Reason

==Reason compared to related concepts==

===Reason compared to logic===
{{See also|Logic}}
The terms ''logic'' or ''logical'' are sometimes used as if they were identical with ''reason'' or ''rational'', or sometimes logic is seen as the most pure or the defining form of reason: "Logic is about reasoning—about going from premises to a conclusion.&nbsp;... When you do logic, you try to clarify reasoning and separate good from bad reasoning."<ref>{{cite book |last=Gensler |first=Harry J. |date=2010 |title=Introduction to Logic |edition=2nd |location=New York |publisher=[[Routledge]] |page=1 |isbn=978-0415996501 |oclc=432990013 |doi=10.4324/9780203855003}}</ref> In modern [[economics]], [[Rational choice theory|rational choice]] is assumed to equate to logically [[Consistency|consistent]] choice.<ref>{{cite book |last=Gächter |first=Simon |date=2013 |chapter=Rationality, social preferences, and strategic decision-making from a behavioral economics perspective |editor1-last=Wittek |editor1-first=Rafael |editor2-last=Snijders |editor2-first=T. A. B. |editor3-last=Nee |editor3-first=Victor |title=The Handbook of Rational Choice Social Research |location=Stanford, CA |publisher=Stanford Social Sciences, an imprint of [[Stanford University Press]] |pages=33–71 (33) |isbn=978-0804784184 |oclc=807769289 |doi=10.1515/9780804785501-004 |s2cid=242795845 |quote=The central assumption of the rational choice approach is that decision-makers have logically consistent goals (whatever they are), and, given these goals, choose the best available option.}}</ref>

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.<ref>{{cite book |last=Hofstadter |first=Douglas R. |author-link=Douglas Hofstadter |date=1999 |orig-year=1979 |title=Gödel, Escher, Bach: An Eternal Golden Braid |edition=20th anniversary |location=New York |publisher=[[Basic Books]] |isbn=0394756827 |oclc=40724766}}</ref> 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 [[Formal system#Logical system|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.<ref>{{cite journal |last1=Bickhard |first1=Mark H. |last2=Campbell |first2=Robert L. |date=July 1996 |title=Developmental aspects of expertise: rationality and generalization |journal=[[Journal of Experimental & Theoretical Artificial Intelligence]] |volume=8 |issue=3–4 |pages=399–417 |doi=10.1080/095281396147393}}</ref><ref name=Moshman2004>{{cite journal |last=Moshman |first=David |date=May 2004 |title=From inference to reasoning: the construction of rationality |journal=Thinking & Reasoning |volume=10 |issue=2 |pages=221–239 |doi=10.1080/13546780442000024 |s2cid=43330718 |url=https://digitalcommons.unl.edu/edpsychpapers/44/}}</ref> 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".<ref name=Moshman2004/><ref>{{cite book |last=Ricco |first=Robert B. |date=2015 |chapter=The development of reasoning |editor-last=Lerner |editor-first=Richard M. |editor-link=Richard M. Lerner |title=Handbook of Child Psychology and Developmental Science |edition=7th |volume=2. Cognitive Processes |location=Hoboken, N.J. |publisher=[[John Wiley & Sons]] |pages=519–570 (534) |isbn=978-1118136850 |oclc=888024689 |doi=10.1002/9781118963418.childpsy213 |quote=Moshman's... theory of the development of deductive reasoning considers changes in metacognition to be the essential story behind the development of deductive (and inductive) reasoning. In his view, reasoning involves explicit conceptual knowledge regarding inference (metalogical knowledge) and metacognitive awareness of, and control over, inference.}}</ref>

Reason is a type of [[thought]], and [[logic]] involves the attempt to describe a system of formal rules or norms of appropriate reasoning.<ref name=Moshman2004/> The oldest surviving writing to explicitly consider the rules by which reason operates are the works of the [[Ancient Greece|Greek]] [[philosopher]] [[Aristotle]], especially ''Prior Analytics'' and ''Posterior Analytics''.<ref>{{cite book|author=Aristotle|title=Complete Works|url=https://archive.org/details/completeworksofa0000aris|url-access=registration|publisher=Princeton University Press|year=1984|volume=1|pages=39–166|isbn=0691099502}}</ref>{{Primary source inline|date=August 2021}} Although the Ancient Greeks had no separate word for logic as distinct from language and reason, Aristotle's [[neologism|newly coined word]] "[[syllogism]]" ({{transliteration|grc|syllogismos}}) identified logic clearly for the first time as a distinct field of study.<ref>{{Citation |last=Smith |first=Robin |title=Aristotle's Logic |date=2017 |url=https://plato.stanford.edu/archives/fall2020/entries/aristotle-logic/ |encyclopedia=The Stanford Encyclopedia of Philosophy |editor-last=Zalta |editor-first=Edward N. |edition=Fall 2020 |publisher=Metaphysics Research Lab, Stanford University |access-date=2022-06-08}}</ref> When Aristotle referred to "the logical" ({{transliteration|grc|hē logikē}}), he was referring more broadly to rational thought.<ref>[https://www.perseus.tufts.edu/hopper/searchresults?all_words=logiko/s&all_words_expand=yes&la=greek See this Perseus search, and compare English translations.] and see [https://www.perseus.tufts.edu/hopper/morph.jsp?l=logikw%3Ds&la=greek&prior=le/getai&d=Perseus:text:1999.01.0049:book=1:section=1217b&i=1#lexicon LSJ dictionary entry for {{lang|grc|λογικός}}, section II.2.b.]</ref>

===Reason compared to cause-and-effect thinking, and symbolic thinking===
{{Main|Causality|Symbols}}
As pointed out by philosophers such as Hobbes, Locke, and Hume, some animals are also clearly capable of a type of "[[association (psychology)|associative thinking]]", even to the extent of associating causes and effects. A dog once kicked, can learn how to recognize the warning signs and avoid being kicked in the future, but this does not mean the dog has reason in any strict sense of the word. It also does not mean that humans acting on the basis of experience or habit are using their reason.{{r|HumeI3xvi}}

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|Locke]], for example, reason requires the mental use of a third idea in order to make this comparison by use of [[syllogism]].<ref>{{cite book|first=John|last=Locke|chapter=Of Reason|year=1689|chapter-url=https://archive.org/details/in.ernet.dli.2015.223061/page/n585/mode/2up|title=An Essay concerning Human Understanding|volume=IV}}</ref>

More generally, according to [[Charles Sanders Peirce]], reason in the strict sense requires the ability to create and manipulate a system of [[symbol]]s, as well as [[Semiotic elements and classes of signs (Peirce)#II. Icon, index, symbol|indices and icons]], the symbols having only a nominal, though habitual, connection to either (for example) smoke or fire.<ref>{{cite book|first=Terrence|last=Deacon|title=The Symbolic Species: The Co-Evolution of Language and the Brain|publisher=W.W. Norton & Company|year=1998|isbn=0393317544}}</ref> 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''.<ref>{{cite book|first=Thomas|last=Hobbes|title=Leviathan|chapter=Of speech|chapter-url=https://archive.org/details/in.ernet.dli.2015.224021/page/n47/mode/1up|year=1651}}</ref> He used the word ''speech'' as an English version of the Greek word {{transliteration|grc|[[logos]]}} so that speech did not need to be communicated.<ref>{{cite book|first=Thomas|last=Hobbes|title=Leviathan|chapter=Of speech|chapter-url=https://archive.org/details/in.ernet.dli.2015.224021/page/n47/mode/1up|year=1651|quote=The Greeks have but one word, {{transliteration|grc|logos}}, for both speech and reason; not that they thought there was no speech without reason, but no reasoning without speech}}</ref> When communicated, such speech becomes language, and the marks or notes or remembrance are called "[[Sign (linguistics)|Signes]]" by Hobbes. Going further back, although Aristotle is a source of the idea that only humans have reason ({{transliteration|grc|logos}}), he does mention that animals with imagination, for whom sense perceptions can persist, come closest to having something like reasoning and {{transliteration|grc|[[nous]]}}, and even uses the word "{{transliteration|grc|logos}}" in one place to describe the distinctions which animals can perceive in such cases.<ref>{{cite book|author=Aristotle|title=[[Posterior Analytics]]|at=II.19}}</ref>

===Reason, imagination, mimesis, and memory===
{{Main|Imagination|Mimesis|Memory|Recollection}}
Reason and [[imagination]] rely on similar [[mental processes]].<ref>{{cite book|author-link=Ruth M.J. Byrne|first=Ruth M.J.|last=Byrne|year=2005|title=The Rational Imagination: How People Create Counterfactual Alternatives to Reality|location=Cambridge, Mass.|publisher=MIT Press}}</ref> Imagination is not only found in humans. Aristotle asserted that {{transliteration|grc|phantasia}} (imagination: that which can hold images or {{transliteration|grc|phantasmata}}) and {{transliteration|grc|phronein}} (a type of thinking that can judge and understand in some sense) also exist in some animals.<ref>{{cite book|author=Aristotle|title=[[De Anima]]|at=III.1–3}}</ref> According to him, both are related to the primary perceptive ability of animals, which gathers the perceptions of different senses and defines the order of the things that are perceived without distinguishing universals, and without deliberation or {{transliteration|grc|logos}}. But this is not yet reason, because human imagination is different.

[[Terrence Deacon]] and [[Merlin Donald]], writing about the [[origin of language]], connect reason not only to [[language]], but also [[mimesis]].<ref>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.</ref> 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]]. In contrast, modern proponents of a genetic predisposition to language itself include [[Noam Chomsky]] and [[Steven Pinker]].{{clarify|reason=Why are these contrasting points of view? From the description here they seem compatible with each other.|date=September 2023}}

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:<ref name=MerlinDonald>{{cite book|first=Merlin|last=Donald|title=Origins of the Modern Mind}}{{ISBN?}}</ref>{{rp|172}}
<blockquote>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</blockquote>

In classical descriptions, an equivalent description of this mental faculty is {{transliteration|grc|eikasia}}, in the philosophy of Plato.<ref name=KleinMeno>{{cite book|first=Jacob|last=Klein|title=A Commentary on the [[Meno]]}}</ref>{{rp|at=Ch.5}} 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 {{transliteration|grc|dianoetic eikasia}} is the {{transliteration|grc|eikasia}} concerned specifically with thinking and mental images, such as those mental symbols, icons, ''{{lang|en-emodeng|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" ({{transliteration|grc|hypothēses}} in Ancient Greek). This thinking ({{transliteration|grc|dianoia}}) is "...an activity which consists in making the vast and diffuse jungle of the visible world depend on a plurality of more 'precise' {{transliteration|grc|noēta}}".{{r|KleinMeno|page=122}}

Both Merlin Donald and the Socratic authors such as Plato and Aristotle emphasize the importance of {{transliteration|grc|mimēsis}}, often translated as ''imitation'' or ''representation''. Donald writes:{{r|MerlinDonald|page=169}}
<blockquote>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.</blockquote>

{{transliteration|grc|Mimēsis}} 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 (Aristotle)|Poetics]]''. In Michael Davis's account of the theory of man in that work:<ref>{{cite book|chapter=Introduction|title=[[Poetics (Aristotle)|Poetics]] of Aristotle|last1=Davis|first1=Michael|first2=Seth|last2=Benardete|pages=xvii, xxviii}}</ref>
<blockquote>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...<ref>Davis uses "poetic" in an unusual sense, questioning the contrast in Aristotle between action ({{transliteration|grc|praxis}}, the {{transliteration|grc|praktikē}}) and making ({{transliteration|grc|poēsis}}, the {{transliteration|grc|poētikē}}): "Human [peculiarly human] 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."</ref></blockquote>

Donald like Plato (and Aristotle, especially in ''[[On Memory|On Memory and Recollection]]''), emphasizes the peculiarity in humans of voluntary initiation of a search through one's mental world. The ancient Greek {{transliteration|grc|anamnēsis}}, normally translated as "recollection" was opposed to {{transliteration|grc|mneme}} or "memory". Memory, shared with some animals,<ref>{{cite book|author=Aristotle|title=[[On Memory]]|at=450a 15–16}}</ref> 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 {{transliteration|grc|eikasia}}{{r|KleinMeno|page=109}} "...but nothing except man is able to recollect."<ref>{{cite book|author=Aristotle|title=[[History of Animals]]|at=I.1.488b.25–26}}</ref> 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."{{r|KleinMeno|page=112}} Donald calls the same thing ''autocueing'', which he explains as follows:{{r|MerlinDonald|page=173}}<ref>{{cite book|last=Donald|first=Merlin|title=A Mind So Rare|pages=140–141}}{{ISBN?}}</ref> "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".{{cite quote|date=September 2023}}

===Logical reasoning methods and argumentation===
{{main|Logical reasoning}}
A subdivision of [[philosophy]] and a variety of reasoning is [[logic]]. The traditional main division made in philosophy is between [[deductive reasoning]] and [[inductive reasoning]]. [[Logic|Formal logic]] has been described as ''the science of deduction''.<ref>{{cite book|last=Jeffrey|first=Richard|year=1991|title=Formal logic: its scope and limits|edition=3rd|location=New York|publisher=McGraw-Hill|page=1}}</ref> The study of inductive reasoning is generally carried out within the field known as [[informal logic]] or [[critical thinking]].

====Deductive reasoning====
{{Main|Deductive reasoning}}
Deduction is a form of reasoning in which a conclusion follows necessarily from the stated premises. A deduction is also the name for the conclusion reached by a deductive reasoning process. A classic example of deductive reasoning is evident in [[syllogism]]s like the following:
{| {{Table}}
! Premise 1
| All humans are mortal.
|-
! Premise 2 
| Socrates is a human.
|-
! Conclusion 
| Socrates is mortal.
|}
The reasoning in this argument is deductively [[Validity (logic)|valid]] because there is no way in which both premises could be true and the conclusion be false.

====Inductive reasoning====
{{Main|Inductive reasoning}}
Induction is a form of inference that produces [[category of being|properties or relations]] about unobserved objects or [[type (metaphysics)|types]] based on [[event (philosophy)|previous observations or experiences]], or that formulates general statements or [[law (principle)|laws]] based on limited observations of recurring [[phenomena]]l patterns.

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]]:
{| {{Table}}
! Premise
| The sun has risen in the east every morning up until now.
|-
! Conclusion 
| The sun will also rise in the east tomorrow.
|}

====Analogical reasoning====
{{Main|Analogical reasoning}}
Analogical reasoning is a form of inductive reasoning from a particular to a particular. It is often used in [[case-based reasoning]], especially legal reasoning.<ref>{{cite book |last=Walton |first=Douglas N. |title=Systematic Approaches to Argument by Analogy |chapter=Argumentation Schemes for Argument from Analogy |author-link=Douglas N. Walton |date=2014 |editor-last=Ribeiro |editor-first=Henrique Jales |series=Argumentation library |volume=25 |location=Cham; New York |publisher=[[Springer Verlag]] |pages=23–40 |isbn=978-3319063331 |oclc=884441074 |doi=10.1007/978-3-319-06334-8_2|chapter-url=https://scholar.uwindsor.ca/crrarpub/15 }}</ref> An example follows:
{| {{Table}}
! Premise 1
| Socrates is human and mortal.
|-
! Premise 2
| Plato is human.
|-
! Conclusion 
| Plato is mortal.
|}

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.<ref>{{cite encyclopedia |last=Henderson |first=Leah |title=The Problem of Induction |encyclopedia= The Stanford Encyclopedia of Philosophy |year=2022 |url=http://plato.stanford.edu/entries/induction-problem/ |publisher=Metaphysics Research Lab, Stanford University }}</ref> Analogical reasoning often leads to wrong conclusions. For example:
{| {{Table}}
! Premise 1
| Socrates is human and male.
|-
! Premise 2
| [[Ada Lovelace]] is human.
|-
! Conclusion 
| Ada Lovelace is male.
|}

====Abductive reasoning====
{{Main|Abductive reasoning}}
Abductive reasoning, or argument to the best explanation, is a form of reasoning that does not fit in either the deductive or inductive categories, since it starts with incomplete set of observations and proceeds with likely possible explanations. The conclusion in an abductive argument does not follow with certainty from its premises and concerns something unobserved. What distinguishes abduction from the other forms of reasoning is an attempt to favour one conclusion above others, by subjective judgement or by attempting to falsify alternative explanations or by demonstrating the likelihood of the favoured conclusion, given a set of more or less disputable assumptions. For example, when a patient displays certain symptoms, there might be various possible causes, but one of these is preferred above others as being more probable.

====Fallacious reasoning====
{{Main|Fallacy|Formal fallacy|Informal fallacy}}
Flawed reasoning in arguments is known as [[fallacy|fallacious reasoning]]. Bad reasoning within arguments can result from either a [[formal fallacy]] or an [[informal fallacy]].

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.