Since the rise of the theoretical Kabbalah in Spain in the thirteenth century, which must be considered a reaction against the system of intellectualism as laid down by Maimonides, we can observe in Jewish history two spiritual tendencies striving for dominance: Irrationalism in all its forms and Intellectualism in all its aberrations. Ahad Ha'am represents the line of development, of Maimonides, the Gaon of Wilna, Krochmal. The parallel line to the theoretical Kabbalah is the practical Kabbalah which began in Palestine in the sixteenth century and Hassidism which originated in Poland in the eighteenth century. The intellectualists maintain that the prime essential of the soul is intellect and that Judaism is based not on metaphysical will but on intellectual cognition. For our mediaeval intellectualists and those of the eighteenth century, this premise resulted in the conception of a Judaism which lays more stress on knowledge (Torah) than on the practice of the religious ceremonies (Avodah). It is, of course, understood that the older representatives of Jewish Intellectualism were as God-fearing and observing as their mystical opponents. But basing Judaism on knowledge and cognition, they maintained that the first thing a Jew should do is to study and accept the advice of old: Thou shalt recognize the God of thy fathers. In opposition to these teachings is the conception of Judaism as represented by Kabbalists and Hassidim. These lay more stress on the practice of Judaism, claiming that Judaism is primarily a matter of will and not of knowledge. It is not a coincidence that while among Jewish intellectualists in the East (Mithnagdim) the knowledge of the Talmud and of Rabbinic Judaism is widely spread because they consider this the first duty of the Jew, there prevails among the Hassidim ignorance of the Talmud and of Rabbinic Judaism. Ahad Ha'am is today the representative of Intellectual Judaism as conceived by his time, as the Gaon of Wilna was in his day the representative of intellectual Judaism. It is very characteristic of this Jewish school of thought that a man like the Gaon of Wilna has written a system of geometry and was interested in mathematics and logic. With his logical mind he created a new method of studying the Talmud which is marked by simplicity and clearness. Ahad Ha'am achieved in the domain of Hebrew thought and literature what the Gaon of Wilna had achieved in Talmudic methodology. As the Gaon of Wilna did away with "Pilpul" sophistry, so Ahad Ha'am did away with the confusing and unproductive "Hakira," unsystematic discussion of abstract thought, and introduced economy of thought and of expression--a clear terminology and a systematic formulation of principles and ideas. That is what has given him the leading position in modern Hebrew literature.