rationality

Rationality describes reason-based thinking and acting . It is aligned with purposes and goals . Reasons that are considered reasonable, are deliberately selected.

The expression comes from the Latin rationalitas ('ability to think'), derived from ratio (' calculation ', ' reason ', 'understanding', also 'relationship', '(logical) reason', 'justification reason', 'reasoning'). Rationality can have different meanings , depending on the scope and what is considered reasonable . In modern times we therefore speak of different rationalities of one reason.

meaning

On the concept of rationality

When analyzing the concept of rationality, various aspects can be in the foreground:

First, it is a certain relationship between what should be the purpose and the means employed to attain it addressed. Here, rationality means the ability to estimate a cause-effect chain. It is about the descriptive answer to the questions: "Which means works - or how does the chosen means work - and how much effort is required to achieve the intended purpose?" The question of the end-means correlation was raised by Max Weber , see Chap. Social sciences . Max Horkheimer speaks here with critical intent of an instrumental reason .
Second, it is about evaluating a purpose as appropriate, and rational then means “reasonable”, “right”: the concept of rationality is thus used to justify certain principles that are intended as norms . Here rationality asks not only whether something is being done right ( efficiency ), but whether the right thing is also being done ( effectiveness ). Sensible action thus includes a right to act correctly, which can be justified. The invitation to act sensibly is prescriptive and is formulated as a hypothetical imperative . In many situations, acting unreasonably is considered inferior. According to Max Weber ( see below ), whoever maximizes the ratio of benefit and effort when choosing the right goal acts purposefully .
Third, patterns of evaluation and patterns of development processes are referred to as the “rationality” (sometimes also called “logic”) of a process or system. Rationality here is an expression of methods and procedures. System rationality describes an optimal functional context. The main concern here is the consistency of arguments, decisions and actions. “ Cognition , evaluation and action must form a unit.” This area of the term field also includes the characteristics and abilities of people. One speaks of rational people. From a critical point of view, this turns people into a system or a thing that works.
Fourth, the term rationality or “rational” is used as an explanatory model for actions, beliefs, wishes or norms. An id S. “rational explanation” of a certain action or belief tries to make it intersubjectively understandable - by specifying the respective (action-) situation-specific conditions , i. H. to make it understandable for other people. The explanatory analysis asks about the conditions and motives of rational action. What is considered rational here is what is well-founded , appropriate and justifiable. In contrast to instrumental or purpose-oriented rationality, one can speak of a substantial or moral rationality here. Max Weber described this aspect of the term as value rationality, which follows a moral, religious or aesthetic attitude and is expressed in an ethic of conviction .

In contrast to the concept of reason , one can form the plurality of the concept of rationality and speak of different rationalities . The counter-concept to rationality is the irrational , a state or an action that is not supported by reasonable reasons ( affects , wishful thinking, abnormal psychological states, e.g. paranoia ). Inanimate objects and plants are neither rational nor irrational, but arational , that is, incapable of rationality. With regard to animals, especially higher mammals, it is controversial to what extent they are capable of rationality. A distinction is made between the pragmatic rationality oriented towards actions and the theoretical or cognitive rationality, which has knowledge as its object. It includes “all types of methodical thinking in a finite number of reproducible steps to obtain and justify statements about the world.” Cognitive rationality can only claim validity if the knowledge can be justified and verified by other people. Rationality is closely linked to the concept of intentionality because it is always directed towards something (a person, a state of affairs). A person can be called rational if he meets the evaluation criterion of “good reasoning”.

Many classical philosophers differentiate between ratio and intellectus , in German mostly with understanding and reason (originally exactly the other way around), whereby ratio usually represents a lower cognitive faculty that operates comparatively and discursively, while intellectus denotes a uniformly integrated faculty.

In everyday life one cannot speak absolutely of rational or irrational because experiences and habits always have an influence on behavior, i. H. Rationality depends on who expresses a belief or acts on it and when this happens. The judgment of a layperson about a symptom of a disease can be rational, even if the attending physician sees the facts quite differently as a specialist. Arguments, decisions and actions as well as the resulting states and structures are not objective, but only more or less rational in comparison to corresponding alternatives. Thus, rationality is not linked to the concept of truth . Rational can also be an opinion or an action based on a factual error. A principle would be absolutely rational if it could be asserted with a claim to ultimate justification, i.e. a scientific theory that could no longer be falsified (justified as inaccurately justified), or a moral rule that could claim universal (general) validity . Rational practice in the sciences also means orienting oneself towards knowledge that is free of doubts with regard to the information available, even if it remains fundamentally doubtful. Action is rational if it is well-founded and coherent .

Rationality is still not to be equated with success, even if the striving for rationality is motivated by the striving for greater success. Action that worsens an existing situation is not considered rational. The concept of rationality thus includes a benefit associated with an object or an action. The “rational” attribute does not yet indicate the extent to which the benefit exists. The term as such is semantically formal. A “rationally constructed cup” needs different properties for religious applications than a cup for space travel. The word rationality as a description of a property ( predicate ) does not denote an equivalence relation (equivalence relation ) which can be defined by a simple rule, but emphasizes the special suitability for a certain purpose. What is rational in concrete terms only emerges in the respective situation.

An important aspect of rationality is the predictability of action results. This lies in the understanding that a rational belief or action can be justified. An acceptable reason is only possible if the effect of an action was foreseeable beforehand. This requirement becomes problematic because there is always uncertainty about a possible success. “In its nature or essence, the world is neither stable nor certain.” As a result, the risk calculation becomes part of the justification, whereby a prior determination is required as to which risk is to be assessed rationally and how. In this way, from the discussion of rationality, a discussion of responsibility emerges, particularly with regard to the effects of modern mass society and the large-scale technologies it uses. The Polish philosopher Wieslaw Sztumski refers to the limits of rationality, "because at a corresponding stage of development it becomes a hindrance to further development", since "in a world that is changing ever faster and in view of growing uncertainties and risks, the range of application of rationality is becoming more and more narrow" because the "maximizing of rationality (especially in the sense of scientism ) [...] entails different threats to people and [...] the risk of the non-survival of humanity". Sztumski therefore expresses the hope that "a restriction in the 'hunt for rationality' will give us a chance to survive."

Typifications of rationality

In order to get closer to the phenomenon of rationality, Hans Lenk has put together an unsystematic list of concepts of rationality, which can only be freed from overlaps in an analysis and brought into a systematic order.

pure or formal inference rationality (consistency and provability)
hierarchical-architectural rationality
material rationality
rational reconstruction
instrumental middle rationality (purpose rationality)
decision-theoretical rationality (abstract-formal, strategic-game-theoretical, dialogical)
Rationality as a subsequent self-justification
Value rationality
moral rationality (universally deontological)
Rationality of public acceptability
Rationality of understanding
pragmatic compatibility rationality
reflexive rationality
constructivist rationality
scientistic rationality
functionalist rationality
principle rationality (global and local)
occasional rationality (global and local)
complete rationality
incomplete rationality

Nikolaos Psarros distinguishes between

objective rationality, which is given if the degree of goal achievement is measurable (natural sciences, economics, technology, structural sciences, i.e. mathematics, logic, computer science). This is determined by calculation and systematization and relates only to a certain perspective of the living environment .

Conjective rationality, which is characterized by participation in certain practices in the lifeworld that are acquired through experience , such as cultural customs or social rules (in Switzerland you drive on the right side of the road). One example is the “ court society ” examined by Norbert Elias . Knowledge does not arise through theoretical considerations, but through handling. Objective rationality takes place within a conjective environment, whereby it is possible that objective rationality can have priority over the conjective rationality criteria, which can change historically.

distanced rationality that refers to facts that are not only objectively comprehensible and that claim cross-cultural validity. This includes, for example, ethical principles to be clarified in the discourse .

Similar structures can be found in Jürgen Habermas , who differentiates between the pragmatic, ethical and moral use of practical reason, or in Christine Korsgaard , who divides practical reason into instrumental, prudential and moral reason. Nicholas Rescher differentiates between practical rationality (what should one do), theoretical rationality (what one can know) and evaluative rationality (what should one prefer) with regard to the process of decision-making. Karl-Otto Apel contrasts the scientific-technological with the philosophical-transcendental-pragmatic rationality, which he in turn divides into a hermeneutic , ethical and dialectical strategic rationality. Helmut F. Spinner speaks of a "double reason", which on the one hand, as "basic reason", is directed towards general principles, on the other hand, as "occasional reason", is primarily aimed at non-scientific pragmatic issues.

Karen Gloy suggests a systematic classification according to categories, which in turn can be structured differently:

Paradigms (transcendental-philosophical, transcendental-pragmatic, hermeneutical, phenomenological or epistemological)
Applications (theoretical, practical, aesthetic or nature, history, society, science and myth)
Structures (science type, practice type, art, myth or natural sciences versus humanities)

Rationality as a Method

If one understands rationality as a procedural principle, then rational action can be structured methodically. Formulated there results a complete concept of a philosophy of science . There are three basic steps to be distinguished.

First of all, the question has to be analyzed and the problem to be formulated.
In the second step, an analysis of the possible courses of action is carried out, which enables a problem solution at all.
Thirdly, the options for action are evaluated and the selection of the optimal / adequate approach is justified.

In each of these three basic steps, there is a multitude of concepts that have developed historically and factually.

The differentiation according to how one methodically gains access to an object leads to the following distinction:

mathematical-logical
experimental-empirical
phenomenological-analytical
hermeneutic-historical
constructivist-systems-theoretical

Similarly, with regard to the validity of rational arguments, based on the logic of the sciences in Peirce , the procedure can be divided into:

heuristic - abductive
axiomatic - deductive
descriptive - inductive

Karen Gloy differentiates methodological principles according to the way of thinking on which the structure of the (scientific) material is based.

The linear rationality, which collects in lists, captures the world taxonomically as in biology, geography or in the compilation of disease symptoms. This also includes mathematical tables, from which calculation results can be read, or the historical tables of law on which the applicable rules were collected and published. Historically, this form of rationality marks the beginning of systematic thinking. The visual reality is shown serially or additively as it is experienced. The structuring according to general terms (genus, species, subspecies, ...) has only developed gradually. Another step in history was the systematisation of existing and missing features, presented by Francis Bacon in the Novum Organum , with which connections can be made clear through inductive reasoning.

The dihairetic rationality is expressed in formal logical and mathematical thinking. Dihairesis is an analytical and not a synthetic method of hierarchical definition, which includes the application of the logical laws of thought (in particular the proposition of the contradiction to be excluded and the excluded third party ), which follows a principle that as a conclusion either negates the one or the opposite, the former Recognizes statement as true. The consistency of dihairetic derivations can be checked with the help of syllogisms . Because this procedure does not take into account the dimension of time, it cannot grasp the process of reality. It also requires arbitrary classifications so that the quality of the analysis depends on the skill of the analyst. Furthermore, due to the hierarchical principle, the juxtaposition of several equivalent alternatives cannot be represented. The derivation of mathematical propositions also corresponds to the logic of Dihairesis, in that the axioms posed by hypotheses are deductively derived from if-then constructions.

The dialectical rationality is based on the figure of thought of self-reference ( self-reference ). An object (an “A”) and what is different from it (the “Not-A”) are considered, as well as the “A” with reference to the “Not-A”. The dialectic is based on the triad of thesis, antithesis and synthesis, whereby the relationship of the part to the whole, its differences within a genre, are recorded both from one's own and from the perspective of others. The dialectical principle includes both a first and a second, the first (apparently) diametrically opposed, statement in the conclusion, so that the proposition of the excluded third is canceled. In dialectics, a whole can be split into a multitude of equally original members and examined with a different focus. This creates a network of relationships that can also map time dynamically. The dialectic corresponds to ideas of the world in a cycle, of the eternal return or as part of an open process of becoming. The dialectic is dynamic and historical because the dialectical triad creates something new in the synthesis by which the old is displaced as past.

The “metaparadoxal” rationality is able to analyze paradoxes on a meta level and to explain them dialectically. Paradoxes arise when something general is absolutized and related to a particular individual through self-application. There are paradoxes of the infinite (e.g. Zeno's paradoxes of multiplicity ), semantic paradoxes (e.g. “I know that I know nothing”) or set theoretical paradoxes (e.g. “A Cretan claims that all Cretans lie “; Russell's antinomy ; reflexive self-awareness; autopoiesis ). The abolition of these paradoxes can take place by prohibiting self-application (Russell) or by introducing a meta-level ( Tarski's definition of truth ). In the sense of the Münchhausen Trilemma , both amount to breaking off a chain of arguments. If one does not want this, one has to assume an open system ( process philosophy , Gödelian incompleteness ). The metaparadoxal rationality shows the aporias , antinomies or paradoxes of human thought and forms strategies to overcome them. In modern philosophy of science, this includes concepts that tie in with the Duhem-Quine thesis , take into account the concept of the falsification of theories, or endeavor to conclude the best explanation .

In the case of analogical rationality, structural features of complex facts are made clear through the abstraction of symbolization. Analogical thinking ranges from myth to the present. A classic example is the ascent or descent in a hierarchical order, symbolized by the metaphor of the ladder ( Plato's allegory of lines ). The opposition is expressed, for example, in the metaphor of light and shadow, day and night for good and bad . Another analogy is that of the circle, which symbolizes the eternal return as a geometric ideal shape , to be found for example in Timaeus with Plato or in the wheel of life of Buddhism. The circular analogy is also based on the parallelization of seasons and ages. As a part, analogies stand for a whole (pars pro toto) that has a complex structure and cannot be grasped with the method of classical logic (true, false). Analogies refer to network-like structures and incompleteness. The rationality of the analogy ignores the “ tertium non datur ” and leads to new, at least three-valued, logics and uncertainty relations ( fuzzy logic , chaos theory , fractal geometry ). This fuzziness is expressed, for example, in an analogy that Wittgenstein coined with the concept of family resemblance and which has a decisive influence on the modern philosophy of language. Gloy refers here to Rescher and Brandom who tried to overcome the limits of classical logic with the concept of “non-standard worlds”. The realm of analogic rationality also includes parables , jokes , games and the tropics in linguistics .

The structuring of types of rationality elaborated by Gloy has a hierarchical structure, which is a reflection of a genealogical development of thought. From simple linear sorting to static opposition and the dynamics of dialectical progression to speculative overcoming of breaks and inconsistencies to a network of being that also captures fuzziness. None of the types of rationality can be dispensed with and none is comprehensive.

Rationality in the modern understanding draws on the concept of autonomous reason from the Enlightenment , i.e. it assumes a freely acting human being who is not bound to the work of a god or the telos of nature or history and is also not causally determined . Even if one does not give a final justification , according to Günter Ropohl , based on Gerhard Vollmer, concrete features of rationality can be named that must be considered when justifying convictions:

(a) the clarity and unambiguity of the linguistic expression;

(b) the intersubjective communicability and discussability;

(c) the theoretical verifiability (methodological traceability and logical consistency);

(d) empirical verifiability (reproducibility and falsifiability wherever possible and indicated);

(e) the analytical precision (e.g. in the delimitation of system elements);

(f) synthetic coherence (compatibility in system contexts);

(g) systemic reflexivity (mediation between analysis and synthesis, between parts and wholes);

(h) critical reflexivity (self-application of rationality)

Ropohl regards the first three points as the minimum conditions of rationality. The feature (h) refers to the fallibility of the concept of rationality itself, which, like every rational argument, is fundamentally to be kept open to new and improved knowledge. From the perspective of technology philosophy, Ropohl postulates a "synthetic" rationality with regard to the complexity of modern technologies, which "includes not only analytical precision but also synthetic coherence and systematic reflexibility."

History of philosophy

Contemplative looking at the rationally ordered world in antiquity

The origins of rationality can be found in the transition from mythical thinking to practical reason, which systematically points beyond the practical lifeworld . Examples are Babylonian astronomy , the irrigation systems in ancient Egypt , Indian logic and the critical questions of ancient Greek philosophy . Silvio Vietta speaks of an invention of rationality and a cultural revolution that took place in the 8th – 5th centuries. Century before Christ radically changed all areas of social life in the sense of a demythization and making it calculable: The invention of science as a quantitative method of understanding natural relationships, as the geometrization of space, the arithmetization of time, the invention of coins and banking, the introduction of measurement techniques also in the aesthetics and in the war technique and also in the change in the role models of men and women. The pre-Socratic philosophy of the ancient Greeks is characterized by the transition "from myth to logos ". The human-like gods and the narrative explanations of reality with images and parables were replaced by the search for a general principle to explain the world. The sacred original thinking turns into a progress of knowledge. The holistic worldview is partly replaced by logifying and quantifying the world. According to Vietta, the mathematical philosophy of the Pythagoreans already indicates the basic form of rational thinking, which, as a quantitative calculation of natural relationships, created the prerequisite for those technologies that have marginalized other forms of culture and are now spreading around the world. While the Pythagoreans still linked mathematics with mysticism , Euclid's elements are completely exempt from this. The logos, “spiritual arithmetic”, had almost completely broken away from the poetic tales of Homer and Hesiod - as with Xenophanes . The general explanatory principle, initially water and air, became more and more abstract, it became the apeiron , the unlimited, in Anaximenes and finally the nous , the objective world reason, the moving spirit, in Anaxagoras , through which all order is determined. The nous is at the same time the supreme mind in humans, with which he comprehends himself holistically as part of the Logos.

The sophists in particular broke away from this perception of the world . In various, thoroughly controversial approaches, they showed that the traditional ideas of a certain order are contradicting themselves and that there are aporias that humans cannot avoid. Some sophists represented a clear relativism and declared man to be the measure of all things ( Protagoras ). This went so far that their rhetoric was not only recognized, but that they were also assumed - for money - to be able to convincingly justify any theory. Critical to the mere Rhetorik and armed art is presented Plato , the Sophists called "mimics of the ways" ( Soph. 268 b, c). The question here is whether knowledge and ethical statements are objective or merely subjective. In many of Plato's dialogues , the sophistic arguments form the platform from which Plato developed his own position or at least a critical counter-position by refuting the arguments (proof by counter-proof - modus tollendo ponens ). A fundamental argument of Plato against the Homo-Mensura theorem was that it cannot be resolved in the case of opposing opinions, that it therefore does not provide a criterion for truth or correctness. One possible solution (without objective absolutism) is shown in the use of language. The meaning of a term must be agreed in such a way that a participant in the conversation can understand it ( conventionalism ). If there is a convention, one can also check the correctness of a use of the term. Thus Protagoras says in the Platonic Theaitet : "What is accepted together is true if and as long as it is accepted" (Theait. 172b). This would amount to an intersubjectively valid concept of truth, to a consensus theory of truth . Plato discusses this solution, but leaves the answer open to Kratylos in the dialogue (Krat. 385d-386a) and advocates an objective concept of truth and values through participation in the world of ideas (truth as true reasoned opinion) as a measure of rational action. In particular, Plato rejected the legal positivism presented as sophistic (“that no ruler is absent if he is ruler” ( Pol. I, 340e). Instead, he determined the content of justice as the basis of law (everyone does what everyone has to do , Pol. 433a).

For Aristotle , who defined man as a rational being ( zoon logon echon ), a happy and successful life consists in an “activity of the soul according to reason or not without reason.” ( EN I 6, 1098a 7-8) The rational is someone who can “think well” about what could be different (EN VI 5, 1140a 1-1 and 26). Good thinking relates to both the creative art ( Techne ) and practical reasonableness ( Phronesis ). Aristotle described what good considerations are in two ways. Practical reasonableness checks, on the one hand, whether means are suitable to achieve a certain goal (EN III 5-7), and on the other hand, whether an individual, an individual action, corresponds to a general, for example a good life (EN VI) . Again and again it is critically pointed out that Aristotle corresponded to the social ideas of his time and attributed a lower rational status to women than to men and based this on biological grounds ( De generatione animalium ).

While Plato and Aristotle tied the good life to an ascent to the spiritual view of the order of the cosmos determined by the nous, knowledge was of the highest value for them as a thinking grasp of the ideas and principles in the world, in Hellenism the focus was on practice. The polis became less important and after the death of Alexander the situation became politically unstable. Above all, philosophy had the task of providing orientation. The Stoa well as the created skepticism and Epicureanism in competition with the traditional schools of the Academy and the Peripatetic . What all three had in common was the search for peace of mind ( Ataraxia ). The skeptics tried not to be confused by false longings for a better world. The rationality of the skeptic is critical questioning. The Epicureans strove primarily for private happiness through moderate enjoyment. They rejected the idea of a reasonably ordered world and put utility and functional rationality in the foreground. With the Stoics, mastery of the passions was at the center of philosophy. The Stoa followed on from the natural philosophy of Heraclitus and viewed nature as a reasonably ordered organism into which humans have to fit. It was therefore rational for them not to quarrel with fate, but to concentrate on what was available to their own actions. It was from this attitude that the Stoics developed the idea that action depends on the disposition and compliance with the obligations arising from it. This included, in particular, following the instinct for self-preservation and striving for self-perfection ( oikeiosis ). Logic and knowledge of nature are not independent purposes, but serve to answer the question of correct action.

“Living a virtuous life is living based on the experience of what happens naturally. Because our own nature is part of the whole of nature. That is why the highest good is a life according to nature, according to our own and the general nature, so that we do not do anything that the general law tends to forbid, namely correct, all-pervasive reason. "( Chrysippos )

Affects can violate the insights of reason, so that their control is one of the primary tasks of a rational life. For the Stoics, rationality was the dominant view of the world and a holistic way of life.

For the Middle and Neo-Platonists , the theory of the soul was at the center of their thinking, because for them the body was only a temporary "housing" for the soul, which is the bearer of the life functions and which after death reconnects to the nous, to the spiritual world of pure thinking and ideas. It is through which the nous works in the world. The soul is realized in its rationality by merging and abstraction of the diversity in thinking into a unity. The divine one is the principle behind the nous. Practical action according to the virtues is an orientation of the philosophical life towards the divine. This doctrine, which was expressed differently by Plutarch , Plotin , Proclus or Porphyrios , was also reflected in Manichaeism and Hermetics .

Connection and detachment of faith and reason in the Middle Ages

A new perspective on rationality emerged with Christianity, whose philosophical ideas were often combined with Platonic thinking early on. In place of the natural order of the nous, however, came the order given by God's creation. The Church Fathers replace the absolutely good Plato with God. The rational practice of Christianity is obeying the divine commandments. Augustine emphasized the proximity to Neoplatonism: “Then they only had to change a few words and views to become Christians themselves. That is what most of the Platonists of our recent times have done. ”( On true religion IV 7, 23) Augustine uses reason above all to purify faith. Perfect faith is reasonable faith. Rational is action that implements the biblical commandments with the means of reason. "We Christians believe and teach, and our salvation depends on the fact that philosophy, that is, striving for wisdom, and religion are not different from one another". (On true religion V 8, 26) Rationality and spiritual belief form a unity for Augustine, which is, however, characterized by the clear primacy of belief.

Especially through the Christian philosophers Boethius and Pseudo-Dionysius Areopagita as well as the late Roman authors Macrobius and Martianus Capella , Christian Neoplatonic thinking was preserved and transferred into the Middle Ages and reached as far as Meister Eckart and Nikolaus von Kues . In the Middle Ages, on the other hand, there began a gradual change in the relationship between belief and rationality. One expression of this is the abolition of God's judgments in 1215 at the Fourth Lateran Council . A particularly important feature is the establishment of the universities , which began at the end of the 11th century. The scholastic method can be understood as a first epistemological concept in which knowledge and sciences were classified.

Already Anselm of Canterbury has tried with his proofs of God demonstrate the necessary reasons (rationes necessariae) for the truth of the Christian faith, which is a spiritual theology by a rational theology supplement. The beliefs that stem from revelation have to prove themselves before the truths of reason. Reason enables the divine order to be grasped correctly. Petrus Abelardus is known for giving reason a more independent position. By showing the contradictions of tradition in his writing Sic et Non (a method that can already be found in Bernold von Konstanz ), he strengthened the position of the master who had to resolve the conflicts through a logically recognized argumentation, so that reason could take on its own importance alongside the teaching of the Church Fathers. By including the demand “ know yourself ” ( scito te ipsum ) in the title of his ethics, Abelard emphasized subjective reason and conviction as the basis of moral action.

Thomas Aquinas made a special effort to bring philosophy and reason into harmony. Even if no properties of God can be recognized with reason, the existence of God can be made plausible with arguments, as Thomas explains in the "five ways to prove the existence of God". This line of argument is the starting point for a rational theology. Reason tells man to do what is good and not to do what is bad. But what is good, people experience through their conscience and this can be wrong. The consequence is: "Any will that deviates from reason, whether right or wrong, is always bad." ( STh I / II 19a.5) Rationality demands to determine which practical commandments contradict reason and these To resolve contradictions. This rules out any unreasonableness based on faith. The same argument led in the Regensburg lecture Benedict XVI. to irritation when he pointed out that Islam does not know reason as a standard for acting according to God's will.

The Aristotle reception based on the newly discovered writings led to the talk of the “double truth”, which arises from the fact that statements according to reason and belief can contradict one another, but nevertheless claim truth in the respective thinking. If this thesis was also rejected by Thomas and was also the subject of the Paris condemnations , it shows approaches to the separation of belief and rationality.

Johannes Duns Scotus took an important step by introducing a newly formulated concept of will into scholastic philosophy. According to Scotus, the will and not reason is the source of rationality, because the will contains opposites, that is, it is the basis of decisions. This applies both to the setting of an end as freedom to will something (libertas specificationis) and to the exercise of will, freedom of action (libertas ecercitii). Reason leads to an unambiguous result, to what is considered right and thus has a necessary result. Only the will and the will relate to possibilities and thus to freedom. On the other hand, the will needs a criterion for action and this provides it with reason by which it can be judged whether something is good or bad (Ord. II d 7). Rationality is therefore the will of what is recognized as good and the overcoming of the purely natural striving. The highest good that reason can know is God's will. So it is no longer faith that determines action, but the will of God recognized through reason, which Duns Scotus accepted with a natural law based on the principle of justice .

The separation of knowledge and belief took place much more sharply with Wilhelm von Ockham , according to which fundamental truths of faith such as the omnipotence of God cannot be grasped with reason and can no longer be known. “Theology is not a science.” God's will in creation is free. The omnipotence of God is subject only to the principle of the exclusion of contradiction . However, this does not mean that there is no order in the world, because creation definitely contains principles and laws that are so because God willed them to be so. But he has the power to shape them differently. The new positioning of reason led Ockham to a strongly nominalistic conception in the universality controversy and also to a sharper and repeatedly emphasized version of the principle of rationality, which has become known as Ockham's razor . “Nothing can be accepted without justification, unless it is evident or known from experience or secured by the authority of the Holy Scriptures.” (In I. Sent d 30, q 1) Correct action is no longer prescribed by God , but is decided subjectively according to human reason. With this, Ockham formulated the new access to knowledge which was developing in his time and for which a justification or empirical experience was required, unless the higher divine order was available as a source. In Ockham's work, rationality is tied to the truth of sentences. The radicalized attitude brought Ockham into conflict with the papacy and forced him to flee to Munich before the impending condemnation, where he continued his work mainly with political and church-critical work. As a result, the difference increased increasingly. B. with Nicolaus von Autrecourt , in the course of a progressive secularization , which was reflected in a new philosophy of the Renaissance and humanism and in the Reformation .

Exploration and mastery of nature in modern times

At the beginning of the early modern era, procedural rationality became increasingly important. Man no longer saw himself bound by the idea of a divine order of nature. Rather, a thinking developed that with increasing knowledge the world could be shaped and one's own life could become more pleasant. The individual subject entered the center of rationality . Francis Bacon set an important milestone . With the leitmotif "Knowledge is power" he called for a critical questioning of possible illusions (idolae) and a collection of understandable knowledge through observation of nature and experiments. An early philosophy of science is the discourse on the method of René Descartes , the inventor of analytical geometry , in which he demanded that theories should be clear and distinguishable (clare et distincte). To achieve this, he formulated four main rules of the method:

Accept as true only what is beyond doubt certain.
Break each question down into sub-problems and simple questions that can be decided with certainty.
Build up the knowledge in turn from the answers to these simple questions and assume such a simple structure for all complex questions.
Check these elements to see if they form a complete order.

In the end, Baruch de Spinoza took the systematic pursuit of scientific research in the formulation of his philosophy to extremes by formulating his Ethica, ordine geometrico demonstrata analogously to Euclid's elements in basic terms, axioms , theorems , demonstrations and corollaries . Even Thomas Hobbes , briefly Bacon's secretary, was interested in intense for scientific questions and mathematics and also tried his philosophical theses after mos geometricus set up as the fundamental principle of rationality.

Consistent with this worldview, the natural scientists of the early modern period tried to fit their new theory into a rational worldview that was no longer dependent on belief. Galileo Galilei is paradigmatic here , who used the formal language of mathematics for his case laws and described the universe as a book written in the language of mathematics.

"The book of nature is written in the language of mathematics and its letters are triangles, circles and other geometric figures, without which it is quite impossible to understand even a sentence, without which one gets lost in a dark labyrinth".

Even Isaac Newton's Philosophiae Naturalis Principia Mathematica are built on the model of Euclid's geometry. The rationality of the 17th century was that of the geometric method, with Newton and Leibniz adding infinitesimal calculus to mathematics so that natural processes could be described in even more detail. Leibniz, in turn, followed Descartes when he demanded clarity and certainty for theories and worked on a Mathesis universalis . The principium rationis sufficientis became a cornerstone of his philosophy. Above all, he pursued the idea of replacing the fuzzy natural language with a universal language based on a formal system of signs (characteristica universalis). With this and with his calculating machine he is at the beginning of a development of logic and computer development towards a modern computer society .

The philosophy of Immanuel Kant is considered to be the climax of reasoning in the Enlightenment . He placed a quote from Bacon before the Critique of Pure Reason and compared his approach with the approach of Galileo and other naturalists:

“When Galileo roll his balls down the inclined surface with a heaviness chosen by himself, or when Torricelli weighs the air, which he had previously thought of as a column of water known to him, [...] all naturalists saw the light. They understood that reason only sees what it produces according to its design, [...] "

By systematically showing the limits of reason, Kant made it clear that one can neither prove the existence of God nor say anything valid about the infinity of the world and that the conception of human freedom must remain a hypothesis. Man is dependent on himself and his experience in his knowledge and actions. There is no knowledge without experience. On the other hand, every human sensory experience is structured through its (conceptual) processing in the mind. In the little script to answer the question: What is Enlightenment? Kant formulated the self-understanding of modern thinking:

Enlightenment is the exit of man from his self-inflicted immaturity. Immaturity is the inability to use one's mind without guidance from another. This immaturity is self-inflicted if the cause of it is not a lack of understanding but a lack of resolution and courage to use it without guidance from someone else. Sapere aude ! Have the courage to use your own reason! is the motto of the Enlightenment.

According to Kant, the rationality of man lies in the fact that he does not follow a speculative reason, but makes use of his understanding and is aware of his limits. The special thing about Kant's philosophy is that he did not get stuck in his criticism of the traditional metaphysics, but presented new philosophical theories with the metaphysical foundations of natural science and the foundation for the metaphysics of morals , which, in his view, with the limits of the human cognitive ability are in harmony. While his concrete natural philosophy is largely considered to be outdated, his draft of a moral philosophy is still being discussed intensively 200 years later.

Relative, social and balancing rationalities in modernity

In the second half of the 20th century, a classic concept of rationality was often criticized; the Enlightenment, for example, was too optimistic about this concept, since it, for example, fades out the bond with vulnerable corporeality and leads to a technicalized total apparatus of existence, individual under general categories conceal or in the sense of a purely technical optimization logic the pursuit of any purpose, including the catastrophes of the 20th century, sanction and optimize. Many philosophers see rationality tied to social practices, especially those of excluding what is considered “irrational”. Well-known philosophers, some of whom appeared explicitly as "rationality critics" or who are assessed as such, are, with very different emphases, Friedrich Nietzsche , Ludwig Klages , Martin Heidegger , Theodor W. Adorno , Max Horkheimer , Michel Foucault , Jacques Derrida and Jürgen Habermas .

Reflecting on the rationality of individual or social practices as well as certain theories is the focus in many areas of philosophy, depending on the approach being followed, often in areas of ethics, the theory of action, social philosophy, philosophy of science and philosophy of religion.

Numerous analytical philosophers have recently attempted systematic elaboration of a concept of rationality, for example Karl-Otto Apel , David Gauthier , Herbert Schnädelbach , Wolfgang Kuhlmann , John Searle , Robert Nozick , Robert Audi , Robert Brandom and Julian Nida-Rümelin .

In Bartley's view, Critical Rationalism feels obliged to provide a theory of rationality, since otherwise it would expose itself to the Tu quoque argument of the irrationalists. In addition, fallibilism requires a theory about how theories should be rationally selected and put into practice.

Economy

In the field of economics, rationality is primarily discussed on the basis of the economic principle , according to which maximum benefit is to be achieved with existing means or a specific goal is to be achieved with minimum effort. The application of this logic corresponds to the basic idea of considering rational action as a value, as it arose in modern times and was formulated in the Enlightenment. Waste is unreasonable. Adam Smith is considered to be one of the most important founders of this thinking . Against the bureaucracy of mercantilism, he had called for more freedom for the individual economic actors. According to his theory, developed in the famous work of the “ Prosperity of Nations ”, the actions of many in a market-based society, which are oriented towards their own interests, lead to a result that also maximizes social prosperity for the economy as a whole. Contrary to popular opinion, however, Smith already saw that a functioning society needs a functioning state that sets the framework for the economy and ensures the freedom of the individual.

Starting from Smith, theories of classical economics , the marginal utility school , neoclassical theory , Keynesianism , the theory of rational decision and finally the new institutional economics developed , each of which attempt to describe model-specific functional and effective mechanisms in open economies. One of the basic assumptions of these explanatory models is that the considered actors act rationally as homo oeconomicus under economic aspects . This means that (fictitious) individuals can be described by a set of options and a predefined order of preferences for the options available. An order of preference is rational when it is both transitive and complete. Mean

Transitivity: Let x, y and z be in the set of choices. Furthermore, let x be at least as good as y and let y at least as good as z. The order of preference defined by the set of choices is rational if, and only if x is at least as good as z, for all x, y and z in the set of choices.
Completeness: An order of preference over a set of options is complete if it is possible for each x and y in this set to say either that x is at least as good as y, that y is at least as good as x, or that both are true.

To act rationally then means that the individual chooses x from the set of choices in such a way that x is at least as good as y, where y is every other element of the set of choices. Note that this is only possible on condition that the order of preference is rational. The frequently widespread view that rationality is synonymous with utility maximization can be justified by the fact that, assuming the continuity of the order of preferences, this can be represented by a utility function to be understood as a model .

Newer theoretical concepts on economic rationality also deal with psychological and socio-psychological influences on individual decision-making. These include behavioral anomalies such as the consideration of lost costs , the underweighting of opportunity costs or the overweighting of property , availability heuristics and striving for security or expectations of self-efficacy , emotions and deviating social preferences. An explanation for this is provided by the theory of limited rationality by the social scientist Herbert A. Simon , who pointed out that decisions are only made rationally to a limited extent due to lack of time, lack of information, inability or other reasons that limit human cognitive abilities.

While the consideration of the economic principle is aimed at the question of how a certain purpose can be optimally achieved, in business ethics it is discussed which purposes are meaningful within economic activity, how one can determine such purposes and ensure their implementation and how one can avoid abuse from market mechanisms. While the economic principle follows a purely formal, instrumental rationality, the discourse of business ethics is geared towards a material, purpose-oriented rationality that takes questions of applied ethics into account.

Social sciences

Max Weber published important works on rationality, including in the field of legal sociology . A distinction is made between the final rationality (expediency) and the material rationality ( legitimacy ) and the formal rationality ( legal certainty ) (cf. also the type of rational rule or the affect-free instruments of rule ).

"Purposeful rational acts who orientate their actions according to purpose, means and side effects, and thereby both the means against the ends, as well as the ends against the side effects, and finally also the different ends against each other rationally."

Weber further distinguished the rationality of purpose from rationality of value. While the rationality of purpose is oriented towards the expected behavior of the outside world and other people, the rationality of values relates to cultural values as motives for action. Weber also transferred the distinction between formal and material rationality to the field of economics. In business and society he distinguished:

“The formal rationality of economic activity should be described here as the degree of calculation that is technically possible and actually applied by it. Material rationality, on the other hand, is to denote the degree to which the respective supply of given groups of people (no matter how delimited) with goods through the type of economically oriented social action is shaped from the point of view of certain (whatever kind of) evaluative postulates under which it has been, will or could be viewed. These are extremely ambiguous. "

The action theory of Talcott Parsons is based on Weber and defines an action as rational, “if it pursues goals that are possible within the conditions of the situation, and when the means available to the agent are essentially best for him Purpose, and for reasons that are understandable and verifiable through positive empirical science. ”With Parsons, the determination of rationality is still very strongly tied to the concept of positive science. Alfred Schütz considered this notion to be an “ archetype of our experience of reality” that was far removed from practice, as was the opposite of “'traditional' or 'habitual' actions”. His objection was that the practice of the lifeworld is much more complex and diverse, so that actions are not justified and decided according to general schemes, but situationally. According to the variety of types of experience, there are many individual rationalities that fit into the respective spheres of the lifeworld.

Niklas Luhmann dealt with the topic, especially in his work Legitimation through Procedure , and pointed out that social decisions are mainly based on the structure of positive law .

The term was subsequently expanded by Jürgen Habermas ( Communicative Rationality ), among others .

Instead of this static term, Norbert Elias uses the process-oriented term “rationalization”, which in his theory of the civilization process means an increase in “long-term view”, which describes the ability to “calculate” the consequences of one's own actions in advance using more and more links in the causal chain.

More recent developments in the field of action theory are the theory of rational decision , as it developed out of the knowledge program of utilitarianism , classical economics and homo economicus (in contrast to homo sociologicus , which is shaped by role theory ).

psychology

According to CG Jung, values are conveyed through rational functions. He distinguishes two rational functions from two irrational ones. Rational functions are thinking and feeling , irrational functions are intuition and feeling . The decisive criterion for the assignment to the group of rational functions is the evaluation of internal psychological facts, see e.g. B. Self-awareness , personalization etc. The result of this rational evaluation is the so-called → attitude . Intelligence does not correlate with rationality.

literature

Ulrich Arnswald, Hans-Peter Schütt (ed.): Rationality and irrationality in the sciences. VS Verlag für Sozialwiss., Wiesbaden 2011, ISBN 978-3-531-18269-8 .
Ulf Bohmann, Benjamin Bunk, Elisabeth Johanna Koehn, Sascha Wegner, Pauka Wojcik (eds.): The promise of rationality. Visions and revisions of the Enlightenment. Wilhelm Fink, Paderborn 2012, ISBN 978-3-7705-5321-1 .
Franz-Josef Bormann, Christian Schröer (Hrsg.): Weighing reason: practical rationality. From a historical, systematic and religious-philosophical perspective. De Gruyter, Berlin 2004, ISBN 978-3-11-017517-2 .
Lorraine Daston : Miracles, Evidence, and Facts: On the History of Rationality. 2nd Edition. Fischer, Frankfurt 2001, ISBN 978-3-596-14763-2 .
Andreas Dorschel , Matthias Kettner: System Rationality? In: Karl-Otto Apel, Matthias Kettner (ed.): The one reason and the many rationalities. Suhrkamp, Frankfurt am Main 1996, pp. 349-372. Criticism of Niklas Luhmann's concept of rationality.
Franz Eisenführ, Martin Weber: Rational decision-making. 4th edition. Springer, Berlin 2003, ISBN 978-3-540-44023-9 .
Jon Elster : Subversion of Rationality (Theory and Society). Campus, Frankfurt 1986, ISBN 978-3-593-33610-7 .
Karen Gloy (Ed.): Types of Rationality. Alber, Freiburg / Munich 1999, ISBN 978-3-495-47960-5 .
Stefan Gosepath: Enlightened self-interest: A theory of theoretical and practical rationality. Suhrkamp, Frankfurt 1992, ISBN 978-3-518-58125-4 .
Stefan Gosepath (Ed.): Motives, reasons, purposes. Theories of practical rationality. Fischer, Frankfurt am Main 1999, ISBN 978-3-596-13223-2 .
Nicole Karafyllis, Jan Schmidt (ed.): Approaches to the rationality of the future. Metzler, Stuttgart 2002, ISBN 978-3-476-45307-5 . ( Review on H-Soz-u-Kult )
Chongki Kim: Aesthetic common sense and aesthetic rationality. Dissertation (PDF; 1.1 MB) Berlin 2007.
Petra Kolmer, Harald Korten (ed.): Limits of reason. Philosophical contributions to the debate on rationality. Festschrift for Hans Michael Baumgartner , Alber, Freiburg / Munich 1994, ISBN 3-495-47756-X .
Hans Lenk , Helmut Spinner : Overview of types of rationality, concepts of rationality and theories of rationality. In: H. Stachowiak (Ed.): Handbook of pragmatic thinking. Hamburg 1989, pp. 1-31.

Nicholas Rescher : Rationality. A Philosophical Inquiry into the Nature and Grounds of Reason. Königshausen & Neumann, Würzburg 1992, ISBN 978-3-88479-781-5 .

Herbert Schnädelbach (Ed.): Rationality. Philosophical contributions. Suhrkamp, Frankfurt am Main 1984, ISBN 978-3-518-28049-2 .

Silvio Vietta : The world society. How western rationality conquered and changed the world. Baden-Baden 2016, ISBN 978-3-8487-2998-2 .

Silvio Vietta: Rationality - A World History. European cultural history and globalization. Fink, Munich 2012, ISBN 978-3-7705-5331-0 .

Axel Wüstehube (Ed.): Pragmatic theories of rationality. Studies in Pragmatism, Idealism, and Philosophy of Mind. Königshausen & Neumann, Würzburg 1999, ISBN 978-3-88479-990-1 .

Web links

Wiktionary: rational - explanations of meanings, word origins, synonyms, translations

philosophy

Kurt Bayertz : Die Rationalität des Amoralismus , Preprints and Working Papers of the Center for Advanced Study in Bioethics, Münster 2014
David J. Furley : Rationality among the Greeks and Romans in the Dictionary of the History of Ideas
Stefan Gosepath: A Uniform Concept of Rationality , in: Protosociology, Vol. 6, 1994, Rationality I, pp. 104–119, ISSN 0940-4147 (online version)
Gotthard Günther : Broken Rationality (PDF; 256 kB)
Helmut Heit: From Myth to Logos. A change in method? (PDF; 2.3 MB)
Christoph Hubig : Instrumental Reason and Value Rationality (PDF; 9.8 MB)
Andreas Kemmerling : Theory of the mind without reason - considerations for an attempt to prove the concept of rationality as worthless
Johannes Marx / Christine Tiefensee: Rationality and Normativity . Journal for Political Theory, Vol. 6, Issue 1/2015, 19–37
Carl Matheson: Historicist Theories of Rationality. In: Edward N. Zalta (Ed.): Stanford Encyclopedia of Philosophy .
Julian Nida-Rümelin : Reason and Freedom (PDF; 491 kB) (Lecture at the University of Duisburg - Essen), 2007
Hans-Joachim Niemann : Rationality in Ethics: The border posts wobble (critical remarks on an article by Gerhard Schurz ; PDF; 104 kB), in: Ethik und Sozialwissenschaften 6 (1995) Heft 2, pp. 206-208.
Ralph Schumacher: Rationality and Intentionality. Can rationality standards be shown a priori as generally binding? (PDF; 46 kB)
Gunnar Skirbekk: Rationality - universal and plural? A Narrative (PDF; 180 kB)
Wolfgang Spohn: How can the theory of rationality be normative and empirical at the same time? ,
Richard Samuels, Stephen Stich , Luc Faucher: Reason and Rationality
Marcus Willaschek: Rational Postulates. About Kant's thesis of the primacy of pure practical reason

Economy

Cornelius Castoriadis : The "Rationality" of Capitalism (PDF; 84 kB)
Justus Haucap: Restricted rationality in the competitive economy (PDF; 360 kB)
Julian Nida-Rümelin: Economic Rationality and Practical Reason (PDF; 2.5 MB), in: Martin Hollis and Wilhelm Vossenkuhl : Moral Decision and Rational Choice . Oldenburg, Munich 1992, 131-152

sociology

Klaus Bendel: Functional Differentiation and Social Rationality . On Niklas Luhman's conception of the relationship between self-reference and coordination in modern societies, in: Zeitschrift für Soziologie, Vol. 22, Issue 4, August 1993, pp. 261–278.

T. Bonacker: Social Rationality and the Realization of Discursive Conflict Resolution: Jürgen Habermas

Achim Brosziewski: Rationality, Uncertainty and Organization - On a revision of organizational sociological assumptions in professional sociology (PDF; 190 kB)

Hartmut Esser : The rationality of everyday action . A reconstruction of Alfred Schütz's theory of action

Otto Keck : Rational communicative action in international relations . Is it possible to combine rational choice theory and Habermas' theory of communicative action ?, in: Journal for International Relations. 2nd year (1995) issue 1, 5-48

Clemens Kroneberg: The definition of the situation and the variable rationality of the actors , Journal for Sociology, vol. 34, issue 5, October 2005, pp. 344–363.

Rudolf Stichweh: Rationalität bei Parsons , in: Zeitschrift für Soziologie, Vol. 9, Issue 1, January 1980, pp. 54–78.

Max Weber : Formal and material rationality of the economy (from: Economy and Society , 1922) (Michael Hartmann: Explanation )

Law

Felix Ekardt / Cornelia Richter: Ockham, Hobbes and the birth of secular normativity. (PDF; 130 kB) On the genesis of secularity, individuality and rationality in law and morality

religion

Karlheinz Ruhstorfer: Spirituality and rationality in the old church and with Ignatius von Loyola (PDF; 1.1 MB), in: Theologie und Glaube 92 (2002), 408-428
Robert Spaemann : Rationality and Belief in God

Individual evidence

↑ For a conceptual analysis cf. for example Stefan Gosepath: A uniform conception of rationality. In: Nicole Karafyllis, Jan Schmidt (Ed.): Approaches to the rationality of the future. Metzler, Stuttgart 2002, pp. 29-52; for goal orientation: p. 43.

↑ Joachim Gerlach: The sentence of sufficient reason: From A. Schopenhauer to H. Kuhlenbeck. In: Würzburger medical history reports 8, 1990, pp. 369–379; here: p. 370 f.

↑ Karl-Otto Apel and Matthias Kettner (eds.): The one reason and the many rationalities. Suhrkamp, Frankfurt 1996.

^ Karl-Heinz Hillmann : Dictionary of Sociology (= Kröner's pocket edition . Volume 410). 4th, revised and expanded edition. Kröner, Stuttgart 1994, ISBN 3-520-41004-4 , Lexikon-Stw. Rationality. P. 718.

↑ Max Horkheimer: On the Critique of Instrumental Reason [ Eclipse of Reason. 1947], Fischer, Frankfurt 1967.

↑ Nicholas Rescher: Rationality. A Philosophical Inquiry into the Nature and Grounds of Reason. Königshausen & Neumann, Würzburg 1992, 152

↑ Max Weber: Wirtschaft und Gesellschaft [1921], 5th edition Mohr Siebeck, Tübingen 1976, 12 (online)

↑ Herbert Schnädelbach: For the rehabilitation of the animal rationale. Lectures and papers, Suhrkamp, Frankfurt 1992, 64-65; see. also the book title by: Stefan Gosepath: Enlightened self-interest. A theory of theoretical and practical rationality, Suhrkamp, Frankfurt 1992

↑ Max Bense : Disobedience of Ideas, Berlin / Cologne 1965, 26

^ Günter Ropohl : Rationality and general systems theory. A way of synthetic rationality, in: Nicole Karafyllis, Jan Schmidt (Hrsg.): Approaches to the rationality of the future. Metzler, Stuttgart 2002, 113-137, 115

↑ Andreas Kemmerling : Theory of Mind Without Reason - Considerations on an attempt to prove the concept of rationality to be worthless ( Memento of June 21, 2013 in the Internet Archive ) (PDF; 2.1 MB), in: HF Fulda / RP Horstmann (ed .), Concepts of Reason in the Modern Age - Stuttgart Hegel Congress 1993, Stuttgart 1994, 704-726

↑ Bernard Gert: The moral rules. A new justification of morality. Suhrkamp, Frankfurt 1983, p. 49

↑ Jan Peter Beckmann : Knowledge, Rationality and Orientation Knowledge. On how to deal with current debates in a consensual manner, in: Ludger Honnefelder, Dieter Sturma (Ed.): Yearbook for Science and Ethics, de Gruyter, Berlin 2009, 5-22, 13

↑ Julian Nida-Rümelin: To Orientate Philosophical Practice: Practical Rationality and Coherence (accessed on March 15, 2017)

↑ Nikolaos Psarros : Rationality and Common Good. Linguistic analytical reflections, in: Nicole Karafyllis, Jan Schmidt (Hrsg.): Approaches to the rationality of the future. Metzler, Stuttgart 2002, 53-72

↑ Wieslaw Sztumski: Why Rationality ?, In: Gerhard Banse, Andrzej Kiepas (ed.): Rationality today - ideas, changes, challenges. Lit, Münster 2002, 61-70, here 64

↑ Wieslaw Sztumski: Why Rationality ?, In: Gerhard Banse, Andrzej Kiepas (ed.): Rationality today - ideas, changes, challenges. Lit, Münster 2002, 61-70, here 67

↑ Wieslaw Sztumski: Why Rationality ?, In: Gerhard Banse, Andrzej Kiepas (ed.): Rationality today - ideas, changes, challenges. Lit, Münster 2002, 61-70, here 69

↑ Hans Lenk: Rationality types, in: Rationality and Science. A lecture series, ed. on behalf of the Center for Philosophical Foundations of Science by G. Pasternack, Bremen 1988, 9-22, taken from Karen Gloy: Vernunft und das Other der Vernunft, Alber, Freiburg / Munich 2001, 28-29