Editing Rationality (section)

=== Theoretical and practical ===
The most influential distinction contrasts theoretical or epistemic rationality with practical rationality. Its theoretical side concerns the rationality of [[belief]]s: whether it is rational to hold a given belief and how certain one should be about it. Practical rationality, on the other hand, is about the rationality of [[Action (philosophy)|actions]], [[intention]]s, and [[Choice|decisions]].<ref name="Mele2004a"/><ref name="Harman2013"/><ref name="Knauff2021a"/><ref name="Kolb2008"/> This corresponds to the distinction between theoretical reasoning and practical reasoning: theoretical reasoning tries to assess whether the agent should change their beliefs while practical reasoning tries to assess whether the agent should change their plans and intentions.<ref name="Harman2013"/><ref name="Knauff2021a"/><ref name="Kolb2008"/>

==== Theoretical ====
Theoretical rationality concerns the rationality of cognitive mental states, in particular, of beliefs.<ref name="Mele2004a"/><ref name="Audi2004"/> It is common to distinguish between two factors. The first factor is about the fact that good reasons are necessary for a belief to be rational. This is usually understood in terms of evidence provided by the so-called [[sources of knowledge]], i.e. faculties like [[perception]], [[introspection]], and [[memory]]. In this regard, it is often argued that to be rational, the believer has to respond to the impressions or reasons presented by these sources. For example, the visual impression of the sunlight on a tree makes it rational to believe that the sun is shining.<ref name="Kolb2008"/><ref name="Mele2004a"/><ref name="Audi2004"/> In this regard, it may also be relevant whether the formed belief is involuntary and implicit 

The second factor pertains to the norms and procedures of rationality that govern how agents should form beliefs based on this evidence. These norms include the [[rules of inference]] discussed in regular [[logic]] as well as other norms of coherence between mental states.<ref name="Mele2004a"/><ref name="Audi2004"/> In the case of rules of inference, the premises of a [[Validity (logic)|valid]] argument offer support to the conclusion and make therefore the belief in the conclusion rational.<ref name="Kolb2008"/> The support offered by the premises can either be [[Deductive reasoning|deductive]] or [[Defeasible reasoning|non-deductive]].<ref name="Hintikka2006"/><ref>{{cite journal |last1=Backmann |first1=Marius |title=Varieties of Justification—How (Not) to Solve the Problem of Induction |journal=Acta Analytica |date=1 June 2019 |volume=34 |issue=2 |pages=235–255 |doi=10.1007/s12136-018-0371-6 |s2cid=125767384 |language=en |issn=1874-6349|doi-access=free }}</ref> In both cases, believing in the premises of an argument makes it rational to also believe in its conclusion. The difference between the two is given by how the premises support the conclusion. For deductive reasoning, the premises offer the strongest possible support: it is impossible for the conclusion to be false if the premises are true. The premises of non-deductive arguments also offer support for their conclusion. But this support is not absolute: the truth of the premises does not guarantee the truth of the conclusion. Instead, the premises make it more likely that the conclusion is true. In this case, it is usually demanded that the non-deductive support is sufficiently strong if the belief in the conclusion is to be rational.<ref name="Knauff2021a"/><ref name="Kolb2008"/><ref name="Hintikka2006"/> 

An important form of theoretical irrationality is motivationally biased belief, sometimes referred to as [[wishful thinking]]. In this case, beliefs are formed based on one's desires or what is pleasing to imagine without proper evidential support.<ref name="Mele2004a"/><ref name="Mele2004b"/> Faulty reasoning in the form of [[Formal fallacy|formal]] and [[informal fallacies]] is another cause of theoretical irrationality.<ref>{{cite web |last1=Dowden |first1=Bradley |title=Fallacies |url=https://iep.utm.edu/fallacy/ |website=Internet Encyclopedia of Philosophy |access-date=19 March 2021 |archive-date=29 April 2010 |archive-url=https://web.archive.org/web/20100429214410/https://iep.utm.edu/fallacy/ |url-status=live }}</ref>

==== Practical ====
All forms of practical rationality are concerned with how we act. It pertains both to [[Action (philosophy)|actions]] directly as well as to mental states and events preceding actions, like [[intention]]s and [[Choice|decisions]]. There are various aspects of practical rationality, such as how to pick a goal to follow and how to choose the means for reaching this goal. Other issues include the coherence between different intentions as well as between beliefs and intentions.<ref name="Hampton1996"/><ref name="Wallace2020"/><ref name="Moser2006"/>

Some theorists define the rationality of actions in terms of beliefs and desires. In this view, an action to bring about a certain goal is rational if the agent has the desire to bring about this goal and the belief that their action will realize it. A stronger version of this view requires that the responsible beliefs and desires are rational themselves.<ref name="Knauff2021b"/> A very influential conception of the rationality of decisions comes from [[decision theory]]. In decisions, the agent is presented with a set of possible courses of action and has to choose one among them. Decision theory holds that the agent should choose the alternative that has the highest [[expected value]].<ref name="Hampton1996"/> Practical rationality includes the field of actions but not of behavior in general. The difference between the two is that actions are intentional behavior, i.e. they are performed for a purpose and guided by it. In this regard, intentional behavior like driving a car is either rational or irrational while non-intentional behavior like sneezing is outside the domain of rationality.<ref name="Knauff2021b"/><ref name="Wilson2002"/><ref>{{cite journal |last1=Mele |first1=Alfred R. |last2=Moser |first2=Paul K. |title=Intentional Action |journal=Noûs |date=1994 |volume=28 |issue=1 |pages=39–68 |doi=10.2307/2215919 |jstor=2215919 |url=https://www.jstor.org/stable/2215919 |issn=0029-4624 |access-date=2022-08-14 |archive-date=2022-08-14 |archive-url=https://web.archive.org/web/20220814154359/https://www.jstor.org/stable/2215919 |url-status=live }}</ref>

For various other practical phenomena, there is no clear consensus on whether they belong to this domain or not. For example, concerning the rationality of desires, two important theories are proceduralism and substantivism. According to proceduralism, there is an important distinction between [[Desire#Intrinsic and instrumental|instrumental and noninstrumental desires]]. A desire is instrumental if its fulfillment serves as a means to the fulfillment of another desire.<ref name="Brad2004"/><ref name="Harman2013"/><ref name="Knauff2021b"/> For example, Jack is sick and wants to take medicine to get healthy again. In this case, the desire to take the medicine is instrumental since it only serves as a means to Jack's noninstrumental desire to get healthy. Both proceduralism and substantivism usually agree that a person can be irrational if they lack an instrumental desire despite having the corresponding noninstrumental desire and being aware that it acts as a means. Proceduralists hold that this is the only way a desire can be irrational. Substantivists, on the other hand, allow that noninstrumental desires may also be irrational. In this regard, a substantivist could claim that it would be irrational for Jack to lack his noninstrumental desire to be healthy.<ref name="Mele2004a"/><ref name="Brad2004"/><ref name="Knauff2021b"/> Similar debates focus on the rationality of [[emotion]]s.<ref name="Knauff2021b"/>

==== Relation between the two ====
Theoretical and practical rationality are often discussed separately and there are many differences between them. In some cases, they even conflict with each other. However, there are also various ways in which they overlap and depend on each other.<ref name="Hampton1996"/><ref name="Knauff2021b"/>

It is sometimes claimed that theoretical rationality aims at truth while practical rationality aims at [[The good|goodness]].<ref name="Hampton1996"/> According to [[John Searle]], the difference can be expressed in terms of "[[direction of fit]]".<ref name="Knauff2021b"/><ref>{{cite journal |last1=Douglass |first1=Curran F. |title=Rationality in Action. By John Searle. Cambridge: MIT Press, 2001. 303 pages, ISBN 0-262-19463-5. Hardback $35.00. |journal=Auslegung: A Journal of Philosophy |date=1 June 2003 |doi=10.17161/AJP.1808.9520|doi-access=free }}</ref><ref>{{cite journal |last1=Kissine |first1=Mikhail |title=Direction of Fit |journal=Logique et Analyse |date=2007 |volume=50 |issue=198 |pages=113–128 |jstor=44084854 |url=https://www.jstor.org/stable/44084854 |issn=0024-5836 |access-date=2022-08-14 |archive-date=2022-08-14 |archive-url=https://web.archive.org/web/20220814154017/https://www.jstor.org/stable/44084854 |url-status=live }}</ref> On this view, theoretical rationality is about how the mind corresponds to the world by representing it. Practical rationality, on the other hand, is about how the world corresponds to the ideal set up by the mind and how it should be changed.<ref name="Knauff2021b"/><ref name="Mele2004a"/><ref name="Harman2004"/><ref name="Moser2006"/> Another difference is that arbitrary choices are sometimes needed for practical rationality. For example, there may be two equally good routes available to reach a goal. On the practical level, one has to choose one of them if one wants to reach the goal. It would even be practically irrational to resist this arbitrary choice, as exemplified by [[Buridan's ass]].<ref name="Harman2013"/><ref>{{cite journal |last1=Chislenko |first1=Eugene |title=A Solution for Buridan's Ass |journal=Ethics |date=2016 |volume=126 |issue=2 |pages=283–310 |doi=10.1086/683537 |s2cid=147175535 |url=https://philpapers.org/rec/CHIASF-2 |access-date=2022-08-14 |archive-date=2022-08-14 |archive-url=https://web.archive.org/web/20220814154359/https://philpapers.org/rec/CHIASF-2 |url-status=live }}</ref> But on the theoretical level, one does not have to form a belief about which route was taken upon hearing that someone reached the goal. In this case, the arbitrary choice for one belief rather than the other would be theoretically irrational. Instead, the agent should suspend their belief either way if they lack sufficient reasons. Another difference is that practical rationality is guided by specific goals and desires, in contrast to theoretical rationality. So it is practically rational to take medicine if one has the desire to cure a sickness. But it is theoretically irrational to adopt the belief that one is healthy just because one desires this. This is a form of [[wishful thinking]].<ref name="Harman2013"/>

In some cases, the demands of practical and theoretical rationality conflict with each other. For example, the practical reason of [[loyalty]] to one's child may demand the belief that they are innocent while the evidence linking them to the crime may demand a belief in their guilt on the theoretical level.<ref name="Harman2013"/><ref name="Harman2004"/>

But the two domains also overlap in certain ways. For example, the norm of rationality known as [[enkrateia|enkrasia]] links beliefs and intentions. It states that "rationality requires of you that you intend to F if you believe your reasons require you to F". Failing to fulfill this requirement results in cases of irrationality known as [[akrasia]] or [[weakness of the will]].<ref name="Broome2021"/><ref name="Moser2006"/><ref name="Heinzelmann2022"/><ref name="Mele2004a"/><ref name="Mele2004b"/> Another form of overlap is that the study of the rules governing practical rationality is a theoretical matter.<ref name="Mele2004a"/><ref name="Dreier2004"/> And practical considerations may determine whether to pursue theoretical rationality on a certain issue as well as how much time and resources to invest in the inquiry.<ref name="Harman2004"/><ref name="Mele2004b"/> It is often held that practical rationality presupposes theoretical rationality. This is based on the idea that to decide what should be done, one needs to know what is the case. But one can assess what is the case independently of knowing what should be done. So in this regard, one can study theoretical rationality as a distinct discipline independent of practical rationality but not the other way round.<ref name="Knauff2021b"/> However, this independence is rejected by some forms of doxastic voluntarism. They hold that theoretical rationality can be understood as one type of practical rationality. This is based on the controversial claim that we can decide what to believe. It can take the form of ''epistemic decision theory'', which states that people try to fulfill epistemic aims when deciding what to believe.<ref name="Knauff2021b"/><ref>{{cite journal |last1=Greaves |first1=Hilary |title=Epistemic Decision Theory |journal=Mind |date=2013 |volume=122 |issue=488 |pages=915–952 |doi=10.1093/mind/fzt090 |url=https://philpapers.org/rec/GREEDT |access-date=2022-08-14 |archive-date=2022-08-14 |archive-url=https://web.archive.org/web/20220814154400/https://philpapers.org/rec/GREEDT |url-status=live }}</ref><ref>{{cite book |last1=Konek |first1=Jason |last2=Levinstein |first2=Ben |title=The Foundations of Epistemic Decision Theory |date=2017 |url=https://philpapers.org/rec/KONTFO-2 |access-date=2022-08-14 |archive-date=2022-08-14 |archive-url=https://web.archive.org/web/20220814154400/https://philpapers.org/rec/KONTFO-2 |url-status=live }}</ref> A similar idea is defended by [[Jesús Mosterín]]. He argues that the proper object of rationality is not ''belief'' but ''acceptance''. He understands acceptance as a voluntary and context-dependent decision to affirm a proposition.<ref>{{cite journal |last1=Mosterín |first1=Jesús |title=Acceptance without belief |journal=Manuscrito |date=2002 |volume=25 |issue=2 |pages=313–335 |url=https://periodicos.sbu.unicamp.br/ojs/index.php/manuscrito/article/view/8644540 |access-date=2019-07-13 |archive-date=2019-07-13 |archive-url=https://web.archive.org/web/20190713172627/https://periodicos.sbu.unicamp.br/ojs/index.php/manuscrito/article/view/8644540 |url-status=live }}</ref>