Sir, – Malachi O’Doherty (Opinion and Analysis, September 5th) is wrong to equate maturity with age. Mr O’Doherty should know that one of Ireland’s most celebrated authors, James Joyce, published two of his masterpieces, A Portrait of the Artist as a Young Man and Dubliners, during his early thirties; that Ireland’s most celebrated philosopher, George Berkeley, published his magnum opus, A Treatise Concerning the Principles of Human Knowledge, during his mid-twenties; and that two of Ireland’s most celebrated political activists, Robert Emmet and Michael Collins, had effected their historical accomplishments by their mid-twenties and early thirties, respectively. – Yours, etc,