MATERIAL PHENOMENA
The Abhidhamma classifies material phenomena into primary and secondary elements. Primary elements are called the four great essentials (mahàbhåtà), comprising earth, water, fire and air—each denoting respectively particular material qualities, viz. softness/hardness, fluidity/cohesion, coolness/heat, and motion/pressure. Secondary elements are derived from, or dependent upon, the four great essentials, e.g. colour, sound, smell, taste, gender, nutriment and the sensitive substances in the sense-organs that register light, colour, sound, smell, taste, and physical sensation. The four great essentials are the fundamental constituents of matter and are inseparable from each other. Through various combinations with other derived elements, they form minute, elementary particles called kalàpas, of which all animate and inanimate material phenomena are ultimately composed. In fact, the four great essentials and four derivatives colour, smell, taste and nutriment—are always bound together and are present in all material objects, from the simplest to the most complex. The most fundamental kalapa consists solely of these eight elements while the most complex one comprises a total of eighteen elements. Each kalapa has a lifespan of seventeen mind-moments.
