Metaphysics is a traditional branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:
What is there?
What is it like?
A person who studies metaphysics is called a metaphysicist or a metaphysician. The metaphysician attempts to clarify the fundamental notions by which people understand the world, e.g., existence, objects and their properties, space and time, cause and effect, and possibility. A central branch of metaphysics is ontology, the investigation into the basic categories of being and how they relate to each other. Another central branch of metaphysics is cosmology, the study of the origin (if it had one), fundamental structure, nature, and dynamics of the universe.
Prior to the modern history of science, scientific questions were addressed as a part of metaphysics known as natural philosophy. Originally, the term "science" (Latin scientia) simply meant "knowledge". The scientific method, however, transformed natural philosophy into an empirical activity deriving from experiment unlike the rest of philosophy. By the end of the 18th century, it had begun to be called "science" to distinguish it from philosophy. Thereafter, metaphysics denoted philosophical enquiry of a non-empirical character into the nature of existence. Some philosophers of science, such as the neo-positivists, say that natural science rejects the study of metaphysics, while other philosophers of science strongly disagree.
The word "metaphysics " derives from the Greek words μετά (metá) ("beyond", "upon" or "after") and φυσικά (physiká) ("physics"). It was first used as the title for several of Aristotle's works, because they were usually anthologized after the works on physics in complete editions. The prefix meta- ("beyond") indicates that these works come "after" the chapters on physics. However, Aristotle himself did not call the subject of these books "Metaphysics ": he referred to it as "first philosophy ." The editor of Aristotle's works, Andronicus of Rhodes, is thought to have placed the books on first philosophy right after another work, Physics, and called them τὰ μετὰ τὰ φυσικὰ βιβλία (ta meta ta physika biblia) or "the books that come after the (books on] physics". This was misread by Latin scholiasts, who thought it meant "the science of what is beyond the physical ". However, once the name was given, the commentators sought to find intrinsic reasons for its appropriateness. For instance, it was understood to mean "the science of the world beyond nature" (phusis in Greek ), that is, the science of the immaterial. Again, it was understood to refer to the chronological or pedagogical order among our philosophical studies, so that the "metaphysical sciences" would mean "those that we study after having mastered the sciences that deal with the physical world " (St. Thomas Aquinas, "In Lib, Boeth. de Trin.", V, 1).
There is a widespread use of the term in current popular literature which replicates this error, i.e. that metaphysical means spiritual non-physical : thus, "metaphysical healing " means healing by means of remedies that are not physical .
Given the emphasis in Buddhist teachings on the role of erroneous belief as a cause of unhappiness, it was natural that Buddhist philosophers should focus on questions of ontology and the theory of causation. Ontology was important, since a kind of intellectual error that was supposed to lead to unhappiness was being mistaken about what exists. The theory of causation was important, since the eradication of the cause of unhappiness was supposed to result in the removal of unhappiness itself.
The earliest attempts to systematize the teachings of Buddhism were in the genre of literature known as ‘Abhidharma’, in which all the factors of human experience were classified according to a variety of schemata (see Buddhism, Ābhidharmika schools of). The study of the relationships among these classes of factors eventually evolved into a detailed theory of causality, in which several types of causal relationship were enumerated. There were many schools of Abhidharma, and each had its own set of schemata for the classification and enumeration of the factors of experience. Indeed, each had its own interpretation of what the very word ‘Abhidharma’ means; among the possible interpretations of the word, a common one is that it means a higher or more advanced doctrine, or a doctrine that leads to a higher form of wisdom. The variety of approaches taken in Abhidharma literature makes it difficult to discuss this literature in any but the most general way. Among most schools of Abhidharma, there was a commitment to the idea that the best strategy for coming to an understanding of any complex being is to analyse that being into its ultimate parts. An ultimate part is that which cannot be analysed into anything more simple. Most Buddhist systematists held to the principle that the ultimately simple building blocks out of which things are made are ultimately real, while complex things that are made up of more simple parts are not ultimately real; they are held to be real only through the consensus of a community. As was seen above in the section on human nature (§1), for example, there was a strong tendency for Buddhists to accept that a person’s character is the product of many components; these components were held to be real, but the person was held to be ultimately unreal. The idea of a person may be a fiction, but it is one that makes the running of society more manageable, and therefore it can be regarded as a consensual reality, in contrast to an ultimate reality.
The philosopher Nāgārjuna questioned the whole attempt to make a distinction between consensual and ultimate truths. One interpretation of his philosophical writings is that he was trying to show that every attempt to understand the world can only be an approximation on which there may be some degree of consensus; there is, however, no understanding that can claim to have arrived at an adequate description of things as they really are. Along with this radical criticism of the very enterprise of trying to discern ultimate from consensual realities, Nāgārjuna criticized the doctrine that the simple constituents that serve as causes of more complex beings are more real than the complex beings themselves. This principle had rested on the assumption that the more simple a being is, the closer it is to being independent. In fact, he argued, the apparently simple constituents are no less dependent than their apparently complex effects. To this fact of being dependent upon other things, Nāgārjuna gave the name emptiness; since all beings are dependent for their existence on other beings, he said, all beings are empty.
Later Buddhist philosophers, beginning especially with Dharmakīrti, devoted their energy increasingly to refuting the claims, advanced by some Brahmanical thinkers, that the whole universe can be traced back to a single cause. Dharmakīrti argued that if all things in the history of the world had a single cause, such as God or some type of primordial matter, then there would be no way to account for all the formal variety in the world at any given time, nor would it be possible to account for the fact that events unfold in sequences. If all the formal and temporal diversity are already inherent in the cause, he argued, then the cause is not a single thing after all. One might argue that the diversity exists in the single cause only as a potential of some kind; this, however, only raises the problem of explaining how that potential is actualized. If the potential is activated by something outside the cause that possesses it, then the outside agency must be counted among the causal factors along with the primary cause, in which case there is no longer a single cause. Besides general arguments directed against the view that all things could have any single cause, Dharmakīrti also gave arguments against the existence of a creator God in particular. The universe, he observed, shows no signs of having been designed by anyone intelligent. Even if it were conceded for the sake of argument that the world might have been made by some intelligent being, there is still no sign that this being had any concern for any living beings. Later generations of Buddhist philosophers expanded upon Dharmakīrti’s arguments against the existence of a single intelligent creator, but most of these expansions took the form of replying to the objections of opponents rather than formulating new arguments (see Causation, Indian theories of §6).
During the last five hundred years that Buddhism was an important factor in Indian philosophy (600–1100), criticism of Buddhist doctrines by Brahmanical and Jaina religious philosophers, as well as from anti-religious materialists, forced Buddhist thinkers to refine some of their arguments and even to abandon some of their doctrinal positions. Arguments among Buddhists became much less a feature of Buddhist philosophy than arguments against non-Buddhist opponents. Within Buddhism itself, there was a tendency to try to reconcile differences that in earlier centuries had divided Buddhists against each other, at least doctrinally. This new spirit of overcoming sectarianism resulted in several ingenious attempts to fuse the old Abhidharma schools, the Mādhyamika schools, the Yogācāra schools and the Buddhist epistemologists. Few new issues were raised in this last five-hundred-year period, and not many new arguments were discovered to defend old positions. Careful scholarship tended to replace philosophical innovation as the principal preoccupation of later Buddhist intellectuals, such as Śāntarakṣita, Kamalaśīla, Jñānaśrīmitra and Ratnakīrti. It was during this period of the decline of Buddhism in India that Buddhist philosophy was introduced into Tibet. Once established there, it received a new impetus from a range of Tibetan intellectuals who were able to study many of these doctrines with a fresh perspective.