himself for wages to the proprietor, would always command his cost of production, _i.e._, his daily subsistence. Even that slender consolation vanished later on before the renewed investigation of value made by Jevons,[77] who demonstrated that the value of a commodity is a function of the quantity available, and may fall to zero when the supply outruns the demand so far as to make the final increment of the supply useless.[78] A fact which the unemployed had discovered, without the aid of the differential calculus, before Jevons was born. Private property, in fact, left no room for new comers. Malthus pointed this out, and urged that there should be no newcomers, that the population should remain stationary. But the population took exactly as much notice of this modest demand for stagnation, as the incoming tide took of King Canute’s ankles. Indeed the demand was the less reasonable since the power of production per head was increasing faster than the population (as it still is), the increase of poverty being produced simply by the increase and private appropriation of rent. After Ricardo had completed the individualist synthesis of production and exchange, a dialectical war broke out. Proudhon had only to skim through a Ricardian treatise to understand just enough of it to be able to shew that political economy was a _reductio ad absurdum_ of private property instead of a justification of it. Ferdinand Lassalle, with Ricardo in one hand and Hegel in the other, turned all the heavy guns of the philosophers and economists on private property with such effect, that no one dared to challenge his characteristic boasts of the irresistible equipment of Social Democracy in point of culture. Karl Marx, without even giving up the Ricardian value theory, seized on the blue books which contained the true history of the leaps and bounds of England’s prosperity, and convicted private property of wholesale spoliation, murder and compulsory prostitution; of plague, pestilence, and famine; battle, murder, and sudden death. This was hardly what had been expected from an institution so highly spoken of. Many critics said that the attack was not fair: no one ventured to pretend that the charges were not true. The facts were not only admitted; they had been legislated upon. Social Democracy was working itself out practically as well as academically. Before I recite the steps of the transition, I will, as a matter of form, explain what Social Democracy is, though doubtless nearly all my hearers are already conversant with it.