philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. ...

, practical reason is the use of

reason Reason is the capacity of consciously applying logic by drawing conclusions from new or existing information, with the aim of seeking the truth. It is closely associated with such characteristically human activities as philosophy, science, lang ...

to decide how to act. It contrasts with theoretical reason, often called

speculative reason Speculative reason, sometimes called theoretical reason or pure reason, is theoretical (or logical, deductive) thought, as opposed to practical (active, willing) thought. The distinction between the two goes at least as far back as the ancient G ...

, the use of reason to decide what to follow. For example, agents use practical reason to decide whether to build a

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to obse ...

, but theoretical reason to decide which of two theories of light and

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultrav ...

is the best.

Overview

Practical reason is understood by most philosophers as determining a plan of action. Thomistic ethics defines the first principle of practical reason as "good is to be done and pursued, and evil is to be avoided." For

Kant Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and aest ...

, practical reason has a law-abiding quality because the

categorical imperative The categorical imperative (german: kategorischer Imperativ) is the central philosophical concept in the deontological moral philosophy of Immanuel Kant. Introduced in Kant's 1785 '' Groundwork of the Metaphysic of Morals'', it is a way of eva ...

is understood to be binding one to one's duty rather than subjective preferences. 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 contingent events as well as 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 Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of ...

viewed philosophical activity as the highest activity of the human being and gave pride of place to

metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...

or wisdom. Since 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 theorists have identified two kinds of practical reasoning: '' instrumental practical reasoning'' that does not explicitly take values into account, and '' value-based practical reasoning''. The following

argumentation scheme In argumentation theory, an argumentation scheme or argument scheme is a template that represents a common type of argument used in ordinary conversation. Many different argumentation schemes have been identified. Each one has a name (for example, ...

for instrumental practical reasoning is given in . The pronoun ''I'' represents an autonomous agent.

Argumentation scheme for instrumental practical reasoning

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. The following

for value-based practical reasoning is given in .

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.

References

Sources

*Elijah Millgram, ed., ''Varieties of Practical Reasoning'', Cambridge, Massachusetts: MIT Press, 2001. . *Joseph Raz, ed., ''Practical Reasoning'', Oxford: Oxford University Press, 1978. . *Charles Taylor, "Explanation and Practical Reason," in ''Philosophical Arguments'', Cambridge, Massachusetts: Harvard University Press, 1995. .

External links

* * * * {{Philosophy topics Reasoning Action (philosophy) Concepts in epistemology Concepts in ethics Critical thinking Philosophy of logic Philosophy of mind Thought