What Hegel says here about philosophy is true also of systems of social science, and styles and forms in art. The displacement of one system by another reflects the historical sequence of the various stages of social evolution. The characteristic which is common to all these systems is their vitality. In spite of their defects and difficulties there surges through them a living spirit from the influence of which contemporaries cannot escape. Opponents may put themselves to endless trouble to contradict such systems, and show up their shortcomings and inconsistencies, and yet, with all their pains, they do not succeed in attaining their object; their logical sapping and mining, their passionate attacks break against the vital spirit which the creative genius has breathed into his work. The deep impression made on us by this vitality is one of the main factors in the formation of our judgments upon scientific and artistic achievements. Mere formal perfection and beauty through which the life of the times does not throb can never create this impression. Walter Scott, who was often reproached with defects and inconsistencies in the construction of his novels, once made answer with the following anecdote: A French sculptor, who had taken up his abode in Rome, was fond of taking to the Capitol his artistically inclined countrymen who were travelling in Italy, to show them the equestrian statue of Marcus Aurelius, on which occasions he was at pains to demonstrate that the horse was defectively modelled, and did not meet the requirements of anatomy. After one of these criticisms a visitor urged him to prove his case in a concrete form by constructing a horse on correct artistic principles. The critic set to work, and when, after the lapse of a year, his friends were again visiting Rome, exhibited to them his horse. It was anatomically perfect. Proudly he had it brought to the Capitol, in order to compare both productions and so celebrate his triumph. Quite absorbed in his critical comparison, the French sculptor after a while gave way to a burst of genuine artistic feeling, which caused him pathetically to exclaim, "_Et pourtant cette bete-la est vivante, et la mienne est morte!_" (And yet that animal is alive, while mine is dead.) Quite a number of Marxian critics find themselves in the same position as the hypercritical French sculptor. Their formal and logically complete economic doctrines and systems of historical philosophy, provided with pedantically correct details and definitions, remain dead and ineffective. They do not put us into contact with the relations of the time, whereas Marx has bequeathed both to the educated and the uneducated, to his readers and to non-readers, a multitude of ideas and expressions relating to social science, which have become current throughout the whole world.