THE 18th century professor from the University of Koenigsberg was so clock-like in going to his mid-morning lectures that people living in the houses he usually passed by would set their clocks upon seeing Prof. Dr. Immanuel Kant.

Once back home after a two- to three-hour lecture, Kant -- never married -- would sit down for a simple lunch prepared by his servant. Often, guests, friends and even students would sit down to share the meal with him. Such occasions generated academic, yet lively discussions. The afternoons were scheduled for serious study.

However, it was not “all study and no play,” for he was some kind of “party-popper.” He loved to attend banquets and parties. There he gathered information about events, places and persons. With pin-point questions he gained so much knowledge about the world.

But one day, Hume, a Scottish thinker claiming all we can know are the laws of the mind -- not the thing itself -- woke him up from his “dogmatic slumber.” Can Hume’s statement be true that our knowledge purely subjective? This question Kant raised by asking, “What can we really know?” For years, Kant worked on his first major book, Critique of Pure Reason.

His verdict: in trying to know the “thing-in-itself” we are aided by 1) a priori forms of space and time, and 2) categories of the mind. Furthermore, knowledge about God (exists?), soul (immortal?), and will (free?) should be accepted as postulates.

His first Critique, together with Religion Within the Bounds of Reason, endangered his servant’s faith; to prevent the danger of atheism Kant wrote two other Critiques: of Practical Reason, of Judgment, asking, “What can we believe or have faith in?” and “What can we hope for?”