Ra"tion*al , n. A rational being. Young.
Ra"tion*al (răsh"ŭn*al),
a. [L.
rationalis: cf. F. rationnel. See Ratio, Reason, and cf. Rationale.]
1. Relating
to the reason; not physical; mental.
Moral philosophy was his chiefest end; for the
rational, the natural, and mathematics . . . were but simple pastimes in comparison of the other.
Sir T. North.
2. Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning.
It is our glory and happiness to have a rational nature.
Law. 3. Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man.
4. (Chem.) Expressing the type, structure, relations, and
reactions of a compound; graphic; -- said of formulæ. See under Formula.
Rational horizon.
(Astron.) See Horizon, 2 (b). -- Rational
quantity (Alg.), one that can
be expressed without the use of a radical sign, or in exact parts of unity; -- opposed to irrational or radical quantity.
-- Rational symptom (Med.), one elicited by the statements of the patient himself and not as the result of a physical examination.
Syn. -- Sane; sound; intelligent; reasonable; sensible; wise; discreet; judicious. -- Rational, Reasonable. Rational has reference to reason as a faculty of the mind, and
is opposed to irrational; as, a rational being, a rational state of mind, rational views,
etc. In these cases the speculative reason is more particularly referred
to. Reasonable has reference to the exercise of this faculty for practical purposes, and means, governed or directed by reason; as,
reasonable desires or plans; a reasonable charge; a reasonable prospect of success.
What higher in her society thou find'st
Attractive, human, rational, love still.
Milton.
A law may be reasonable in itself, although a man does not allow it,
or does not
know the reason of the
lawgivers.
Swift.
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