Reason is the capacity of Consciousness applying logic by drawing valid conclusions from new or existing information, with the aim of seeking the truth. It is associated with such characteristically human activities as philosophy, religion, science, language, mathematics, and art, and is normally considered to be a distinguishing ability possessed by humans. Reason is sometimes referred to as rationality.
Reasoning involves using more-or-less rational processes of Thought and cognition to extrapolate from one's existing knowledge to generate new knowledge, and involves the use of one's intellect. The field of logic studies the ways in which humans can use formal reasoning to produce logically valid and true conclusions. Reasoning may be subdivided into Logical form of logical reasoning, such as deductive reasoning, inductive reasoning, and abductive reasoning.
Aristotle drew a distinction between logical discursive reasoning (reason proper), and intuitive reasoning, in which the reasoning process through intuition—however valid—may tend toward the personal and the subjectively opaque. In some social and political settings logical and intuitive modes of reasoning may clash, while in other contexts intuition and formal reason are seen as complementary rather than adversarial. For example, in mathematics, intuition is often necessary for the creative processes involved with arriving at a formal proof, arguably the most difficult of formal reasoning tasks.
Reasoning, like habit or intuition, is one of the ways by which thinking moves from one idea to a related idea. For example, reasoning is the means by which rational individuals understand the significance of sensory information from their environments, or conceptualize abstract dichotomies such as Causality, truth and falsehood, or good and evil. Reasoning, as a part of executive decision making, is also closely identified with the ability to self-consciously change, in terms of , , attitudes, , and , and therefore with the capacity for freedom and self-determination.
and cognitive scientists have attempted to study and explain how people reason, e.g. which cognitive and neural processes are engaged, and how cultural factors affect the inferences that people draw. The field of automated reasoning studies how reasoning may or may not be modeled computationally. Animal psychology considers the question of whether animals other than humans can reason.
The earliest major philosophers to publish in English, such as Francis Bacon, Thomas Hobbes, and John Locke also routinely wrote in Latin and French, and compared their terms to Greek, treating the words "", "ratio", "raison" and "reason" as interchangeable. The meaning of the word "reason" in senses such as "human reason" also overlaps to a large extent with "rationality" and the adjective of "reason" in philosophical contexts is normally "Rationality", rather than "reasoned" or "reasonable". Some philosophers, Hobbes for example, also used the word ratiocination as a synonym for "reasoning".
In contrast to the use of "reason" as an abstract noun, a reason is a consideration that either explains or justifies events, phenomena, or behavior. Reasons justify decisions, reasons support explanations of natural phenomena, and reasons can be given to explain the actions (conduct) of individuals.
The words are connected in this way: using reason, or reasoning, means providing good reasons. For example, when evaluating a moral decision, "morality is, at the very least, the effort to guide one's conduct by reason—that is, doing what there are the best reasons for doing—while giving equal and weight to the interests of all those affected by what one does."
The conclusions to be drawn from the discussions of Aristotle and Plato on this matter are amongst the most debated in the history of philosophy. But teleological accounts such as Aristotle's were highly influential for those who attempt to explain reason in a way that is consistent with monotheism and the immortality and divinity of the human soul. For example, in the Neoplatonism account of Plotinus, the cosmos has one soul, which is the seat of all reason, and the souls of all people are part of this soul. Reason is for Plotinus both the provider of form to material things, and the light which brings people's souls back into line with their source.
The Neoplatonic conception of the rational aspect of the human soul was widely adopted by medieval Islamic philosophers and continues to hold significance in Iranian philosophy. As European intellectual life reemerged from the Dark Ages, the Christian Patristic tradition and the influence of esteemed Islamic scholars like Averroes and Avicenna contributed to the development of the Scholasticism view of reason, which laid the foundation for our modern understanding of this concept.
Among the Scholastics who relied on the classical concept of reason for the development of their doctrines, none were more influential than Saint Thomas Aquinas, who put this concept at the heart of his Natural Law. In this doctrine, Thomas concludes that because humans have reason and because reason is a spark of the divine, every single human life is invaluable, all humans are equal, and every human is born with an intrinsic and permanent set of basic rights. On this foundation, the idea of human rights would later be constructed by Spanish theologians at the School of Salamanca.
Other Scholastics, such as Roger Bacon and Albertus Magnus, following the example of Islamic scholars such as Alhazen, emphasised reason an intrinsic human ability to decode the created order and the structures that underlie our experienced physical reality. This interpretation of reason was instrumental to the development of the scientific method in the early Universities of the high Middle Ages.
In his search for a foundation of all possible knowledge, Descartes decided to throw into doubt all knowledge— except that of the mind itself in the process of thinking:
This eventually became known as epistemological or "subject-centred" reason, because it is based on the knowing subject, who perceives the rest of the world and itself as a set of objects to be studied, and successfully mastered, by applying the knowledge accumulated through such study. Breaking with tradition and with many thinkers after him, Descartes explicitly did not divide the incorporeal soul into parts, such as reason and intellect, describing them instead as one indivisible incorporeal entity.
A contemporary of Descartes, Thomas Hobbes described reason as a broader version of "addition and subtraction" which is not limited to numbers. This understanding of reason is sometimes termed "calculative" reason. Similar to Descartes, Hobbes asserted that "No discourse whatsoever, can end in absolute knowledge of fact, past, or to come" but that "sense and memory" is absolute knowledge.
In the late 17th century through the 18th century, John Locke and David Hume developed Descartes's line of thought still further. Hume took it in an especially skepticism direction, proposing that there could be no possibility of deducing relationships of cause and effect, and therefore no knowledge is based on reasoning alone, even if it seems otherwise.
Hume famously remarked that, "We speak not strictly and philosophically when we talk of the combat of passion and of reason. Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them." Hume also took his definition of reason to unorthodox extremes by arguing, unlike his predecessors, that human reason is not qualitatively different from either simply conceiving individual ideas, or from judgments associating two ideas, and that "reason is nothing but a wonderful and unintelligible instinct in our souls, which carries us along a certain train of ideas, and endows them with particular qualities, according to their particular situations and relations." It followed from this that animals have reason, only much less complex than human reason.
In the 18th century, Immanuel Kant attempted to show that Hume was wrong by demonstrating that a "transcendental" self, or "I", was a necessary condition of all experience. Therefore, suggested Kant, on the basis of such a self, it is in fact possible to reason both about the conditions and limits of human knowledge. And so long as these limits are respected, reason can be the vehicle of morality, justice, aesthetics, theories of knowledge (epistemology), and understanding.
Here, is the self-legislating or self-governing formulation of universal norms, and theory reasoning is the way humans posit universal natural law.
Under practical reason, the moral autonomy or freedom of people depends on their ability, by the proper exercise of that reason, to behave according to laws that are given to them. This contrasted with earlier forms of morality, which depended on religion and interpretation, or on nature, for their substance.
According to Kant, in a free society each individual must be able to pursue their goals however they see fit, as long as their actions conform to principles given by reason. He formulated such a principle, called the "categorical imperative", which would justify an action only if it could be universalized:
In contrast to Hume, Kant insisted that reason itself (German Vernunft]]) could be used to find solutions to metaphysical problems, especially the discovery of the foundations of morality. Kant claimed that these solutions could be found with his "transcendental logic", which unlike normal logic is not just an instrument that can be used indifferently, as it was for Aristotle, but a theoretical science in its own right and the basis of all the others.
According to Jürgen Habermas, the "substantive unity" of reason has dissolved in modern times, such that it can no longer answer the question "How should I live?" Instead, the unity of reason has to be strictly formal, or "procedural". He thus described reason as a group of three autonomous spheres (on the model of Kant's three critiques):
For Habermas, these three spheres are the domain of experts, and therefore need to be mediated with the "lifeworld" by philosophers. In drawing such a picture of reason, Habermas hoped to demonstrate that the substantive unity of reason, which in pre-modern societies had been able to answer questions about the good life, could be made up for by the unity of reason's formalizable procedures.
Some thinkers, e.g. Foucault, believe there are other forms of reason, neglected but essential to modern life, and to our understanding of what it means to live a life according to reason. Others suggest that there is not just one reason or rationality, but multiple possible systems of reason or rationality which may conflict (in which case there is no super-rational system one can appeal to in order to resolve the conflict).
In the last several decades, a number of proposals have been made to "re-orient" this critique of reason, or to recognize the "other voices" or "new departments" of reason:
For example, in opposition to subject-centred reason, Habermas has proposed a model of communicative reason that sees it as an essentially cooperative activity, based on the fact of linguistic intersubjectivity.
Nikolas Kompridis proposed a widely encompassing view of reason as "that ensemble of practices that contributes to the opening and preserving of openness" in human affairs, and a focus on reason's possibilities for social change.
The philosopher Charles Taylor, influenced by the 20th century German philosopher Martin Heidegger, proposed that reason ought to include the faculty of world disclosure, which is tied to the way we make sense of things in everyday life, as a new "department" of reason.
In the essay "What is Enlightenment?", Michel Foucault proposed a critique based on Kant's distinction between "private" and "public" uses of reason:
However, reason and logic can be thought of as distinct—although logic is one important aspect of reason. Author Douglas Hofstadter, in Gödel, Escher, Bach, characterizes the distinction in this way: Logic is done inside a system while reason is done outside the system by such methods as skipping steps, working backward, drawing diagrams, looking at examples, or seeing what happens if you change the rules of the system. Psychologists Mark H. Bickard and Robert L. Campbell argue that "rationality cannot be simply assimilated to logicality"; they note that "human knowledge of logic and logical systems has developed" over time through reasoning, and logical systems "can't construct new logical systems more powerful than themselves", so reasoning and rationality must involve more than a system of logic. Psychologist David Moshman, citing Bickhard and Campbell, argues for a "metacognitive conception of rationality" in which a person's development of reason "involves increasing consciousness and control of logical and other inferences".
Reason is a type of thought, and logic involves the attempt to describe a system of formal rules or norms of appropriate reasoning. The oldest surviving Western writings to explicitly consider and systematically codify the rules by which reason operates, are the works of the Ancient Greece philosopher Aristotle, especially Prior Analytics and Posterior Analytics
Human reason requires more than being able to associate two ideas—even if those two ideas might be described by a reasoning human as a cause and an effect—perceptions of smoke, for example, and memories of fire. For reason to be involved, the association of smoke and the fire would have to be thought through in a way that can be explained, for example as cause and effect. In the explanation of John Locke, for example, reason requires the mental use of a third idea in order to make this comparison by use of syllogism.
More generally, according to Charles Sanders Peirce, reason in the strict sense requires the ability to create and manipulate a system of , as well as indices and icons, the symbols having only a nominal, though habitual, connection to either (for example) smoke or fire. One example of such a system of symbols and signs is language.
The connection of reason to symbolic thinking has been expressed in different ways by philosophers. Thomas Hobbes described the creation of "Markes, or Notes of remembrance" as speech. He used the word speech as an English version of the Greek word so that speech did not need to be communicated. When communicated, such speech becomes language, and the marks or notes or remembrance are called "Signes" by Hobbes. Going further back, although Aristotle is a source of the idea that only humans have reason (), he does mention that animals with imagination, for whom sense perceptions can persist, come closest to having something like reasoning and , and even uses the word "" in one place to describe the distinctions which animals can perceive in such cases.
Terrence Deacon and Merlin Donald, writing about the origin of language, connect reason not only to language, but also mimesis.Mimesis in modern academic writing, starting with Erich Auerbach, is a technical word, which is not necessarily exactly the same in meaning as the original Greek. They describe the ability to create language as part of an internal modeling of reality, and specific to humankind. Other results are consciousness, and imagination or fantasy. Modern proponents of a genetic predisposition to language itself include Noam Chomsky and Steven Pinker.
If reason is symbolic thinking, and peculiarly human, then this implies that humans have a special ability to maintain a clear consciousness of the distinctness of "icons" or images and the real things they represent. Merlin Donald writes:
In classical descriptions, an equivalent description of this mental faculty is , in the philosophy of Plato. This is the ability to perceive whether a perception is an image of something else, related somehow but not the same, and therefore allows humans to perceive that a dream or memory or a reflection in a mirror is not reality as such. What Klein refers to as is the concerned specifically with thinking and mental images, such as those mental symbols, icons, signes, and marks discussed above as definitive of reason. Explaining reason from this direction: human thinking is special in that we often understand visible things as if they were themselves images of our intelligible "objects of thought" as "foundations" ( in Ancient Greek). This thinking () is "...an activity which consists in making the vast and diffuse jungle of the visible world depend on a plurality of more 'precise' ".
Both Merlin Donald and the Socratic authors such as Plato and Aristotle emphasize the importance of , often translated as imitation or representation. Donald writes:
Donald, like Plato (and Aristotle, especially in On Memory), emphasizes the peculiarity in humans of voluntary initiation of a search through one's mental world. The ancient Greek , normally translated as "recollection" was opposed to or "memory". Memory, shared with some animals, requires a consciousness not only of what happened in the past, but also that something happened in the past, which is in other words a kind of "...but nothing except man is able to recollect." Recollection is a deliberate effort to search for and recapture something once known. Klein writes that, "To become aware of our having forgotten something means to begin recollecting." Donald calls the same thing autocueing, which he explains as follows: "Mimetic acts are reproducible on the basis of internal, self-generated cues. This permits voluntary recall of mimetic representations, without the aid of external cues—probably the earliest form of representational thinking."
In a celebrated paper, the fantasy author and philologist J.R.R. Tolkien wrote in his essay "On Fairy Stories" that the terms "fantasy" and "enchantment" are connected to not only "the satisfaction of certain primordial human desires" but also "the origin of language and of the mind".
Inductive reasoning contrasts with deductive reasoning in that, even in the strongest cases of inductive reasoning, the truth of the premises does not guarantee the truth of the conclusion. Instead, the conclusion of an inductive argument follows with some degree of probability. For this reason also, the conclusion of an inductive argument contains more information than is already contained in the premises. Thus, this method of reasoning is ampliative.
A classic example of inductive reasoning comes from the empiricist David Hume:
Analogical reasoning is a weaker form of inductive reasoning from a single example, because inductive reasoning typically uses a large number of examples to reason from the particular to the general. Analogical reasoning often leads to wrong conclusions. For example:
Formal fallacies occur when there is a problem with the form, or structure, of the argument. The word "formal" refers to this link to the form of the argument. An argument that contains a formal fallacy will always be invalid.
An informal fallacy is an error in reasoning that occurs due to a problem with the content, rather than the form or structure, of the argument.
This leads to the question of what types of first principles, or starting points of reasoning, are available for someone seeking to come to true conclusions. In Greek, "first principles" are , "starting points", and the faculty used to perceive them is sometimes referred to in Aristotle and Plato as which was close in meaning to awareness or consciousness.
Empiricism (sometimes associated with AristotleHowever, the empiricism of Aristotle must certainly be doubted. For example in Metaphysics 1009b, cited above, he criticizes people who think knowledge might not be possible because, "They say that the impression given through sense-perception is necessarily true; for it is on these grounds that both Empedocles and Democritus and practically all the rest have become obsessed by such opinions as these." but more correctly associated with Great Britain philosophers such as John Locke and David Hume, as well as their ancient equivalents such as Democritus) asserts that sensory impressions are the only available starting points for reasoning and attempting to attain truth. This approach always leads to the controversial conclusion that absolute knowledge is not attainable. Idealism, (associated with Plato and his school), claims that there is a "higher" reality, within which certain people can directly discover truth without needing to rely only upon the senses, and that this higher reality is therefore the primary source of truth.
Philosophers such as Plato, Aristotle, Al-Farabi, Avicenna, Averroes, Maimonides, Aquinas, and Hegel argued that reason must be fixed and discoverable—perhaps by dialectic, analysis, or study. Religious philosophers such as Thomas Aquinas and Étienne Gilson attempted to show that reason and revelation are compatible. According to Hegel, "...the only thought which Philosophy brings with it to the contemplation of History, is the simple conception of reason; that reason is the Sovereign of the World; that the history of the world, therefore, presents us with a rational process."
Since the 17th century , reason has often been taken to be a subjectivity, or rather the unaided ability (pure reason) to form concepts. For Descartes, Spinoza, and Leibniz, this was associated with mathematics. Immanuel Kant attempted to show that pure reason could form concepts (time and space) that are the conditions of experience. Kant made his argument in opposition to Hume, who denied that reason had any role to play in experience.
Reason has been seen as cold, an "enemy of mystery and ambiguity", a slave, or judge, of the passions, notably in the work of David Hume. More recently, Freud wrote, “It seems as though the activity of the other agencies of the mind is able only to modify the pleasure principle but not to nullify it; and it remains a question of the greatest theoretical importance, and one that has not yet been answered, when and how it is ever possible for the pleasure principle to be overcome.”
Reasoning that claims the object of a desire is demanded by logic alone is called rationalization.
Rousseau first proposed, in his second Discourse, that reason and political life is not natural and is possibly harmful to mankind. He asked what really can be said about what is natural to mankind. What, other than reason and civil society, "best suits his constitution"? Rousseau saw "two principles prior to reason" in human nature. First we hold an intense interest in our own well-being. Secondly we object to the suffering or death of any sentient being, especially one like ourselves. These two passions lead us to desire more than we could achieve. We become dependent upon each other, and on relationships of authority and obedience. This effectively puts the human race into slavery. Rousseau says that he almost dares to assert that nature does not destine men to be healthy. According to Richard Velkley, "Rousseau outlines certain programs of rational self-correction, most notably the political legislation of the Contrat Social and the moral education in . All the same, Rousseau understands such corrections to be only ameliorations of an essentially unsatisfactory condition, that of socially and intellectually corrupted humanity."
This quandary presented by Rousseau led to Immanuel Kant's new way of justifying reason as freedom to create good and evil. These therefore are not to be blamed on nature or God. In various ways, German Idealism after Kant, and major later figures such Nietzsche, Bergson, Husserl, Max Scheler, and Heidegger, remain preoccupied with problems coming from the metaphysical demands or urges of reason. Rousseau and these later writers also exerted a large influence on art and politics. Many writers (such as Nikos Kazantzakis) extol passion and disparage reason. In politics modern nationalism comes from Rousseau's argument that rationalist cosmopolitanism brings man ever further from his natural state.
In Descartes' Error, Antonio Damasio presents the "Somatic Marker Hypothesis" which states that emotions guide behavior and decision-making. Damasio argues that these somatic markers (known collectively as "gut feelings") are "intuitive signals" that direct our decision making processes in a certain way that cannot be solved with rationality alone. Damasio further argues that rationality requires emotional input in order to function.
Religious adherents sometimes respond by arguing that faith and reason can be reconciled, or have different non-overlapping domains, or that critics engage in a similar kind of irrationalism:
Some commentators have claimed that Western culture can be almost defined by its serious testing of the limits of tension between "unaided" reason and faith in "revelation" truths—figuratively summarized as Athens and Jerusalem, respectively. Leo Strauss spoke of a "Greater Western world" that included all areas under the influence of the tension between Greek rationalism and Abrahamic revelation, including the Muslim lands. He was particularly influenced by the Muslim philosopher Farabi. To consider to what extent Eastern philosophy might have partaken of these important tensions, Strauss thought it best to consider whether dharma or tao may be equivalent to Nature ( in Greek). According to Strauss the beginning of philosophy involved the "discovery or invention of nature" and the "pre-philosophical equivalent of nature" was supplied by "such notions as 'custom' or 'ways, which appear to be really universal in all times and places. The philosophical concept of nature or natures as a way of understanding (first principles of knowledge) brought about a peculiar tension between reasoning on the one hand, and tradition or faith on the other.
Assessing how well someone engages in reasoning is the project of determining the extent to which the person is Rationality or acts rationally. It is a key research question in the psychology of reasoning and cognitive science of reasoning. Rationality is often divided into its respective theoretical and practical counterparts.
If human nature is fixed in this way, we can define what type of community is always best for people. This argument has remained a central argument in all political, ethical, and moral thinking since then, and has become especially controversial since firstly Rousseau's Second Discourse, and secondly, the Theory of Evolution. Already in Aristotle there was an awareness that the had not always existed and had to be invented or developed by humans themselves. The household came first, and the first villages and cities were just extensions of that, with the first cities being run as if they were still families with Kings acting like fathers.
Rousseau in his Second Discourse finally took the shocking step of claiming that this traditional account has things in reverse: with reason, language, and rationally organized communities all having developed over a long period of time merely as a result of the fact that some habits of cooperation were found to solve certain types of problems, and that once such cooperation became more important, it forced people to develop increasingly complex cooperation—often only to defend themselves from each other.
In other words, according to Rousseau, reason, language, and rational community did not arise because of any conscious decision or plan by humans or gods, nor because of any pre-existing human nature. As a result, he claimed, living together in rationally organized communities like modern humans is a development with many negative aspects compared to the original state of man as an ape. If anything is specifically human in this theory, it is the flexibility and adaptability of humans. This view of the animal origins of distinctive human characteristics later received support from Charles Darwin's Theory of Evolution.
The two competing theories concerning the origins of reason are relevant to political and ethical thought because, according to the Aristotelian theory, a best way of living together exists independently of historical circumstances. According to Rousseau, we should even doubt that reason, language, and politics are a good thing, as opposed to being simply the best option given the particular course of events that led to today. Rousseau's theory, that human nature is malleable rather than fixed, is often taken to imply (for example by Karl Marx) a wider range of possible ways of living together than traditionally known.
However, while Rousseau's initial impact encouraged bloody revolutions against traditional politics, including both the French Revolution and the Russian Revolution, his own conclusions about the best forms of community seem to have been remarkably classical, in favor of city-states such as Geneva, and rural living.
Subject-centred reason in early modern philosophy
At this time I admit nothing that is not necessarily true. I am therefore precisely nothing but a thinking thing; that is a mind, or intellect, or understanding, or reason—words of whose meanings I was previously ignorant.
Substantive and formal reason
Act only according to that maxim whereby you can, at the same time, will that it should become a universal law.
The critique of reason
Reason compared to related concepts
Reason compared to logic
/ref> Although the Ancient Greeks had no separate word for logic as distinct from language and reason, Aristotle's neologism "syllogism" () identified logic clearly for the first time as a distinct field of study. When Aristotle referred to "the logical" (), he was referring more broadly to rational thought. See this Perseus search, and compare English translations. and see LSJ dictionary entry for λογικός, section II.2.b.
Reason compared to cause-and-effect thinking, and symbolic thinking
Reason, imagination, mimesis, and memory
A dog might perceive the "meaning" of a fight that was realistically play-acted by humans, but it could not reconstruct the message or distinguish the representation from its referent (a real fight).... Trained apes are able to make this distinction; young children make this distinction early—hence, their effortless distinction between play-acting an event and the event itself
Imitation is found especially in monkeys and apes ...but... Mimesis is fundamentally different from imitation and mimicry in that it involves the invention of intentional representations.... Mimesis is not absolutely tied to external communication.
is a concept, now popular again in academic discussion, that was particularly prevalent in Plato's works. In Aristotle, it is discussed mainly in the ''Poetics''. In Michael Davis's account of the theory of man in that work:
It is the distinctive feature of human action, that whenever we choose what we do, we imagine an action for ourselves as though we were inspecting it from the outside. Intentions are nothing more than imagined actions, internalizings of the external. All action is therefore imitation of action; it is poetic...Davis uses "poetic" in an unusual sense, questioning the contrast in Aristotle between action (, the ) and making (, the ): "Human peculiarly action is imitation of action because thinking is always rethinking. Aristotle can define human beings as at once rational animals, political animals, and imitative animals because in the end the three are the same."
Logical reasoning methods and argumentation
Deductive reasoning
The reasoning in this argument is deductively valid because there is no way in which both premises could be true and the conclusion be false.
Inductive reasoning
Analogical reasoning
Abductive reasoning
Fallacious reasoning
Unreasonable decisions and actions
Traditional problems raised concerning reason
Reason versus truth, and "first principles"
Reason versus emotion or passion
Reason versus faith or tradition
Reason in particular fields of study
Psychology and cognitive science
Behavioral experiments on human reasoning
Developmental studies of children's reasoning
Neuroscience of reasoning
Computer science
Automated reasoning
Meta-reasoning
Evolution of reason
Reason in political philosophy and ethics
Friendship seems to prevail in man and woman according to nature ; for people are by nature pairing more than political , in as much as the household is prior and more necessary than the and making children is more common with the animals. In the other animals, community goes no further than this, but people live together not only for the sake of making children, but also for the things for life; for from the start the functions are divided, and are different for man and woman. Thus they supply each other, putting their own into the common . It is for these reasons that both utility and pleasure seem to be found in this kind of friendship.
See also
Further reading
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