Cognition covers the arts of problem solving. The Chaos field of study covers any activity that studies Chaos in order to manifest the material. Śūnyatā, शून्यता (Sanskrit noun from the adj. sūnya - 'void' ), Suññatā (Pāli; adj. suñña), stong pa nyid (Tibetan), Kuu, 空 (Japanese) qoɣusun (Mongolian) meaning "Emptiness" or "Voidness", is a characteristic of empirical phenomena arising from the fact (as observed and taught by the Buddha) that the impermanent nature of form means that nothing possesses essential, enduring identity (see anattā). In the Buddha's spiritual teaching, insight into the emptiness of phenomena (Pali: suññatānupassanā) is an aspect of the cultivation of insight (vipassanā-bhāvanā) that leads to wisdom and inner peace. The importance of this insight is especially emphasised in Mahayana Buddhism. Widely misconceived as a doctrine of nihilism, the teaching on the emptiness of persons and phenomena is unique to Buddhism, constituting an important metaphysical critique of theism with profound implications for epistemology and phenomenology.

Śūnyatā signifies that everything one encounters in life is empty of absolute identity, permanence, or an in-dwelling 'self'. This is because everything is inter-related and mutually dependent - never wholly self-sufficient or independent. All things are in a state of constant flux where energy and information are forever flowing throughout the natural world giving rise to and themselves undergoing major transformations with the passage of time. This teaching never connotes nihilism - nihilism is, in fact, a belief or point of view that the Buddha explicitly taught was incorrect - a delusion, just as the view of materialism is a delusion (see below). In the English language the word emptiness suggests the absence of spiritual meaning or a personal feeling of alienation, but in Buddhism the realization of the emptiness of phenomena enables liberation from the limitations of form in the cycle of uncontrolled rebirth.

The theme of śūnyatā emerged from the Buddhist doctrines of Anatta (Pali, Sanskrit:Anātman—the nonexistence of the self, or Ātman) and Paticcasamuppada (Pali, Sanskrit: pratītyasamūtpāda, Interdependent Arising). The Suñña Sutta, part of the Pali Canon, relates that the monk Ananda, the attendant to Gautama Buddha asked:

"It is said that the world is empty, the world is empty, lord. In what respect is it said that the world is empty?"
"Insofar as it is empty of a self or of anything pertaining to a self: Thus it is said, Ananda, that the world is empty." - Buddha

Over time, many different philosophical schools or tenet-systems (siddhānta in Sanskrit) have developed within Buddhism in an effort to explain the exact philosophical meaning of emptiness.

After the Buddha, Śūnyatā was further developed by Nāgārjuna and the Madhyamaka school, which is usually counted as an early Mahayana school. Śūnyatā ("positively" interpreted - see Tathagatagarbha section below) is also an important element of the Tathagatagarbha literature, which played a formative role in the evolution of subsequent Mahayana doctrine and practice. In the Tibetan Buddhist tradition, detailed dialogs between the perspectives of the various schools are preserved in order to train students. For example, in the Tibetan tradition some of the main philosophical schools are listed as: Vaibhasika, Sautrantika, Cittamatra, and several schools within Madhyamaka (such as Svatantrika-Madhyamika and Prasangika-Madhyamika).

It should be noted that the exact definition and extent of shunyata varies within the different Buddhist schools of philosophy which can easily lead to confusion. These tenet-systems all explain in slightly different ways what phenomena 'are empty of', which phenomena exactly are 'empty' and what emptiness means. For example, in the Cittamatra school it is said that the mind itself ultimately exists, but other schools like the Madhyamaka deny this. In the Mahayana Tathagatagarbha sutras, in contrast, only impermanent, changeful things and states (the realm of samsara) are said to be empty in a negative sense - but not the Buddha or Nirvana, which are stated to be real, eternal and filled with inconceivable, enduring virtues. Further, the Lotus Sutra states that seeing all phenomena as empty (sunya) is not the highest, final attainment: the bliss of total Buddha-Wisdom supersedes even the vision of complete emptiness.