In ancient times, common sense operated in common with fantasy, the inductive with the speculative method. The discussion of their differences begins only with the understanding of the numerous disappointments caused by the still inexperienced judgment which have prevented an unobstructed view of the question up to modern times. But instead of attributing these disappointments to lack of understanding, they were charged to the account of the imperfection of the senses. The senses were called impostors and material phenomena untrue images. Who has not heard the lament about the unreliability of the senses? The misunderstanding of nature and of its phenomena led to a serious rupture with sense perceptions. The philosophers had deceived themselves and thought they had been deceived by the senses. In their anger they turned disdainfully away from the world of sensations. With the same uncritical faith with which the semblance had hitherto been accepted as truth, now uncritical doubt rejected the truth of sensations altogether. Research abandoned nature and experience, and began the work of speculative philosophy by "pure" thought. But no! Science did not permit itself to be entirely led astray from the path of common sense, from the way of truth of sense perceptions. Natural science soon stepped into the breach, and its brilliant successes gained for the inductive method the consciousness of its fertility, while on the other hand philosophy searched for a system by which all the great general truths might be opened up without specialized study, without sense perception and observation, by mere reason alone. Now we have a more than sufficient quantity of such speculative systems. If we measure them with the aforementioned standard of unanimousness, we find that philosophy agrees only on its disagreements. In consequence, the history of speculative philosophy, unlike the history of other sciences, consists less of a gradual accumulation of knowledge, than of a series of unsuccessful attempts to solve the general riddles of nature and life by "pure" thought, without the help of the objects and experience of the outer world. The most daring attempt in this line, the most artificial structure of thought, was completed by Hegel in the beginning of the nineteenth century. To use a common expression, he became as famous in the world of science as Napoleon I did in the world of politics. But Hegelian philosophy has not stood the test of time. Haym, in his work entitled "Hegel and His Time," says of Hegelian philosophy that "it was pushed aside by the progress of the world and by living history."