Karl Marx belongs to the ranks of those philosophical and sociological thinkers who throw potent thought-ferment into the world, and set in motion the masses of mankind. They awaken slumbering doubts and contradictions. They proclaim new modes of thought, new social forms. Their systems may sooner or later become obsolete, and the ruthless march of time may finally overthrow their intellectual edifice; meanwhile, however, they stimulate into activity the minds of countless men, inflame countless human hearts, imprinting on them characteristics which are transmitted to coming generations. This is the grandest and finest work to which any human being can be called. Because these thinkers have lived and worked, their contemporaries and successors think more clearly, feel more intensely, and are richer in knowledge and self-consciousness.
The history of philosophy and of social science is comprised in such systems and generalisations. They are the index to the annals of mankind. None of these systems is complete, none comprehends all human motives and capacities, none exhausts all the forces and currents of human society. They all express only fragmentary truths, which, however, become effective and achieve success because they are shining lights amidst the intellectual confusion of the generation which gives them birth, bringing it to a consciousness [x]of the questions of the time, rendering its further development less difficult, and enabling its strongest spirits to stand erect, with fixity of purpose, in critical periods.
Hegel expresses himself in a similar sense where he remarks: "When the refutation of a philosophy is spoken of, this is usually meant in an abstract negative (completely destructive) sense, so that the confuted philosophy has no longer any validity whatever, and is set aside and done with. If this be so, the study of the history of philosophy must be regarded as a thoroughly depressing business, seeing that this study teaches that every system of philosophy which has arisen in the course of time has found its refutation. But if it is as good as granted that every philosophy has been refuted, yet at the same time it must be also asserted that no philosophy has been refuted, nor ever can be refuted ... for every philosophical system is to be considered as the presentation of a particular moment or a particular stage in the evolutionary process of the idea.