ABSTRACT
The indicators for the fifth and fourth centuries B.C. show a considerable change in the spectrum of the epistemological mentality which is now the spectrum of the Idealistic theory of truth. If rationalism, the most powerful of all the currents of the period, is considered separately, it can be seen that it preserves all the earmarks of the Idealistic system of truth. The Idealistic culture, with the Idealistic forms of its main aspects, comes usually when the sensate culture begins to rise and the Ideational culture begins to decline. Degree of knowledge is based partly upon the data of the organs of senses and partly upon the logical laws of human intelligence which uses and fashions the raw material of the organs of senses according to its own laws. The development of the natural sciences, like the empirical system of truth, is subject to fluctuations, at times manifesting rapid advance, at others stagnating.
