Editing Rationality (section)

==== 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>