The Four Imponderables: The Buddha warned that one might become unhinged and mentally imbalanced by pondering any of these four unfathomable things:
- The range of a Buddha (the extent of the influence of a Buddha from the development of the Ten Perfections).
- The range of one absorbed in jhana (the power one might obtain from the meditative absorptions)
- The incomprehensibly complex working out of the consequences of karma (volitional actions)
- A first moment, initial cause, or purpose for the universe
The importance of the meditative absorptions (jhanas) can therefore hardly be overstated. In Sanskrit, the word "absorption" is dhyana, in Pali, jhana. Throughout the Pali Canon, the Buddha defines Right Concentration (samma samadhi) as entering the first Four Jhanas.
Jhana did not develop in a Buddhist context but was prevalent in the Indian subcontinent before the Buddha in various yogic systems of spiritual training. In Jainism, an ancient religion of extreme asceticism and ahimsa (non-harming) that developed alongside Buddhism and survives today in India, it is called Samayika. This is in the Prakrit dialect, somewhat akin to the Pali word Shamatha (Serenity), referring to the practice of developing the absorptions.
He became a buddha by realizing that rather than asceticism and self-mortification, jhana was the path. The Five Mental Hindrances were the problem, and they absent in jhana. As he gained meditative stability, he developed the factor of mindfulness. This combination gave rise to insight, enlightenment, and liberation overnight.
Unless one is liberated (nirvana), the positive karmic result of mastering the jhanas is rebirth in successively more exalted celestial planes. (See WQ article on the 31 Planes of Existence for detailed explanation). The negative karmic result of unprofitably wielding such power is hard to fathom because rebirth into heaven does not preclude future rebirth elsewhere.