Beginning with the seventeenth century, the old Theoretic Cabala is gradually superseded in Poland by the Practical Cabala,[110] taught by the new school of ARI[111] and Vital.[112] The Cabalist Isaiah Horowitz, author of the famous work on ascetic morals called SHeLoH,[113] had been trained in the yeshibahs of Cracow and Lemberg, and for several years (1600-1606) occupied the post of rabbi in Volhynia. His son, Sheftel Horowitz, who was rabbi in Posen (1641-1658), published the mystical work of his father, adding from his own pen a moralist treatise under the title _Vave ha-`Amudim_.[114] Nathan Spira, preacher and rector of the Talmudic academy in Cracow (1585-1633), made a specialty of the Practical Cabala. His more ingenious than thoughtful book, "Discovering Deep Things"[115] (_Megalle `Amukoth_, Cracow, 1637), contains an exposition in two hundred and fifty-two different ways of Moses' plea before God for permission to enter the Promised Land (Deuteronomy iii. 23). It consists of an endless chain of Cabalistic word-combinations and obscure symbolic allusions, yielding some inconceivable deductions, such as that Moses prayed to God concerning the appearance of the two Messiahs of the house of Joseph and David, or that Moses endeavored to eliminate the power of evil and to expiate in advance all the sins that would ever be committed by the Jewish people. Nathan Spira applied to the Cabala the method of the Rabbinical pilpul, and created a new variety of dialectic mysticism, which was just as far removed from sound theology as the scholastic speculations of the pilpulists were from scientific thinking. More wholesome and more closely related to life was the trend of the Jewish apologetic literature which sprang up in Poland in the last quarter of the sixteenth century. The religious unrest which had been engendered by the Reformation gave rise to several rationalistic sects with radical, anti-ecclesiastic tendencies. Nearest of all to the tenets of Judaism was the sect of the Anti-Trinitarians (called Unitarians, Arians, or Socinians[116]), who denied the dogma of the Trinity and the divine nature of Jesus, but recognized the religious and moral teachings of the Gospels. Among the Anti-Trinitarian leaders were the theologian Simon Budny, of Vilna, and Martin Chekhovich, of Lublin. Stung by the fact that the Catholic clergy applied to them the contemptuous appellation of "Judaizers," or semi-Jews, the sectarians were anxious to demonstrate to the world that their doctrine had nothing in common with Judaism. For this purpose they carried on oral disputes with the rabbis, and tried to expose the "Jewish falsehoods" in their works.