  Within the history of occidental philosophy and science, Bacon identifies only three revolutions or periods of learning: the heyday of the Greeks and that of the Romans and Western Europe in his own time (Bacon IV [1901], 70ff.). This meager result stimulated his ambition to establish a new system of the sciences. This tendency can already be seen in his early manuscripts, but is also apparent in his first major book, The Advancement of Learning. In this work Bacon presents a systematic survey of the extant realms of knowledge, combined with meticulous descriptions of deficiencies, leading to his new classification of knowledge. In The Advancement (Bacon III [1887], 282f.) a new function is given to philosophia prima, the necessity of which he had indicated in the Novum Organum, I, Aphorisms LXXIX–LXXX (Bacon IV [1901], 78–9). In both texts this function is attributed to philosophia naturalis, the basis for his concept of the unity of the sciences and thus of materialism.