Ludicrous, incongruent or logically absurd statement, generally unrecognized as such by its author
An Irish bull is a ludicrous, incongruent or logically absurd statement, generally unrecognized as such by its author. The inclusion of the epithet Irish is a late addition.[1]
John Pentland Mahaffy, Provost of Trinity College, Dublin, observed, "an Irish bull is always pregnant", i.e. with truthful meaning.[2]
The "father" of the Irish bull is often said to be Sir Boyle Roche,[3]
who once asked "Why should we put ourselves out of our way to do anything for posterity, for what has posterity ever done for us?".[4] Roche may have been Sheridan's model for Mrs Malaprop.[5]
Origin
The derivation of "bull" in this sense is unclear. It may be related to Old Frenchboul "fraud, deceit, trickery", Icelandicbull "nonsense", Middle Englishbull "falsehood", or the verb bull "befool, mock, cheat".[6]
As the Oxford English Dictionary points out, the epithet "Irish" is a more recent addition, the original word bull for such nonsense having been traced back at least to the early 17th century.[1] By the late 19th century the expression Irish bull was well known, but writers were expressing reservations such as: "But it is a cruel injustice to poor Paddy to speak of the genuine 'bull' as something distinctly Irish, when countless examples of the same kind of blunder, not a whit less startling, are to be found elsewhere." The passage continues, presenting Scottish, English and French specimens in support.[7]