Main Difference
The main difference between Fact and Theory is that the Fact is a statement that is consistent with reality or can be proven with evidence and Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking
Fact
A fact is a thing that is known to be consistent with objective reality and can be proven to be true with evidence. For example, “this sentence contains words” is a linguistic fact, and “the sun is a star” is a cosmological fact. Further, “Abraham Lincoln was the 16th President of the United States” and “Abraham Lincoln was assassinated” are also both facts, of the historical type. All of these statements have the epistemic quality of being “ontologically superior” to opinion or interpretation — they are either categorically necessary or supported by adequate historical documentation.
Conversely, while it may be both consistent and true that “most cats are cute”, it is not a fact (although in cases of opinion there is an argument for the acceptance of popular opinion as a statement of common wisdom, particularly if ascertained by scientific polling). Generally speaking, facts transcend belief and serve as concrete descriptions of a state of affairs on which beliefs can later be assigned.
The usual test for a statement of fact is verifiability — that is whether it can be demonstrated to correspond to experience. Standard reference works are often used to check facts. Scientific facts are verified by repeatable careful observation or measurement by experiments or other means.
Theory
A 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 related meanings.
Theories guide the enterprise of finding facts rather than of reaching goals, and are neutral concerning alternatives among values. 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.
In modern science, the term “theory” refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support (“verify”) or empirically contradict (“falsify”) it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge, in contrast to more common uses of the word “theory” that imply that something is unproven or speculative (which is better characterized by the word hypothesis). Scientific theories are distinguished from hypotheses, which are individual empirically testable conjectures, and from scientific laws, which are descriptive accounts of how nature behaves under certain conditions.
Fact (noun)
Action; the realm of action.
Fact (noun)
A wrongful or criminal deed.
“He had become an accessory after the fact.”
Fact (noun)
A feat or meritorious deed.
Fact (noun)
An honest observation.
Fact (noun)
Something actual as opposed to invented.
“In this story, the Gettysburg Address is a fact, but the rest is fiction.”
Fact (noun)
Something which is real.
“Gravity is a fact, not a theory.”
Fact (noun)
Something which has become real.
“The promise of television became a fact in the 1920s.”
Fact (noun)
Something concrete used as a basis for further interpretation.
“Let’s look at the facts of the case before deciding.”
Fact (noun)
An objective consensus on a fundamental reality that has been agreed upon by a substantial number of experts.
“There is no doubting the fact that the Earth orbits the Sun.”
Fact (noun)
Information about a particular subject, especially actual conditions and/or circumstances.
“The facts about space travel.”
Fact (noun)
An individual value or measurement at the lowest level of granularity in a data warehouse.
Fact (interjection)
Used before making a statement to introduce it as a trustworthy one.
Theory (noun)
Mental conception; reflection, consideration. 16th-18th c.
Theory (noun)
A phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc. from 17th c.
Theory (noun)
The underlying principles or methods of a given technical skill, art etc., as opposed to its practice. from 17th c.
Theory (noun)
A field of study attempting to exhaustively describe a particular class of constructs. from 18th c.
“Knot theory classifies the mappings of a circle into 3-space.”
Theory (noun)
A hypothesis or conjecture. from 18th c.
Theory (noun)
A set of axioms together with all statements derivable from them. Equivalently, a formal language plus a set of axioms (from which can then be derived theorems).
“A theory is consistent if it has a model.”
Fact (noun)
a thing that is known or proved to be true
“the most commonly known fact about hedgehogs is that they have fleas”
“he ignores some historical and economic facts”
“a body of fact”
Fact (noun)
information used as evidence or as part of a report or news article
“even the most inventive journalism peters out without facts, and in this case there were no facts”
Fact (noun)
used to refer to a particular situation under discussion
“despite the fact that I’m so tired, sleep is elusive”
Fact (noun)
the truth about events as opposed to interpretation
“there was a question of fact as to whether they had received the letter”