Philosophy is essentially a middle-aged man’s game, though certain philosophers (notably Plato and Kant) have put up their best performances when they were well past middle life. Those of us who are not Platos or Kants are well advised to retire gracefully before they have too obviously lost their grip. Medical science would almost have made the world safe for senility, if physics had not made it unsafe for everybody; and there are far too many old clowns arthritically going through their hoops, to the embarrassment of the spectators:

From X’s eyes the streams of dotage flow,
And Y expires a driveller and a show.

My younger colleagues would have no difficulty in substituting appropriate constants for the variables in these lines. Moreover, though philosophies are never refuted, they rapidly go out of fashion, and the kind of philosophy which I have practised has become antiquated without having yet acquired the interest of a collector’s piece:

New forms arise, and different views engage,
Superfluous lags the veteran on the stage.

So this veteran now definitely makes his last bow as a professional performer, though he may occasionally make a graceful appearance “by request” at a matinee for charity.

C. D. Broad, ‘A Reply to My Critics’, in Paul A. Schilpp (ed.) The Philosophy of C. D. Broad, New York, 1959, pp. 711-830