Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context, the results might for example include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several different related meanings. A theory is not the same as a hypothesis. A theory provides an explanatory framework for some observation, and from the assumptions of the explanation follows a number of possible hypotheses that can be tested in order to provide support for, or challenge, the theory.
A theory can be normative (or prescriptive), meaning a postulation about what ought to be. It provides "goals, norms, and standards". A theory can be a body of knowledge, which may or may not be associated with particular explanatory models. To theorize is to develop this body of knowledge.
As already in Aristotle's definitions, theory is very often contrasted to "practice" (from Greek praxis, πρᾶξις) a Greek term for "doing", which is opposed to theory because pure theory involves no doing apart from itself. A classical example of the distinction between "theoretical" and "practical" uses the discipline of medicine: medical theory involves trying to understand the causes and nature of health and sickness, while the practical side of medicine is trying to make people healthy. These two things are related but can be independent, because it is possible to research health and sickness without curing specific patients, and it is possible to cure a patient without knowing how the cure worked.
The game of chess is commonly divided into three phases: the opening, middlegame, and endgame. There is a large body of theory regarding how the game should be played in each of these phases, especially the opening and endgame. Those who write about chess theory, who are often but not necessarily also eminent players, are referred to as "theorists" or "theoreticians".
"Opening theory" commonly refers to consensus, broadly represented by current literature on the openings. "Endgame theory" consists of statements regarding specific positions, or positions of a similar type, though there are few universally applicable principles. "Middlegame theory" often refers to maxims or principles applicable to the middlegame. The modern trend, however, is to assign paramount importance to analysis of the specific position at hand rather than to general principles.
The development of theory in all of these areas has been assisted by the vast literature on the game. In 1913, preeminent chess historian H. J. R. Murray wrote in his 900-page magnum opus A History of Chess that, "The game possesses a literature which in contents probably exceeds that of all other games combined." He estimated that at that time the "total number of books on chess, chess magazines, and newspapers devoting space regularly to the game probably exceeds 5,000". In 1949, B. H. Wood opined that the number had increased to about 20,000.David Hooper and Kenneth Whyld wrote in 1992 that, "Since then there has been a steady increase year by year of the number of new chess publications. No one knows how many have been printed..." The world's largest chess library, the John G. White Collection at the Cleveland Public Library, contains over 32,000 chess books and serials, including over 6,000 bound volumes of chess periodicals. Chess players today also avail themselves of computer-based sources of information.
In mathematical logic, a theory (also called a formal theory) is a set of sentences in a formal language. Usually a deductive system is understood from context. An element of a theory
is then called an axiom of the theory, and any sentence that follows from the axioms (
) is called a theorem of the theory. Every axiom is also a theorem. A first-order theory is a set of first-order sentences.
When defining theories for foundational purposes, additional care must be taken and normal set-theoretic language may not be appropriate.
The construction of a theory begins by specifying a definite non-empty conceptual class , the elements of which are called statements. These initial statements are often called the primitive elements or elementary statements of the theory, to distinguish them from other statements which may be derived from them.
A theory is a conceptual class consisting of certain of these elementary statements. The elementary statements which belong to
are called the elementary theorems of
and said to be true. In this way, a theory is a way of designating a subset of
which consists entirely of true statements.
Praxis is an educational program that aims to teach entrepreneurship to young people and that a traditional college education is not the only way to success. Praxis was founded by Isaac Morehouse in 2013.
After interacting with businesspeople and students while working for an educational nonprofit, Morehouse noticed a skills gap between recently-graduated college students and employers. Having been homeschooled himself and then exposed to a university-education, Morehouse noticed the disparity in skills taught and skills demanded by the professional world, as well as the frustration faced by students who expected a job upon graduation. This led Morehouse to realize that most of the perceived value of a college degree comes from its value as a signaling mechanism, showing employers that a candidate is superior to those without the signal. Employers told Morehouse that a lack of work experience was the primary reason they did not hire candidates with college degrees. The lack of the strength in the signal led Morehouse to found Praxis in 2013 as an alternative signal for employers and students, combining a traditional liberal arts education with work experience than that which is gained in college.
Praxis was the name of an experimental rock project, led by prolific producer/bassist Bill Laswell and featuring guitarist Buckethead and drummer Bryan "Brain" Mantia in nearly every incarnation of the band.
The group worked with many other artists such as Serj Tankian from System of a Down, Iggy Pop, DXT and DJ Disk.
Bill Laswell initially used the name Praxis for an experimental solo EP recorded for Celluloid Records in 1984, simply named "1984".
The band's debut album, Transmutation (Mutatis Mutandis), released in 1992 was well received by critics. Praxis was composed of Buckethead, keyboardist Bernie Worrell drummer Brain, bassist Bootsy Collins and Afrika Baby Bam as AF Next Man Flip on turntables. Bill Laswell masterminded the project and served as producer and co-writer of much of the album's material. Praxis combined elements of different musical genres such as funk, jazz, hip-hop and heavy metal into highly improvised music. The P-Funk-inspired track "Animal Behavior," with a lead vocal from Collins, was released as a single. A video was also shot for the track.
M-113 – a Class M planet featured in TOS episode "The Man Trap". The planet is also called Crater's World, and also known as Fotialla by the extinct natives that once lived there.
M'kemas III – Tzenkethi settlement attacked by Ambassador Krajensky (a disguised changeling) who commandeered the USS Defiant in an attempt to start a war with the Federation.
M-S-1
M-Zed V – Mentioned in TNG episode "Heart of Glory". It is an outpost possibly under Klingon control. It was claimed as the destination of Korris and his fugitive Klingons. Note: It may simply be spelled as M-Z-V as "Zed" is the typical British/Canadian pronouncement of the letter "Z" instead of "zee".
Mab-Bu VI – Gas giant planet with a Class M moon. In the 19th century, criminals from the Ux-Mal system were exiled to the moon where their consciousness was separated from their physical bodies by the planet's electromagnetic fields. Some time in the 2160s, the prisoners attempted to escape by inhabiting the bodies of crew members of the Federation starship USS Essex but the plan failed when the ship crashed on to the surface. The beings later take possession of Data, Troi, and O'Brien to hijack the Enterprise-D.