Truth - 真理 - Zhēnlǐ
The three planes of Truth.
Experience, the first,
Reason is next,
and the highest - knowing.
All other assertions
should be set aside.
~inspired by Deng Ming-Dao
(pics taken from http://bipblog.com/archives/3808294.html)
The first kind of truth is experience. Once you have experienced something, you know it. No one can persuade you to believe otherwise.
The second truth is reason. In certain cases, an answer may not be verified immediately, due to a limitation of subject or perspective. Atomic particles are too small to "see", and the movement of planets or galaxies is too large. Certain ideas may be so abstract we must use our imagination to bring them to life. Truths bestowed by reason are important, but it must be remembered that these facts come from analysis as opposed to physical experience.
The third way to truth is through spiritual knowledge. Entirely internal, the spiritual way is direct interaction with truth, through the higher faculties of the soul. Meditation provides perceptions of absolute certainty. Doubt dissolves, and there is no need for further investigation. This knowledge of self is beyond words, description, or rationalization. Be cognizant of the possibility of becoming disillusioned with the world, as the fruits of meditation may skew one's perspective of the active world. The danger lies in misunderstanding external truths for internal truths, thus ruining self-confidence. Avoid doubts and conflicting opinions by keeping your personal revelations private. What is known directly is yours alone.