Unreasonable - Etymology and Related Words

Etymology and Related Words

In the English language and other modern European languages, "reason", and related words, represent words which have always been used to translate Latin and classical Greek terms in the sense of their philosophical usage.

• The original Greek term was "λόγος" logos, the root of the modern English word "logic" but also a word which could mean for example "language" or "explanation" or an "account" (of money handled).
• As a philosophical term logos was translated in its non-linguistic senses in Latin as ratio. This was originally not just a translation used for philosophy, but was also commonly a translation for logos in the sense of an account of money.
• French raison is derived directly from Latin, and this is the direct source of the English word "reason".

The earliest major philosophers to publish in English, such as Francis Bacon, Thomas Hobbes, and John Locke also routinely wrote in Latin and French, and compared their terms to Greek, treating the words "logos", "ratio", "raison" and "reason" as inter-changeable. The meaning of the word "reason" in senses such as "human reason" also overlaps to a large extent with "rationality" and the adjective of "reason" in philosophical contexts is normally "rational", rather than "reasoned" or "reasonable". Some philosophers such as Thomas Hobbes, for example, also used the word ratiocination as a synonym for "reasoning".