While various views and methods have been called 'metaphysics' across history, this article approaches metaphysics first from the perspective of contemporary analytical philosophy, and then explores metaphysics in other traditions. In this vein, metaphysics seeks to answer two basic questions:
Topics of metaphysical investigation include 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 one another.
There are two broad conceptions about what "world" is studied by metaphysics. The strong, classical view assumes that the objects studied by metaphysics exist independently of any observer, so that the subject is the most fundamental of all sciences. The weaker, more modern view assumes that the objects studied by metaphysics exist inside the mind of an observer, so the subject becomes a form of introspection and conceptual analysis. Some philosophers, notably Kant, discuss both of these "worlds" and what can be inferred about each one.
Some philosophers and scientists, such as the logical positivists, reject the entire subject of metaphysics as meaningless, while others disagree and think that it is legitimate.
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.
Metaphysics continues asking "why" where science leaves off. For example, any theory of fundamental physics is based on some set of axioms, which may postulate the existence of entities such as atoms, particles, forces, charges, mass, and/or fields. Stating such postulates is considered to be the "end" of a science theory. Metaphysics takes these postulates and explores what they mean as human concepts. For example, do all theories of physics require the existence of space and time, objects, and properties? Or can they be expressed using only objects, or only properties? Do the objects have to retain their identity over time or do they change? If they change, then are they still the same object? Can theories be reformulated by converting properties or predicates (such as "red") into entities (such as redness or redness fields). Is the distinction between objects and properties fundamental to the physical world and/or to our perception of it?
Much recent work has been devoted to analyzing the role of metaphysics in scientific theorizing. Alexandre Koyré led this movement, declaring in his book Metaphysics and Measurement, "It is not by following experiment, but by outstripping experiment, that the scientific mind makes progress."Imre Lakatos maintained that all scientific theories have a metaphysical "hard core" essential for the generation of hypotheses and theoretical assumptions. Thus, according to Lakatos, "scientific changes are connected with vast cataclysmic metaphysical revolutions."
An example from biology of Lakatos' thesis: David Hull has argued that changes in the ontological status of the species concept have been central in the development of biological thought from Aristotle through Cuvier, Lamarck, and Darwin. Darwin's ignorance of metaphysics made it more difficult for him to respond to his critics because he could not readily grasp the ways in which their underlying metaphysical views differed from his own.
In physics, new metaphysical ideas have arisen in connection with quantum mechanics, where subatomic particles arguably do not have the same sort of individuality as the particulars with which philosophy has traditionally been concerned. Also, adherence to a deterministic metaphysics in the face of the challenge posed by the quantum-mechanical uncertainty principle led physicists such as Albert Einstein to propose alternative theories that retained determinism.A. N. Whitehead is famous for creating a process philosophy metaphysics inspired by electromagnetism and special relativity.
Katherine Hawley notes that the metaphysics even of a widely accepted scientific theory may be challenged if it can be argued that the metaphysical presuppositions of the theory make no contribution to its predictive success.
A number of individuals have suggested that much or all of metaphysics should be rejected. In the eighteenth century, David Hume took an extreme position, arguing that all genuine knowledge involves either mathematics or matters of fact and that metaphysics, which goes beyond these, is worthless. He concludes his Enquiry Concerning Human Understanding with the statement:
If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.
Thirty-three years after Hume's Enquiry appeared, Immanuel Kant published his Critique of Pure Reason. Although he followed Hume in rejecting much of previous metaphysics, he argued that there was still room for some synthetic a priori knowledge, concerned with matters of fact yet obtainable independent of experience. These included fundamental structures of space, time, and causality. He also argued for the freedom of the will and the existence of "things in themselves", the ultimate (but unknowable) objects of experience.
In the 1930s, A. J. Ayer and Rudolf Carnap endorsed Hume's position; Carnap quoted the passage above. They argued that metaphysical statements are neither true nor false but meaningless since, according to their verifiability theory of meaning, a statement is meaningful only if there can be empirical evidence for or against it. Thus, while Ayer rejected the monism of Spinoza, noted above, he avoided a commitment to pluralism, the contrary position, by holding both views to be without meaning. Carnap took a similar line with the controversy over the reality of the external world. This logical positivist school is now generally considered to have run its course, with AJ Ayer in particular saying "it was false" when asked what was wrong with it during a television interview.
Arguing against such rejections, the Scholastic philosopher Edward Feser has observed that Hume's critique of metaphysics, and specifically Hume's fork, is "notoriously self-refuting". Feser argues that Hume's fork itself is not a conceptual truth and is not empirically testable.
Some living philosophers, such as Amie Thomasson, have argued that many metaphysical questions can be dissolved just by looking at the way we use words; others, such as Ted Sider, have argued that metaphysical questions are substantive, and that we can make progress toward answering them by comparing theories according to a range of theoretical virtues inspired by the sciences, such as simplicity and explanatory power.
More on Indian philosophy: Hindu philosophy
S??khya is an ancient system of Indian philosophy based on a dualism involving the ultimate principles of consciousness and matter. It is described as the rationalist school of Indian philosophy. It is most related to the Yoga school of Hinduism, and its method was most influential on the development of Early Buddhism.
The S?mkhya is an enumerationist philosophy whose epistemology accepts three of six pramanas (proofs) as the only reliable means of gaining knowledge. These include pratyak?a (perception), anum??a (inference) and ?abda (?ptavacana, word/testimony of reliable sources).
Samkhya is strongly dualist. S?mkhya philosophy regards the universe as consisting of two realities; puru?a (consciousness) and prak?ti (matter). Jiva (a living being) is that state in which puru?a is bonded to prak?ti in some form. This fusion, state the Samkhya scholars, led to the emergence of buddhi ("spiritual awareness") and aha?k?ra (ego consciousness). The universe is described by this school as one created by purusa-prak?ti entities infused with various permutations and combinations of variously enumerated elements, senses, feelings, activity and mind. During the state of imbalance, one of more constituents overwhelm the others, creating a form of bondage, particularly of the mind. The end of this imbalance, bondage is called liberation, or moksha, by the Samkhya school.
The existence of God or supreme being is not directly asserted, nor considered relevant by the Samkhya philosophers. S??khya denies the final cause of Ishvara (God). While the Samkhya school considers the Vedas as a reliable source of knowledge, it is an atheistic philosophy according to Paul Deussen and other scholars. A key difference between Samkhya and Yoga schools, state scholars, is that Yoga school accepts a "personal, yet essentially inactive, deity" or "personal god".
Samkhya is known for its theory of gu?as (qualities, innate tendencies). Gu?a, it states, are of three types: sattva being good, compassionate, illuminating, positive, and constructive; rajas is one of activity, chaotic, passion, impulsive, potentially good or bad; and tamas being the quality of darkness, ignorance, destructive, lethargic, negative. Everything, all life forms and human beings, state Samkhya scholars, have these three gu?as, but in different proportions. The interplay of these gu?as defines the character of someone or something, of nature and determines the progress of life. The Samkhya theory of gu?as was widely discussed, developed and refined by various schools of Indian philosophies, including Buddhism. Samkhya's philosophical treatises also influenced the development of various theories of Hindu ethics.
Realization of the nature of Self-identity is the principal object of the Vedanta system of Indian metaphysics. In the Upanishads, self-consciousness is not the first-person indexical self-awareness or the self-awareness which is self-reference without identification, and also not the self-consciousness which as a kind of desire is satisfied by another self-consciousness. It is Self-realisation; the realisation of the Self consisting of consciousness that leads all else.
The word Self-consciousness in the Upanishads means the knowledge about the existence and nature of Brahman. It means the consciousness of our own real being, the primary reality. Self-consciousness means Self-knowledge, the knowledge of Prajna i.e. of Prana which is Brahman. According to the Upanishads the Atman or Paramatman is phenomenally unknowable; it is the object of realisation. The Atman is unknowable in its essential nature; it is unknowable in its essential nature because it is the eternal subject who knows about everything including itself. The Atman is the knower and also the known.
Metaphysicians regard the Self either to be distinct from the Absolute or entirely identical with the Absolute. They have given form to three schools of thought - a) the Dualistic school, b) the Quasi-dualistic school and c) the Monistic school, as the result of their varying mystical experiences. Prakrti and Atman, when treated as two separate and distinct aspects form the basis of the Dualism of the Shvetashvatara Upanishad. Quasi-dualism is reflected in the Vaishnavite-monotheism of Ramanuja and the absolute Monism, in the teachings of Adi Shankara.
Self-consciousness is the Fourth state of consciousness or Turiya, the first three being Vaisvanara, Taijasa and Prajna. These are the four states of individual consciousness.
There are three distinct stages leading to Self-realisation. The First stage is in mystically apprehending the glory of the Self within us as though we were distinct from it. The Second stage is in identifying the "I-within" with the Self, that we are in essential nature entirely identical with the pure Self. The Third stage is in realising that the Atman is Brahman, that there is no difference between the Self and the Absolute. The Fourth stage is in realising "I am the Absolute" - Aham Brahman Asmi. The Fifth stage is in realising that Brahman is the "All" that exists, as also that which does not exist.
In Buddhist philosophy there are various metaphysical traditions that have proposed different questions about the nature of reality based on the teachings of the Buddha in the early Buddhist texts. The Buddha of the early texts does not focus on metaphysical questions but on ethical and spiritual training and in some cases, he dismisses certain metaphysical questions as unhelpful and indeterminate Avyakta, which he recommends should be set aside. The development of systematic metaphysics arose after the Buddha's death with the rise of the Abhidharma traditions. The Buddhist Abhidharma schools developed their analysis of reality based on the concept of dharmas which are the ultimate physical and mental events that make up experience and their relations to each other. Noa Ronkin has called their approach "phenomenological".
Later philosophical traditions include the Madhyamika school of Nagarjuna, which further developed the theory of the emptiness (shunyata) of all phenomena or dharmas which rejects any kind of substance. This has been interpreted as a form of anti-foundationalism and anti-realism which sees reality has having no ultimate essence or ground. The Yogacara school meanwhile promoted a theory called "awareness only" (vijnapti-matra) which has been interpreted as a form of Idealism or Phenomenology and denies the split between awareness itself and the objects of awareness.
Immanuel Kant attempted a grand synthesis and revision of the trends already mentioned: scholastic philosophy, systematic metaphysics, and skeptical empiricism, not to forget the burgeoning science of his day. As did the systems builders, he had an overarching framework in which all questions were to be addressed. Like Hume, who famously woke him from his 'dogmatic slumbers', he was suspicious of metaphysical speculation, and also places much emphasis on the limitations of the human mind. Kant described his shift in metaphysics away from making claims about an objective noumenal world, towards exploring the subjective phenomenal world, as a Copernican Revolution, by analogy to (though opposite in direction to) Copernicus' shift from man (the subject) to the sun (an object) at the center of the universe.
Kant saw rationalist philosophers as aiming for a kind of metaphysical knowledge he defined as the synthetic apriori--that is knowledge that does not come from the senses (it is a priori) but is nonetheless about reality (synthetic). Inasmuch as it is about reality, it differs from abstract mathematical propositions (which he terms analytical apriori), and being apriori it is distinct from empirical, scientific knowledge (which he terms synthetic aposteriori). The only synthetic apriori knowledge we can have is of how our minds organise the data of the senses; that organising framework is space and time, which for Kant have no mind-independent existence, but nonetheless operate uniformly in all humans. Apriori knowledge of space and time is all that remains of metaphysics as traditionally conceived. There is a reality beyond sensory data or phenomena, which he calls the realm of noumena; however, we cannot know it as it is in itself, but only as it appears to us. He allows himself to speculate that the origins of phenomenal God, morality, and free will might exist in the noumenal realm, but these possibilities have to be set against its basic unknowability for humans. Although he saw himself as having disposed of metaphysics, in a sense, he has generally been regarded in retrospect as having a metaphysics of his own, and as beginning the modern analytical conception of the subject .
Nineteenth century philosophy was overwhelmingly influenced by Kant and his successors. Schopenhauer, Schelling, Fichte and Hegel all purveyed their own panoramic versions of German Idealism, Kant's own caution about metaphysical speculation, and refutation of idealism, having fallen by the wayside. The idealistic impulse continued into the early twentieth century with British idealists such as F. H. Bradley and J. M. E. McTaggart. Followers of Karl Marx took Hegel's dialectic view of history and re-fashioned it as materialism.
During the period when idealism was dominant in philosophy, science had been making great advances. The arrival of a new generation of scientifically minded philosophers led to a sharp decline in the popularity of idealism during the 1920s.
The early to mid twentieth century philosophy also saw a trend to reject metaphysical questions as meaningless. The driving force behind this tendency was the philosophy of logical positivism as espoused by the Vienna Circle.
At around the same time, the American pragmatists were steering a middle course between materialism and idealism. System-building metaphysics, with a fresh inspiration from science, was revived by A. N. Whitehead and Charles Hartshorne.
There are two fundamental aspects of everyday experience: change and persistence. Until recently, the Western philosophical tradition has arguably championed substance and persistence, with some notable exceptions, however. According to process thinkers, novelty, flux and accident do matter, and sometimes they constitute the ultimate reality.
In a broad sense, process metaphysics is as old as Western philosophy, with figures such as Heraclitus, Plotinus, Duns Scotus, Leibniz, David Hume, Georg Wilhelm Friedrich Hegel, Friedrich Wilhelm Joseph von Schelling, Gustav Theodor Fechner, Friedrich Adolf Trendelenburg, Charles Renouvier, Karl Marx, Ernst Mach, Friedrich Wilhelm Nietzsche, Émile Boutroux, Henri Bergson, Samuel Alexander and Nicolas Berdyaev. It seemingly remains an open question whether major "Continental" figures such as the late Martin Heidegger, Maurice Merleau-Ponty, Gilles Deleuze, Michel Foucault, or Jacques Derrida should be included.
In a strict sense, process metaphysics may be limited to the works of a few founding fathers: G. W. F. Hegel, Charles Sanders Peirce, William James, Henri Bergson, A. N. Whitehead, and John Dewey. From a European perspective, there was a very significant and early Whiteheadian influence on the works of outstanding scholars such as Émile Meyerson (1859-1933), Louis Couturat (1868-1914), Jean Wahl (1888-1974), Robin George Collingwood (1889-1943), Philippe Devaux (1902-1979), Hans Jonas (1903-1993), Dorothy M. Emmett (1904-2000), Maurice Merleau Ponty (1908-1961), Enzo Paci (1911-1976), Charlie Dunbar Broad (1887-1971), Wolfe Mays (1912-), Ilya Prigogine (1917-2003), Jules Vuillemin (1920-2001), Jean Ladrière (1921-), Gilles Deleuze (1925-1995), Wolfhart Pannenberg (1928-), and Reiner Wiehl (1929-2010).
While early analytic philosophy tended to reject metaphysical theorizing, under the influence of logical positivism, it was revived in the second half of the twentieth century. Philosophers such as David K. Lewis and David Armstrong developed elaborate theories on a range of topics such as universals, causation, possibility and necessity and abstract objects. However, the focus of analytical philosophy generally is away from the construction of all-encompassing systems and toward close analysis of individual ideas.
Among the developments that led to the revival of metaphysical theorizing were Quine's attack on the analytic-synthetic distinction, which was generally taken to undermine Carnap's distinction between existence questions internal to a framework and those external to it.
The philosophy of fiction, the problem of empty names, and the debate over existence's status as a property have all come of relative obscurity into the limelight, while perennial issues such as free will, possible worlds, and the philosophy of time have had new life breathed into them.
The analytic view is of metaphysics as studying phenomenal human concepts rather than making claims about the noumenal world, so its style often blurs into philosophy of language and introspective psychology. Compared to system-building, it can seem very dry, stylistically similar to computer programming or mathematics. Despite, or perhaps because of, this scientific dryness, it is generally regarded as having made "progress" where other schools have not. For example, concepts from analytical metaphysics are now routinely employed and cited as useful guides in computational ontologies for databases and to frame computer natural language processing and knowledge representation software.
The word "metaphysics" derives from the Greek words ???? (metá, "beyond", "upon" or "after") and ?????? (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- ("after") 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 ?? ???? ?? ?????? ?????? (tà metà tà physikà biblía) 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" (????? - phýsis 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, Expositio in librum Boethii De hebdomadibus, V, 1).
A person who does, or is doing, metaphysics is called a metaphysician.
There is a widespread use of the term in current popular literature which replicates this understanding, i.e. that the metaphysical equates to the non-physical: thus, "metaphysical healing" means healing by means of remedies that are not physical.