The Sages of the Talmud said: "For anyone that looks at three things, it is better that they were not created: (1) What is above, (2) What is below (3) What is inside." This goes along with the idea of Kant that when one tries to use reason in areas of unconditioned reality contradictions are created. The practical lesson from this is not to think about spiritual things because that creates contradictions in one's soul.