Editing Practical reason

{{Short description|Use of reason to decide how to act}}
In [[philosophy]], '''practical reason''' is the use of [[reason]] to decide how to [[philosophy of action|act]]. It contrasts with theoretical reason, often called [[speculative reason]], the use of reason to decide what to [[Belief|believe]]. For example, agents use practical reason to decide whether to build a [[telescope]], but theoretical reason to decide which of two theories of light and [[optics]] is the best.

==Overview==
Practical reason is understood by most philosophers as determining a plan of action. [[Thomism|Thomistic]] ethics defines the first principle of practical reason as "good is to be done and pursued, and evil is to be avoided."<ref>[http://www.newadvent.org/summa/2094.htm#article2 ''Summa Theologiæ'', I-IIª q. 94 a. 2].</ref> For [[Immanuel Kant|Kant]], practical reason has a law-abiding quality because the [[categorical imperative]] is understood to be binding one to one's duty rather than subjective preferences. [[Utilitarianism|Utilitarians]] tend to see reason as an instrument for the satisfactions of wants and needs.

In classical philosophical terms, it is very important to distinguish three domains of human activity: theoretical reason, which investigates the truth of [[Contingency (philosophy)|contingent]] events as well as [[Logical truth|necessary truths]]; practical reason, which determines whether a prospective course of action is worth pursuing; and productive or technical reason, which attempts to find the best means for a given end. [[Aristotle]] viewed philosophical activity as the highest activity of the human being and gave pride of place to [[metaphysics]] or wisdom. Since [[René Descartes|Descartes]] practical judgment and reasoning have been treated with less respect because of the demand for greater certainty and an infallible method to justify beliefs.

== In argumentation ==

Practical reasoning is basically goal-directed reasoning from an agent's goal, and from some action selected as a means to carry out the goal, to the agent's reasoned decision to carry out the action. The agent can be a person or a technical device, such as a robot or  a software device for multi-agent communications. It is a type of reasoning used all the time in everyday life and all kinds of technology where autonomous reasoning is required. [[Argumentation theory|Argumentation theorist]]s have identified two kinds of practical reasoning: ''[[Instrumental and value rationality|instrumental practical reasoning]]'' that does not explicitly take values into account,<ref>{{cite book|last1=Walton|first1=Douglas |authorlink1=Douglas N. Walton |last2=Reed|first2=Chris|last3=Macagno|first3=Fabrizio|title=Argumentation Schemes|date=2008|publisher=[[Cambridge University Press]]|location=New York|pages=94–95}}</ref> and ''[[Instrumental and value rationality|value-based practical reasoning]]''.<ref name="Atkinson2005">{{cite journal|last1=Atkinson|first1=Katie|last2=Bench-Capon|first2=Trevor|last3=McBurney|first3=Peter|title=A Dialogue Game Protocol for Multi-Agent Argument over Proposals for Action|journal=[[Autonomous Agents and Multi-Agent Systems]]|date=2005|volume=11|issue=2|pages=153–71|doi=10.1007/s10458-005-1166-x|citeseerx=10.1.1.130.8439|s2cid=1824624}}</ref> The following [[argumentation scheme]] for instrumental practical reasoning is given in {{harvtxt|Walton|Reed|Macagno|2008}}. The pronoun ''I'' represents an autonomous agent.

===Argumentation scheme for instrumental practical reasoning===
{|
|-
| MAJOR PREMISE:|| I have a goal G.
|-
| MINOR PREMISE:|| Carrying out this action A is a means to realize G.
|-
| CONCLUSION:|| Therefore, I ought (practically speaking) to carry out this action A.
|}

'''Critical questions'''

:CQ1: What other goals do I have that should be considered that might conflict with G?
:CQ2: What alternative actions to my bringing about A that would also bring about G should be considered?
:CQ3: Among bringing about A and these alternative actions, which is arguably the most efficient?
:CQ4: What grounds are there for arguing that it is practically possible for me to bring about A?
:CQ5: What consequences of my bringing about A should also be taken into account?

It can be seen from CQ5  that argumentation from consequences is closely related to the scheme for practical reasoning.
It has often been disputed in philosophy whether practical reasoning is purely instrumental or whether it needs to be based on values. Argument from values is combined with practical reasoning in the type of argumentation called value-based practical reasoning.<ref name="Atkinson2005"/><ref>{{cite journal|last1=Atkinson|first1=Katie|last2=Bench-Capon|first2=Trevor|last3=McBurney|first3=Peter|title=Computational Representation of Practical Argument|journal=[[Synthese]]|date=2006|volume=152|issue=2|pages=157–206|doi=10.1007/s11229-005-3488-2|citeseerx=10.1.1.127.8521|s2cid=5710585}}</ref><ref>{{cite journal|last1=Macagno|first1=Fabrizio|last2=Walton|first2=Douglas |authorlink2=Douglas N. Walton |title=Persuasive Definitions: Values, Meanings and Implicit Disagreements|journal=Informal Logic|date=2008|volume=28|issue=3|pages=203–28|url=http://ojs.uwindsor.ca/ojs/leddy/index.php/informal_logic/article/viewArticle/594|doi=10.22329/il.v28i3.594|doi-access=free}}</ref> The following [[argumentation scheme]] for value-based practical reasoning is given in {{harvtxt|Atkinson|Bench-Capon|McBurney|2005|pp=2–3}}.

===Argumentation scheme for value-based practical reasoning===

:In the current circumstances R
:we should perform action A
:to achieve New Circumstances S
:which will realize some goal G
:which will promote some value V.

Practical reasoning is used in arguments, but also in explanations used to draw conclusions about an agent's goals, motives or intentions, based on reports of what the agent said or did.

Practical reasoning is centrally important in artificial intelligence, and also vitally important in many other fields such as law, medicine and engineering. It has been known as a distinctive type of argumentation as far back as Aristotle.{{Citation needed|date=January 2017}}

== See also ==
{{Div col|colwidth=20em}}
* [[Action theory (philosophy)]]
* ''[[Critique of Practical Reason]]''
* [[Decisional balance]], or balance-of-considerations reasoning
* {{section link|Humeanism#Practical reason}}
* [[Philosophy of action]]
* [[Phronesis]]
* [[Pure practical reason]]
* [[Rationality]]
* ''[[Rationality and Power]]''
* [[Rhetorical reason]]
* [[Tacit knowledge]]
{{Div col end}}

== References ==
{{reflist}}

== Sources ==
*Elijah Millgram, ed., ''Varieties of Practical Reasoning'', Cambridge, Massachusetts:  MIT Press, 2001.  {{ISBN|0-262-63220-9}}.
*Joseph Raz, ed., ''Practical Reasoning'', Oxford:  Oxford University Press, 1978.  {{ISBN|0-19-875041-2}}.
*Charles Taylor, "Explanation and Practical Reason", in ''Philosophical Arguments'', Cambridge, Massachusetts: Harvard University Press, 1995. {{ISBN|0-674-66476-0}}.

== External links ==
* {{Cite SEP |url-id=practical-reason |title=Practical Reason |first=R. Jay |last=Wallace |date=26 March 2014}}
* {{Cite IEP |url-id=prac-med |title=Medieval Theories of Practical Reason |first=Toner |last=Christopher |date=March 2010}} 
* {{Cite SEP |url-id=practical-reason-med |title=Medieval Theories of Practical Reason |first=Anthony |last=Celano |date=3 December 2014}}
* {{Cite SEP |url-id=practical-reason-action |title=Practical Reason and the Structure of Actions |first=Elijah |last=Millgram |date=11 May 2016}}

{{Philosophy topics}}

[[Category:Reasoning]]
[[Category:Action (philosophy)]]
[[Category:Concepts in epistemology]]
[[Category:Concepts in ethics]]
[[Category:Critical thinking]]
[[Category:Philosophy of logic]]
[[Category:Thought]]