Buddhism seldom positively asserts what is the Truth. [**] Rather, it teaches the truth-seekers to understand and to explore their own minds, for in the quest of Reality nothing is more important or befitting for the seeker than to know what the mind actually is rather than to know only what mind knows of--the so-called knowledge and objects known by the mind. Reality is the object known, but the first step is to understand the knower of this Reality. [***] Whatever one's beliefs, opinions, and thoughts, all these depend on the mind and come through the mind, for there is no possibility for one to escape from the sphere of mind in thinking or knowing.

After waking from sleep, each day of our lives begins with an awareness of 'I'. observed, "I think, therefore I am"--which seems logical to common sense since it feels the necessity for a knower in order for anything to be known. But whether or not this 'I' really exists and is substantial is debatable, says . Although Buddhism denies the reality of the ego, it does not absolutely deny the reality of the "awareness," or thinking-process (at least in Mahayana Buddhism). Therefore, it is of the utmost importance to know what this "awareness" or "mind" is.

Buddhist schools employ two different approaches in the study of mind. The Vaibhasika and Yogacara may be said to use the "horizontal" approach, i.e. studying the mind analytically by mapping its divisions, characteristics, functions, etc., including the 8 Consciousnesses and mental functions of the different stages of Samadhis. The Tantric [Buddhist] schools and Zen, [**] however, employ what may be called a "vertical" approach--urging the student to disregard the analysis of functions and peripheral knowledge of mind and instead to penetrate directly and deeply to the very foundation of mind-essence.

To clarify for the readers the Buddhist view of these two approaches in studying the mind, the translator will explain them through applying what may be called the "three-dimension system" to the mind: The first dimension--function; the second dimension--the form; the third dimension--the essence-of-mind.

The first dimension (Chinese "Yung"; Tibetan "Rtsl") means "activity" or "function"; the second dimension, (Chinese Shang; Tibetan Rnam Pa) refers to the "form" or "characteristics." The third dimension (Chinese Ti; Tibetan Ngo wo) points to the essence or real nature of mind. The manifestations in the first dimension of mind--the peripheral or outer realm of mind--are comparatively easy to comprehend. The second dimension, the form and characteristics, is not easily understood without a certain kind of study or investigation. The third dimension denotes the transcendental aspect of mind or the Dimension of Beyond.