(Russell)

Mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.

(That is - too - when speaking of 'the arrow of time' etc. etc. via means of mathematical manipulations of formulae ... such exercises probably are covered in that blanket statement: which neatly slips in the Biggest bugaboo of all (?) an idea of the true. The whole topic IMO is squarely akin to all published essays on 'causality' - ie you/theProf are in metaphysics territory; love it or leave it. ;-)

:-\ufffd