Reason

v. think, consider logically; support a claim with reasons, justify by giving reasons; argue, claim

n. cause, basis for action; intelligence, sense

In western philosophy, reason has had a twofold history. On the one hand, it has been taken to be objective and so to be fixed and discoverable by dialectic, analysis or study. Such objectivity is the case in the thinking of Plato, Aristotle, Aquinas, Maimonides, al-Farabi and Hegel. In the vision of these thinkers, reason is divine or at least has divine attributes. Such an approach compelled religious philosophers--Aquinas, for example, Gilson more recently--to square reason with revelation, no easy task.
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Noun
1. a rational motive for a belief or action; "the reason that war was declared"; "the grounds for their declaration"
(synonym) ground
(hypernym) rational motive
(hyponym) occasion
(derivation) reason out, conclude
2. an explanation of the cause of some phenomenon; "the reason a steady state was never reached was that the back pressure built up too slowly"
(hypernym) explanation, account
3. the capacity for rational thought or inference or discrimination; "we are told that man is endowed with reason and capable of distinguishing good from evil"
(synonym) understanding, intellect
(hypernym) faculty, mental faculty, module
4. the state of having good sense and sound judgment; "his rationality may have been impaired"; "he had to rely less on reason than on rousing their emotions"
(synonym) rationality, reasonableness
(hypernym) sanity, saneness
(derivation) argue
5. a justification for something existing or happening; "he had no cause to complain"; "they had good reason to rejoice"
(synonym) cause, grounds
(hypernym) justification
6. a fact that logically justifies some premise or conclusion; "there is reason to believe he is lying"
(hypernym) fact
(hyponym) indication
Verb
1. decide by reasoning; draw or come to a conclusion; "We reasoned that it was cheaper to rent than to buy a house"
(synonym) reason out, conclude
(hypernym) think, cogitate, cerebrate
(hyponym) induce
(derivation) rationality, reasonableness
2. present reasons and arguments
(synonym) argue
(hypernym) present, represent, lay out
(hyponym) re-argue
(derivation) rationality, reasonableness
3. think logically; "The children must learn to reason"
(hypernym) think, cogitate, cerebrate
(hyponym) rationalize away, rationalise away
(derivation) understanding, intellect

(v. t.)
To support with reasons, as a request.
  

(v. t.)
To persuade by reasoning or argument; as, to reason one into a belief; to reason one out of his plan.
  

(v. t.)
To overcome or conquer by adducing reasons; -- with down; as, to reason down a passion.
  

(v. t.)
To find by logical processes; to explain or justify by reason or argument; -- usually with out; as, to reason out the causes of the librations of the moon.
  

(v. t.)
To arrange and present the reasons for or against; to examine or discuss by arguments; to debate or discuss; as, I reasoned the matter with my friend.
  

(n.)
To exercise the rational faculty; to deduce inferences from premises; to perform the process of deduction or of induction; to ratiocinate; to reach conclusions by a systematic comparison of facts.
  

(n.)
To converse; to compare opinions.
  

(n.)
The faculty or capacity of the human mind by which it is distinguished from the intelligence of the inferior animals; the higher as distinguished from the lower cognitive faculties, sense, imagination, and memory, and in contrast to the feelings and desires. Reason comprises conception, judgment, reasoning, and the intuitional faculty. Specifically, it is the intuitional faculty, or the faculty of first truths, as distinguished from the understanding, which is called the discursive or ratiocinative faculty.
  

(n.)
Ratio; proportion.
  

(n.)
Hence: To carry on a process of deduction or of induction, in order to convince or to confute; to formulate and set forth propositions and the inferences from them; to argue.
  

(n.)
Due exercise of the reasoning faculty; accordance with, or that which is accordant with and ratified by, the mind rightly exercised; right intellectual judgment; clear and fair deductions from true principles; that which is dictated or supported by the common sense of mankind; right conduct; right; propriety; justice.
  

(n.)
A thought or a consideration offered in support of a determination or an opinion; a just ground for a conclusion or an action; that which is offered or accepted as an explanation; the efficient cause of an occurrence or a phenomenon; a motive for an action or a determination; proof, more or less decisive, for an opinion or a conclusion; principle; efficient cause; final cause; ground of argument.
  

Reason The wisdom which ensues from the union of buddhi with manas, as contrasted with the higher immanent wisdom of atma-buddhi; also the human mind, which finds its place in the union of the higher and lower nature through the mediating fourth principle or kama, which itself works through what the Qabbalists call nephesh or the Latins the anima. Again, in some European philosophers, the characteristics of the Logos, which is stated to be cosmic mind or the Third Logos.
In Greek mythology Prometheus is represented as endowing man with reason and the use of the mental faculties, which corresponds to the descent of the manasaputras during the third root-race. In present mankind reason is a quality of manas, and its presence is the chief characteristic distinction between man and animal.