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.
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.
One common scenario is for people to give a lot of weight to unproven theories or to risk factors that make a relatively small contribution to cancer, but at the same time to ignore or minimize the cancer risk posed by other factors that really do have an impact.
... "conspiracy" theory that more than 500,000Americans have not actually died from the virus ... George said he is unsure whether the vaccines are actual vaccines, citing unproven theories that Bill Gates is behind the engineering of it or the government is experimenting on people.
The theory was that this setup would drastically reduce aerodynamic drag ...There are no known records of a wind-tunnel model ever being made, but the experimental fighter was part of a series of projects designed with the object of developing new and unproven aerodynamic theories.
George is unsure whether the vaccines are actual vaccines, citing unproven theories that Bill Gates is behind the engineering of it or the government is experimenting on people ... "They can melt liquid metal and put it in a shot and then tell where you are at every minute," he said citing one theory.
My arm is sore, my fever finally broke, and my bottle of Advil is emptied ...There is satisfaction in knowing I contributed to kicking the dickens out of COVID ... When I read an unproven theory about vaccines’ dangers, following the science, or folks pitting politics against medicine, I wonder how those who espouse such beliefs are even alive ... ....
... mandates based on unproven, unethical research dangerous to women’s health ... “In no other area of medicine would we force a provider to violate acceptable standards of informed consent and provide inaccurate and harmful information to a patient about an unproven theory.”.
Let's be blunt. America's had an absolutely terrible pandemic ...Donald Trump. The recently ousted president handled this crisis catastrophically badly – refusing to take it seriously from the start when it erupted last February, ignoring the science, publicly shaming his top medical experts, and spray-gunning dangerous unproven 'cure' theories ... Fauci...
For years, the loudest voices in the anti-vaccination movement were environmentally conscious liberal parents who embraced unproven theories that vaccines caused autism and could lead to other health risks. But in recent years, the focus has changed ... Advertisement ... “Progressive, Republican ... whatever, it’s not even about that,’' said Rep ... Rep ... » ... .
For the home to the world’s second-largest Covid-19 outbreak, life in India is almost back to normal. Shopping mall parking lots are full again ... Read More ...Others have also pointed to India’s youthful population or to unproven theories that widespread exposure to a high number of tropical diseases confers some protection against Covid.
London/New Delhi — For the home to the world’s second-largest Covid-19 outbreak, life in India is almost back to normal ...Others have also pointed to India’s youthful population or to unproven theories that widespread exposure to a high number of tropical diseases confers some protection against the coronavirus ... Bloomberg .