It would be vain to seek the correction of Hegel among those thinkers that were his contemporaries, for they were all, though in various degrees, inferior to him. None of them had attained, through Kant, to the height attained by Hegel. Dwelling on a lower level, they could certainly refuse to recognize him and vituperate him, but they could never collaborate with and beyond him, in the progress of truth. Herbart held those concepts to which the particular sciences give rise to be contradictory, but he claimed to surpass the contradiction by means of an elaboration of the concepts (_Bearbeitung der Begriffe_), conducted in the very method of the old Logic, that is, of the Logic of the empirical sciences. Schleiermacher renounced the attempt to reach the unity of the speculative and the empirical, of Ethic and Physics, that is, the realization of the pure idea of knowledge; and he substituted for that ideal, which for him was unattainable, _criticism,_ a form of worldly wisdom; that is to say, of philosophy (_Weltweisheit_) which gave access to theology and to religious feeling.[19] Schopenhauer accepted the distinction between concept and idea, the first abstract and artificial, the second concrete and real; but so slight was his understanding of the idea (which he called the Platonic idea) that he confused it with the concept of natural species,[20] that is to say, precisely with one of the most artificial and arbitrary of empirical concepts. Finally, Schelling, who had been a precursor of Hegel in his youth and had collaborated with him, not only failed to improve his logic of the intuition in his second philosophical period, but he abandoned even this embryonic form of the concrete concept, and gave himself over as a prey to the will and to irrationality. In his positive philosophy the old adversary of Jacobi made a bad combination of the alogism of Jacobi with the Hegelian idea of development and with mythologism, as in metaphysic he had anticipated the blind will of Schopenhauer.[21] [Sidenote: _Later positivism and psychologism._]