From Gwydion M. Williams
John Healey asks why people speak of the grandfather paradox, involving a person travelling back in time and killing a grandparent, rather than the mother or father paradox (18 December 2010, p 29). Surely it is to minimise the emotional baggage connected with the problem. Real-life cases of someone murdering their grandfather must be much rarer than patricide or matricide.
Old Fletton, Cambridgeshire, UK
