Theory

A theory is a system of statements that is used to describe sections of the reality, or explain, and make predictions about the future.

Translation and etymology

The word theory (Greek θεωρεῖν theorein, observe, look, look [at] '; θεωρία theoria, contemplation, reflection, insight, scientific consideration ', the observation or perception of beauty as a moral category ') originally referred to the contemplation of truth by pure thought, regardless of their realization. Therefore, the term is also used in everyday language as indeterminate opposite of practice (Greek πρᾶξις, action, performing ', also, completion ').

Definition

Depending on the scientific theoretical point of view, the term is explained theory different. In general, a theory draws a picture (model) of reality. In general, it refers here to a specific part of reality. A theory typically contains descriptive (descriptive ) and explanatory ( causal) statements about this part of reality. On this basis, predictions are made. Many scientific theoretical basic concepts and further questions of general policy relating to the theories of reality in general, are discussed in some areas of philosophical disciplines metaphysics and epistemology.

After a positivist understanding of theories associated with the claim to be able to check by observations ( eg by means of experiments or other methods of observation ) ( empiricism ). This observation then yields directly the truth or falsity of the theory, ie verifies it ( confirmed ) or falsified the theory.

In the logic of theory refers to a deductively closed set of formulas in the simplest case. There is usually also strictly formal, mathematical- logical definition of the concept of theory: A set T of statements in a language is said to be theory if T is satisfiable and if every sentence that follows from T, already belongs to T. In simple terms, you must at all may be true, and also self-contained and be consistent.

Various problems have led to more complex concepts of theories and the expressive quality of observations have been developed in recent decades. These discussions relate particularly the clarification of a term of confirmation and are closely related to problems of induction, causality and probability.

From the specific perspective of the skeptic movement only empirical statements may be referred to as theories. It does not include, for example, a tautology or definition. Theories whose empirical testing according to current knowledge absehbarerweise is not possible, but would be potentially possible, they referred to as " speculative" and assigns them to the para-science. Theories that say something about the way of the world, without an observation to offer, they confirmed or refuted if necessary - so do not include any statements of their decidability - are from this point of view is not part of science. You can either use the pseudo-sciences, for example, or religion (or esoteric ) are assigned. Furthermore, to divide theories in everyday theories and scientific theories, the latter having a higher degree of awareness on, explicit formulation, larger scale and involve the most systematic observation. According to this view, the theory is a more or less clear and well -formulated hypothesis was confirmed.

According to the classical view can be derived from predictions of theories turn recommendations for action. Thus, the theory forms the basis for the practice resulting from it.

After the critical and rational view everyday theories and scientific theories are epistemologically indistinguishable from each other and all theories are equally speculative. The latter are merely as a rule closer to the truth and hypotheses are less general theories. From theories, no recommendations can be derived, but only criticize recommendations it. Theory and practice form from this perspective contrasts.

Quality criteria

Minimal demands on theoretical models have in general that they comply with the rules of logic and grammar, consistent ( internally consistent) and are verifiable. The prerequisite is that the terms used

A good theory should continue

• Be compatible with already proven older theories or they include even in your own declaration area;
• Have explanatory value, eg not be purely descriptive;
• Forecasts allow that actually occur in practice and thus be falsifiable;
• Be extensive, her subject area so should not be too specific;
• Fertilize, so inspire other scientists to further research.

Other important claims on theories include the ability to specify the axioms of a theory, as well as the " expressiveness " of a theory: Is it possible the theory to describe finitely / countably many axioms, it is called finite / countable axiomatizable. A theory is called ( negation ) complete if and only if every set of its underlying language or its negation are elements of the theory.

Constituents of theories

Science theory, it is largely common to distinguish between the following possible elements of theories:

• Basic assumptions: These are statements about the fundamental structure of reality and how we should investigate them. They underpin all key messages. These may metaphysical (about transcendent statements about the existence and role of God, gods, spirits, etc.), cosmological and biological assumptions ( statements about the structure of animate and inanimate nature ), anthropological ( statements of what people are) so as epistemological and pragmatic assumptions and requirements ( such as information about can be achieved as in the respective subject area knowledge, as scientists should work ) fall. The totality of these assumptions makes an important aspect of the what is sometimes called, building on Kuhn paradigm, and the Lakatos'schen concept of " research program".

• Basic concepts: These are the "building blocks " of the theory (which can be theoretical terms such as physical quantities and entities ).

• Theory Core: This is in the descriptive and explanatory statements. The explanatory statements are also called hypotheses, these are often referred to as if-then statements formulated or even more formalized. In addition, can be part of a theory prognostic statements and make recommendations.

• Measurement concepts: assumptions be made measurable by indicators ( operationalized ) to be tested empirically, for example this can be done by asking a question in a questionnaire.

• Empirical evidence: observations that are to confirm or disprove a theory.

In scientific practice theories containing these elements in highly varying degrees; this depends amongst others, the cognitive interest of the respective working scientifically.

• Descriptive and explanatory statements may be weighted differently: some theories, the description takes precedence, in the other explanations, others strive for a balance. A preponderance of descriptive statements often include theories that explore a new area of ​​research.

• Prognostic and make recommendations statements are made by some scientists do not, or only with extreme caution, while others consider this as the main purpose of their work ( for example, the application-oriented natural sciences or social scientists in policy advice ).

• A big difference exists between scientists who create their theories strictly on empirical verification, and those who do so less or not. The former endeavoring to find plausible ways to formulate their hypotheses verifiable to make measurable and test them empirically. Therefore, there are theories and such ( almost) without clear hypotheses, indicators and empirical evidence.

Examples

• Physics: The predictions of classical mechanics and special relativity, for example, differ significantly when the viewed objects moving at speeds approaching the speed of light. In everyday life, one can not determine the differences, since classical mechanics is the limiting case of special relativity, if the speed is much less than the speed of light. Therefore, the classical mechanics is the appropriate theory in everyday life.
• Geometry: For each a straight line and a point not on this line, there is exactly one parallel line through this point. This statement has long tried to infer from the other axioms of geometry. The fact that we could show that the geometry in which the parallel statement is not true, lead to meaningful models, had proved that the parallel statement independent of the other axioms of geometry axiom (see non-Euclidean geometry).
• Mathematics: The mathematician Georg Cantor had proposed a naive, that is, informal definition for the term set. The resulting theory, although he recognized as contradictory (see Cantor's antinomy ), yet there is enough in the school mathematics to work with this informal set theory. Mathematicians usually use the formal theory of Zermelo -Fraenkel set theory (whose consistency but is not provable ).
• The concept of middle-range theory developed - In sociology was - for the social sciences generally.

A theory can also be a purely algorithmic methods, such as the planetary theory to calculate the positions of celestial bodies.

Other aspects of the concept of theory

The methodical way in which such theories come about, so how is taking place, the growth of knowledge is controversial. In the further development of theories is sometimes made ​​between induction, deduction and abduction:

In theory, by induction, it is assumed that the scientists developed data material in the empirical process in which, finally, internal structures and regularities are visible. More positive-going experiments will confirm the theory and are the building blocks of verification ( proof ) that ultimately in the laws of nature Safety ( consistency ) is to lead.

In the theory by deduction, it is assumed that the scientist creates through creative acts of meaningful hypotheses for which compliance with the data material he subsequently checked. Further experiments need to be undertaken with the serious aim of falsification ( refutation ). ( Avoid the falsification ) Only to the extent as to prove theories, relative safety can be obtained.

The Abduction includes present from a result and a possible or spontaneously formed rule on a case. To make a surprising phenomenon explained, a rule is hypothetically introduced, so that the result can be considered as a useful case this rule. Abductively lessons learned may be right, but do not need it.

In the practice of science, inductive and deductive elements mix with no problems, so that this question has a more epistemological and ideological significance.

Provides the science with its theories a way to absolute truth or to a gradually taking place closer to the truth ( which you never can be quite sure ) or is not truth of the sciences or is there any truth to it? The second, which goes back to Karl Popper position is currently preferred by the majority of scientists who first applies - due to fundamental insights about observability - as outdated.

In everyday language, the term is " just a theory " most often understood in the sense of and then simply refers particularly uncertain findings. This has not much to do with the scientific definition of theory and often leads to misunderstandings. For example, does not mean the term " theory of relativity " that the findings were not backed up. Of course, it is in principle falsifiable, so could not be true, but the partial word " theory " characterizes them solely as " internally consistent " and distinguishes it from the Newtonian theory - classical mechanics - from.

Relationship between theory and question

Without theory, there are no methods and measuring instruments, so there are methods and measuring instruments only based on theoretical assumptions, not independent of them. A question again stands at the beginning of the process to select a theory on the basis of those factors are filtered out, which will be critical in collecting data. The choice of theory, which is based on, and the question at the beginning of a research process that is closely related. From the theoretical perspective, which is taken as the inquiring person the choice of subject depends on the specific cognitive interest, for which method you choose and the results of the study, an assessment of the communication sciences.