rational horizon

2 definitions found

rational horizon - Collaborative International Dictionary of English v.0.48 :

  Horizon \Ho*ri"zon\, n. [F., fr. L. horizon, fr. Gr. ? (sc. ?)
     the bounding line, horizon, fr. ? to bound, fr. ? boundary,
     limit.]
     1. The line which bounds that part of the earth's surface
        visible to a spectator from a given point; the apparent
        junction of the earth and sky.
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              And when the morning sun shall raise his car
              Above the border of this horizon.     --Shak.
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              All the horizon round
              Invested with bright rays.            --Milton.
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     2. (Astron.)
        (a) A plane passing through the eye of the spectator and
            at right angles to the vertical at a given place; a
            plane tangent to the earth's surface at that place;
            called distinctively the sensible horizon.
        (b) A plane parallel to the sensible horizon of a place,
            and passing through the earth's center; -- called also
            rational horizon or celestial horizon.
        (c) (Naut.) The unbroken line separating sky and water, as
            seen by an eye at a given elevation, no land being
            visible.
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     3. (Geol.) The epoch or time during which a deposit was made.
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              The strata all over the earth, which were formed at
              the same time, are said to belong to the same
              geological horizon.                   --Le Conte.
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     4. (Painting) The chief horizontal line in a picture of any
        sort, which determines in the picture the height of the
        eye of the spectator; in an extended landscape, the
        representation of the natural horizon corresponds with
        this line.
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     5. The limit of a person's range of perception, capabilities,
        or experience; as, children raised in the inner city have
        limited horizons.
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     6. [fig.] A boundary point or line, or a time point, beyond
        which new knowledge or experiences may be found; as, more
        powerful computers are just over the horizon.
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     Apparent horizon. See under Apparent.
  
     Artificial horizon, a level mirror, as the surface of
        mercury in a shallow vessel, or a plane reflector adjusted
        to the true level artificially; -- used chiefly with the
        sextant for observing the double altitude of a celestial
        body.
  
     Celestial horizon. (Astron.) See def. 2, above.
  
     Dip of the horizon (Astron.), the vertical angle between
        the sensible horizon and a line to the visible horizon,
        the latter always being below the former.
  
     Rational horizon, and Sensible horizon. (Astron.) See
        def. 2, above.
  
     Visible horizon. See definitions 1 and 2, above.
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  Rational \Ra"tion*al\ (r[a^]sh"[u^]n*al), a. [L. rationalis: cf.
     F. rationnel. See Ratio, Reason, and cf. Rationale.]
     1. Relating to the reason; not physical; mental.
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              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.
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     2. Having reason, or the faculty of reasoning; endowed with
        reason or understanding; reasoning.
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              It is our glory and happiness to have a rational
              nature.                               --Law.
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     3. Agreeable to reason; not absurd, preposterous,
        extravagant, foolish, fanciful, or the like; wise;
        judicious; as, rational conduct; a rational man.
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     4. (Chem.) Expressing the type, structure, relations, and
        reactions of a compound; graphic; -- said of formulae. See
        under Formula.
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     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.
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     Syn: Sane; sound; intelligent; reasonable; sensible; wise;
          discreet; judicious.
  
     Usage: 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.
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                  What higher in her society thou find'st
                  Attractive, human, rational, love still.
                                                    --Milton.
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                  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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