Everything, every-thing, or every thing is all that exists; the opposite of nothing, or its complement. It is the totality of things relevant to some

subject matter Subject matter, in general, is anything which can be content for some theory. Subject matter may refer to: * Patentable subject matter (or statutory subject matter), defining whether patent protection is available * Subject-matter jurisdiction, d ...

. Without expressed or implied limits, it may refer to anything. The universe is everything that exists theoretically, though a

multiverse The multiverse is a hypothetical group of multiple universes. Together, these universes comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The di ...

may exist according to theoretical cosmology predictions. It may refer to an anthropocentric worldview, or the sum of human experience, history, and the human condition in general."This is the excellent foppery of the world..." — Shakespeare, '' King Lear'', Every object and entity is a part of everything, including all physical bodies and in some cases all

abstract object In metaphysics, the distinction between abstract and concrete refers to a divide between two types of entities. Many philosophers hold that this difference has fundamental metaphysical significance. Examples of concrete objects include plants, hum ...

Scope

In ordinary conversation, ''everything'' usually refers only to the totality of things relevant to the subject matter. When there is no expressed limitation, ''everything'' may refer to the universe, or the world. The universe is most commonly defined as everything that physically exists: the entirety of time, all forms of matter, energy and

momentum In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...

, and the physical laws and

constants Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific const ...

that govern them. However, the term "universe" may be used in slightly different contextual senses, denoting such concepts as the '' cosmos'', the '' world'', or '' nature''. According to some speculations, this universe may be one of many disconnected universes, which are collectively denoted as the

. In the

bubble universe theory Eternal inflation is a hypothetical inflationary universe model, which is itself an outgrowth or extension of the Big Bang theory. According to eternal inflation, the inflationary phase of the universe's expansion lasts forever throughout most of ...

, there is an infinite variety of universes, each with different

physical constant A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time. It is contrasted with a mathematical constant, ...

s. In the

many-worlds hypothesis The many-worlds interpretation (MWI) is an interpretation of quantum mechanics that asserts that the universal wavefunction is objectively real, and that there is no wave function collapse. This implies that all possible outcomes of quantum ...

, new universes are spawned with every quantum measurement. By definition, these speculations cannot currently be tested experimentally, yet, if multiple universes do exist, they would still be part of everything. Especially in a metaphysical context, ''World'' may refer to everything that constitutes reality and the universe: see World (philosophy). However, world may only refer to '' Earth'' envisioned from an anthropocentric or human worldview, as a place by human beings.

In theoretical physics

In theoretical physics, a ''theory of everything'' (TOE) is a hypothetical theory that fully explains and links together all known physical phenomena. Initially, the term was used with an ironic connotation to refer to various overgeneralized theories. For example, a great-grandfather of Ijon Tichy—a character from a cycle of Stanisław Lem's science fiction stories of the 1960s—was known to work on the "General Theory of Everything". Over time, the term stuck in popularizations of

quantum physics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...

to describe a theory that would unify or explain through a single model the theories of all fundamental interactions of nature. There have been many theories of everything proposed by theoretical physicists over the last century, but none have been confirmed experimentally. The primary problem in producing a TOE is that the accepted theories of quantum mechanics, general relativity, or special relativity are hard to combine. Theories exploring quantum mechanics and string theory are easier to combine. Based on theoretical holographic principle arguments from the 1990s, many physicists believe that 11-dimensional M-theory, which is described in many sectors by matrix string theory, and in many other sectors by perturbative string theory, is the complete theory of everything. Other physicists disagree.

In philosophy

In philosophy, a ''theory of everything'' or ''TOE'' is an ultimate, all-encompassing explanation of nature or reality.Rescher, Nicholas (2006a). "Holistic Explanation and the Idea of a Grand Unified Theory". Collected Papers IX: Studies in Metaphilosophy.Rescher, Nicholas (2006b). "The Price of an Ultimate Theory". Collected Papers IX: Studies in Metaphilosophy.Walker, Mark Alan (March 2002)
"Prolegomena to Any Future Philosophy"
Journal of Evolution and Technology Vol. 10. Adopting the term from physics, where the search for a theory of everything is ongoing, philosophers have discussed the viability of the concept and analyzed its properties and implications. Among the questions to be addressed by a

philosophical theory A philosophical theory or philosophical position''Dictionary of Theories'', Jennifer Bothamley is a view that attempts to explain or account for a particular problem in philosophy. The use of the term "theory" is a statement of colloquial English ...

of everything are: "Why is reality understandable?", "Why are the laws of nature as they are?", and " Why is there anything at all?".

References

{{reflist Perception Ontology Quantity

Scope

In theoretical physics

In philosophy

See also

References