Sir, - It is good to note that Dr William Reville (November 16th) now seems to have altered his earlier conclusion that "time marches forward we all know".
His new and clearer position - that thermodynamic law demonstrates time direction only - is of course widely accepted by virtually everyone, while few have ever seriously argued that time must also "move, pass, march forward", as he originally maintained.
If, for example, time is defined as "the totality of regions we term past, present, future" then it appears quite obvious that not all of it can move. Indeed, if anything at all moves here, it must most simply be the "moving present" - or, more precisely, our everyday experience of the same!
Furthermore, Dr Reville's other contention - that thermodynamics provides the primary time arrow - is by no means universally agreed. Indeed, scientists list some five other similar time arrows or indicators of direction: cosmic expansion, wave radiation, k-meson decay, evolutionary trend, personal memories.
And of these the last might really be most basic - since all our current scientific laws may be just the latest expression of human mentality!
That our current notions on time are, then, very inadequate both Dr Reville and I would agree. Still, this situation is far from hopeless. Nor should it be muddled further by loose thinking about "time marching forward" and so on. - Yours, etc.
Dr Sean O'Donnell,
Shantalla Road,
Galway.