The ensuing period, both in Germany and in the whole of Europe, had little philosophical interest. It was marked by the reappearance of a form of naturalism and of Empiricism, in part justified by the abuse of the dialectic, which had sometimes, in the hands of Hegel's disciples, seemed altogether mad. But this recrudescence was in every way very poor in thought and inadequate to previous history. With this Empiricism is associated the deplorable _Logic_ of John Stuart Mill, one of those books which do least honour to the human spirit. That less than mediocre reasoner did not even succeed in producing a Logic of the natural sciences. He became involved in contradictions and tautologies, talking, for instance, of experience, which criticises itself and imposes its own limits upon itself, and of the principle of causality, as a law which affirms the existence of a law that there shall be a law. Still less had he any notion of what it is to philosophize, maintaining that in order to make progress in the moral and philosophical sciences it is necessary to apply to them the method of the physical sciences. Nothing is more puerile than his nominalism, which gives language a logical character, and then pretends that language must be logically reformed. Logical science was altogether lost in the evolutionism or physiologism of Spencer, and in the psychologism which had and still has many followers in Germany, in France, and in England, not less than in Italy. The state in which the Logic of philosophy is found in such an environment can be inferred from the fact that even mathematical Logic fared ill there, since there have not been wanting those who have dared to conceive a _psychology of arithmetic._ Finally, as a healthy corrective of psychologism, the danger of which to the old Logic had already been noted by Kant,[22] there came the revival of the Aristotelian, and even of the scholastic Logic, in which there yet lived, though in erroneous forms, the idea of the universal which had been discovered by the Greek philosophers. [Sidenote: _Eclectics. Lotze._]