Brian Parker, of Cross-parks, Dartmouth, writes: Brian Boughton said in his letter, Chronicle, March 6, that I describe myself as a nuclear physicist and that I write about the Large Hadron Collider and the Grand Unified Theory of physics as someone who knows nothing about the subject. That is an exceptionally ­foolish comment, but one that might be expected from an amateur who is way out of his depth and unable to support his case with cogent argument. His persistence with the Grand Unified Theory is a crashing mistake on his part. If readers will bear with me, I will briefly explain why. The nucleus is composed of various particles subject to a trinity of forces, each of which has been explained separately and, in recent years, the theoretical physicists have successfully brought them together under a single Grand Unified Theory. But there is another universal force to be accounted for ­somehow – the force of gravity. The Holy Grail of physics is to discover, eventually, an all-encompassing theory that both explains gravity and scoops up the Grand Unified Theory. This overarching theory has the charming name of the Theory of Everything. There are many ­eminent scientists, including Professor Stephen Hawking, who believe the Theory of Everything is not achievable. However, be that outcome as it may, it is the Theory of Everything that has some relevance to Brian Boughton's argument, not the intermediate Grand Unified Theory, which has none. It is a measure of Dr Boughton's inadequacy in the subject that he cannot even identify the right theory for his purpose. This is a monumental error, equivalent to someone commenting on the nature of religion and not being able to tell the difference between the Bible, the Koran, the Mahab-harata or a bus timetable. With such inability, how can any responsible person have credence in anything he says? When it comes to physics and the nature of matter, Dr Boughton is arguably a quack.