Occam's razor
Occam's razor (also principle of parsimony, lex Parsimoniae or parsimony ) is a heuristic principle of research from the scholasticism which dictates frugality in the formation of explanatory hypotheses and theories. It still finds application in the philosophy of science and the scientific method. When you are facing the choice of several possible explanations for the same phenomenon, one should prefer the one that manages to hypotheses with the lowest number and thus the " easiest " is theory. It also includes the requirement to recognize only one reasonable explanation for each investigation.
In simple terms, it states:
The ockhamsche principle demands that you no longer hypotheses and variables introduced in declarations to be used as needed to derive the facts to be explained adequately. This leads to criteria for original research. The practical advantage is intended to be that theories with a few simple assumptions can be easily falsified than those with many and complex assumptions. It is a principle which is a criterion for the quality of theories only and allows no judgment on the validity of explanations without further notice.
The " razor " can be understood as a metaphor: the simplest and at the same time suitable explanation is preferable to all others are cut off with a razor.
Historical formulation and Name
In his famous formulation, it reads: " Entia non sunt praeter multiplicanda necessitatem [or sine necessitate ] " ( German: "Entities should not be multiplied beyond necessity. " ) This was built in 1645 by the philosopher John Clauberg ( 1622-1665 ) coined. In the form of "non sunt entia sine necessitate multiplicanda " this principle has already been cited in 1639 by the Scotists John Poncius as scholastic maxim.
The English name is Occam 's Razor (or ontological parsimony ), the Latin novacula Occami, the traditional German Occam's Razor; Condillac in 1746 we find the French formulation rasoir of nominaux.
This rule was named in the 19th century by William of Ockham ( 1288-1347 ), although Ockham himself never explicitly established and named such a principle, but probably used implicitly in his writings. So he asked: "Nothing we may assume without own reasoning, unless it was obvious or known or backed by the authority of Scripture on the basis of experience." (In I. Sent d 30, q 1) The term Occam 's Razor for this principle of economy emerged only in the 19th century when mathematician William Rowan Hamilton and gained in the run of John Stuart Mill discussion about the philosophy of science dissemination.
History
The idea to prefer the simplest explanation, goes back to Aristotle. Mostly it was justified that nature always choose the easiest way. Ockham rejected this justification from but since they collectio Limit the omnipotence of God. Such a limitation of the divine will he not accepted, according to Ockham, God might as well choose the most complicated way. It is not nature itself, but rather theories should satisfy the principle of economy. In theory construction are redundant elements eliminated and the easier of the two possible theories that can explain both the same phenomenon can be selected. In Ockham thus is an originally ontological law to a practical rule for the theory of knowledge.
In the modern philosophy of science, there are different interpretations of " Occam's Razor ", which should justify it as a rational research maxim. Thus was brought, among others, simplicity with a higher degree of confirmation or declaration in connection with the best. Also, a higher a priori probability within the Bayesian probability based term favoring simpler theories. Against such justifications is argued that they are circular if they have no independent criterion for the simplicity of theories. Moreover, it is due to the problem of induction is not possible, one of several theories that are equally compatible with all the facts given as true or probable reward, regardless of how complex it is.
Want to avoid Present reasons, the circularity and the problem of induction, interpret Occam's principle, therefore, as a " search strategy " or heuristics: By the principle is used to select between various, compatible with the data declarations repeatedly, is to be an approximation to a true general theory. In addition, Occam's Razor is robust, in that cause individual deviations from the rule anyway for convergence to the true theory when you returned after a successful injury to Ockham'schen rule. This robustness is important because the rule is apparently not strictly applied in scientific practice, and is rarely clearly determined in the individual case, what is meant by " easy " to understand. However, it can also be shown that the strict application of Occam's razor under all alternative rules, which would also lead to convergence to the true theory, is distinguished by the fact that it represents the most efficient rule.
Another non-circular justification of Ockham'schen principle is based on the observation that ignorance of the correct theory predictions with a high hit probability can be made even with false theories, methods and that the complexity of the selected for forecasting theory in the accuracy of predictions of a role plays. The use of simple models in the presence of random noise in the data, can even lead to more accurate predictions.
Principle of parsimony principle of diversity instead of
Walter Chatton was a contemporary of William of Ockham advocated a counter-position to Occam's parsimony principle: Although various other philosophers "If three things are not enough to make a clear statement about something, you have a fourth will be added, and so on. " In have formulated similar "Against principles " this time, this did not alter the significance of ontological parsimony principle.
Gottfried Wilhelm Leibniz (1646-1716) formulated a principle of diversity: According to Leibniz why we happen to live in the best of all possible worlds, because this produces the greatest variety of life, and not because this would be as free from evil, sin and suffering; So it is a principle of the optimum of completeness (see also theodicy ). For definitions and explanations Leibniz nevertheless took the view, however, that the simplest explanation is the best.
Immanuel Kant (1724-1804) formulated a principle according to which the diversity of natural species should be prematurely reduced by a reductionist explanation ( Immanuel Kant: AA 0003III, 428-441 ), but recognized at the same time the attempt at such a reduction by the focus imaginarius the ideas of reason as an interest of reason ( s Transcendental dialectic ). Karl Menger (1902-1985) referred to mathematicians as too stingy when dealing with variables and formulated his law against poverty in two forms: "Entities must not be reduced to the inadequacy [ and ] it is pointless to do with fewer what requires more ".
In fact, it is so that Occam's razor can only be recognized if several theories are available that can provide the required statement at the same depth. A complicated theory better explain the object, can therefore be a simpler preferred. Thus, the theory of relativity is more complicated than classical mechanics, since they considered various forces in complex mathematical relationships, but they can also explain a larger domain of phenomena.
One of the applications of the diversity principle was the Ptolemaic world view: The more accurately the astronomical observations were, the more clearly evaded the stars and planets of the predicted positions from. To the deviations, apparent returns and another with the classical metaphysics of Aristotle, who had made the Church for binding doctrine explain, constantly had to be included in the model more epicycles. Then the earth was at the center of concentric celestial spheres on which moving the heavenly bodies. The worldview of Nicolaus Copernicus represents an attempt to eliminate these epicycles and to model the movements of the planets evenly. But he put the celestial spheres around the sun, the planets new orders and joins the earth in the order of the planets a. Copernicus did not have to so look for reasons for the epicycles. First, however, this model agreed worse with the observed data match as the improvement of the geocentric world view developed by Tycho Brahe. Comparable agreement brought the replacement of the circular paths by ellipses in Kepler's laws. But it was only with the introduction of gravitation as a construct by Isaac Newton was the heliocentric worldview claim to be the simpler theory, since Kepler's laws could now be deduced from the general laws of physics, which Galileo had set up and confirmed experimentally. Although the geocentric worldview described the positions of the stars and planets as precisely, but could justify he postulated movements of the heavenly bodies is difficult physically or metaphysically.