To-day we should call that a one-sided culture of the understanding, and add the warning, "Cultivate not only your understanding, but also, and especially, your heart." Socrates did the same. For, if the heart did not become free from its natural impulses, but remained filled with the most fortuitous contents and, as an uncriticised _avidity_, altogether in the power of things, _i. e._ nothing but a vessel of the most various _appetites_,--then it was unavoidable that the free understanding must serve the "bad heart" and was ready to justify everything that the wicked heart desired. Therefore Socrates says that it is not enough for one to use his understanding in all things, but it is a question of what _cause_ one exerts it for. We should now say, one must serve the "good cause." But serving the good cause is--being moral. Hence Socrates is the founder of ethics. Certainly the principle of the Sophistic doctrine must lead to the possibility that the blindest and most dependent slave of his desires might yet be an excellent sophist, and, with keen understanding, trim and expound everything in favor of his coarse heart. What could there be for which a "good reason" might not be found, or which might not be defended through thick and thin? Therefore Socrates says: "You must be 'pure-hearted' if your shrewdness is to be valued." At this point begins the second period of Greek liberation of the mind, the period of _purity of heart_. For the first was brought to a close by the Sophists in their proclaiming the omnipotence of the understanding. But the heart remained _worldly-minded_, remained a servant of the world, always affected by worldly wishes. This coarse heart was to be cultivated from now on--the era of _culture of the heart_. But how is the heart to be cultivated? What the understanding, this one side of the mind, has reached,--to wit, the capability of playing freely with and over every concern,--awaits the heart also; everything _worldly_ must come to grief before it, so that at last family, commonwealth, fatherland, and the like, are given up for the sake of the heart, _i. e._ of _blessedness_, the heart's blessedness. Daily experience confirms the truth that the understanding may have renounced a thing many years before the heart has ceased to beat for it. So the Sophistic understanding too had so far become master over the dominant, ancient powers that they now needed only to be driven out of the heart, in which they dwelt unmolested, to have at last no part at all left in man. This war is opened by Socrates, and not till the dying day of the old world does it end in peace.