In the second place, Feuerbach held quite correctly that scientific materialism is the foundation of the building of human knowledge but it is not the building itself. For we live not only in nature but in human society, and this has its theory of development and its science no less than nature. It was necessary, therefore, to bring the science of society, that is the so-called historical and philosophical sciences, into harmony with the materialistic foundations and to rebuild upon them. But this was not granted to Feuerbach. Here he stuck, in spite of the "foundations," held in the confining bonds of idealism, and to this he testified in the words "Backwards I am with the materialists, but not forwards." But Feuerbach himself did not go forward in his views of human society from his standpoint of 1840 and 1844, chiefly owing to that loneliness which compelled him to think everything out by himself, instead of in friendly and hostile conflict with other men of his calibre, although of all philosophers he was the fondest of intercourse with his fellows. We shall see later on how he thus remained an idealist. Here we can only call attention to the fact that Starcke sought the idealism of Feuerbach in the wrong place. "Feuerbach is an idealist; he believes in the advance of mankind" (p. 19). "The foundations, the underpinning of the whole, is therefore nothing less than idealism. Realism is for us nothing more than a protection against error while we follow our own idealistic tendencies. Are not compassion, love and enthusiasm for truth and justice ideal forces?" In the first place, idealism is here defined as nothing but the following of ideal aims. But these have necessarily to do principally with the idealism of Kant and his "Categorical Imperative." But Kant himself called his philosophy "transcendental idealism," by no means because he deals therein with moral ideals, but on quite other grounds, as Starcke will remember. The superstition that philosophical idealism pivots around a belief in moral, that is in social ideals, arose with the German non-philosophical Philistine, who commits to memory the few philosophical morsels which he finds in Schiller's poems. Nobody has criticised more severely the feeble Categorical Imperative of Kant--feeble because it demands the impossible and therefore never attains to any reality--nobody has ridiculed more cruelly the Philistine sentimentality imparted by Schiller, because of its unrealizable ideals, than just the idealist par excellence, Hegel. (See e. g. Phenomenology.)