קל"ה - הלכות קריאת התורה ד:א
The first generations that existed in the world expressed kefirah (apostasy) by practicing their idol-worship (avodah zara). And, since the time that man's inclination for idol-worship was eliminated [during the time of Ezra HaSofer], the inclination to learn philosophy has strengthened itself. This is the kefirah of scientists. Through their backward wisdom they bring kefirah into the world. The truth is that idol-worship and philosophy are one.