## Friday, 27 August 2010

### Taxi-drivers and mechanistic determinism

The taxi driver who asked the philosopher Bertrand Russell what Life and the Universe is all about ('The old trouble returns', August 23rd) should really have known better than to look for guidance from such a source. Taxi drivers generally have a pretty good notion of what things are about, whereas no philosopher can distinguish his arras from a doorway in less than 3 chapters and 25 footnotes.

This may seem a trifle harsh, but it is I believe a widely held view, witness this week's New Scientist (28th August p.64) in which Richard Sutcliffe reports that his favourite road sign, often to be seen in Colorado is "Icy conditions may exist". He suggests this should be followed by the sign "Next philosopher 500 miles".

When I was in the Sixth form at school we used to have a subject called General Studies, where we were encouraged to ponder whether the statement "This sentence is false" is true or false, presumably to stop us thinking about big girls and their blouses.

It didn't work, and I retained a passing interest in both subjects until 1961 when I happened to be reading Philosophy XXXVI, pp.112- 127 by J.R. Lucas (as you do),and I came across the following arresting thought.

"Godel's theorem states that in any consistent system which is strong enough to produce simple arithmetic there are formulae which cannot be proved-in-the-system, but which we can see to be true. Essentially we consider the formula which says in effect 'This formula is unprovable-in-the-system.' If this formula were provable-in- the-system we should have a contradiction, for if it were provable-in-the-system then it would not be unprovable-in-the-system so that 'This formula is unprovable-in -the-system' would be false: equally if it were provable-in-the-system then it would not be false, but would be true since in any consistent system nothing false can be proved-in-the-system, but only truths. So the formula 'This formula is unprovable-in-the-system is not provable-in-the-system but unprovable-in-the-system. Further, if the formula 'This formula is unprovable in the system' is unprovable in the system, then it is true that that formula is unprovable in the system, that is 'This formula is unprovable' in the system is true".

It went on of course,.. and on,...and on, but after that I concentrated on the blouses.

I only mention this because some theologians now seem to be saying that since "the bogey of mechanistic determinism" has been overcome(see Philosopy XXXVI, p.112 if you're that interested) this shows there is a God! Crikey!