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general::
Also, beyond the shadow of a doubt. Certainly so, undoubtedly so, as in Beyond a doubt this is the best view of the valley. This phrase, along with the earlier without doubt (dating from c. 1300), asserts the truth of some statement. W.S. Gilbert's version, in The Gondoliers (1889), is: "Of that there is no manner of doubt?? no probable, possible shadow of doubtno possible doubt whatever." In this context shadow means "a trace or slight suggestion." Another variant is beyond a reasonable doubt. This phrase is often used in court when the judge instructs the jury that they must be convinced of the accused's guilt or innocence beyond a reasonable doubt; reasonable here means "logical and rational." Also see BEYOND QUESTION; NO DOUBT.
American Heritage Idioms