In philosophy, practical reason is the use of reason to decide how to act. This contrasts with theoretical reason (often called speculative reason), which is the use of reason to decide what to 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. Practical reason is understood by most philosophers as determining a plan of action. Thomistic ethics defines the first principle of practical reason as the "good is to be done and pursued, and evil is to be avoided." For 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. 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 viewed philosophical activity as the highest activity of the human being and gave pride of place to metaphysics 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 cognitive research, practical reason is the process of ignoring unproductive possibilities in favor of productive possibilities. It is considered a form of cognitive bias, because it is illogical. An example would be calling all hospitals to look for your missing child, but not checking morgues, as finding his corpse would be 'counter-productive.'
Famous quotes containing the words practical reason, practical and/or reason:
“After all, the practical reason why, when the power is once in the hands of the people, a majority are permitted, and for a long period continue, to rule is not because they are most likely to be in the right, nor because this seems fairest to the minority, but because they are physically the strongest. But a government in which the majority rule in all cases cannot be based on justice, even as far as men understand it.”
—Henry David Thoreau (1817–1862)
“Call them rules or call them limits, good ones, I believe, have this in common: They serve reasonable purposes; they are practical and within a child’s capability; they are consistent; and they are an expression of loving concern.”
—Fred Rogers (20th century)
“That, upon the whole, we may conclude that the Christian religion not only was at first attended with miracles, but even at this day cannot be believed by any reasonable person without one. Mere reason is insufficient to convince us of its veracity: And whoever is moved by Faith to assent to it, is conscious of a continued miracle in his own person, which subverts all the principles of his understanding, and gives him a determination to believe what is most contrary to custom and experience.”
—David Hume (1711–1776)