It was, I believe, the formidable twentieth-century physicist Paul Dirac who suggested that scientists were busy making complicated things simple, while poets were busy making simple things complicated. Among many present-day physicists opinions are rather more open to the complexities of existence and the satisfactions to be had from their exploration in poetic form. In that spirit a small group of we Canterbury astrophysicists with just such a sympathy for the poetic enterprise meet occasionally in the local snug specifically to exchange poetic opinion and the occasional couplet.

A particularly favoured compilation and commentary amongst us is The Enthusiast Field Guide to Poetry (Quercus, 2007). As you'd expect, we prefer a clear definition from which to launch our investigations and the Guide duly obliges. Its introduction offers the following definition for poetry: 'as a highly charged arrangement of words… a poem presents multiple possibilities… possibilities ranging over innumerable fields'. Now the working physicist naturally feels the immediate need to quantify any such statement, the better to analyse its validity. The word 'multiple' is our clue and the mathematics simple, as I will explain, but first we ought to agree an underlying premise.

It's been said that if we can't think it, we can't know it -  a statement of the obvious but also something more. Both neuroscience and our personal experience suggest that we don't all think exclusively in verbal terms. However, sense perception and the thought processes initiated by it typically result in a fairly swift translation of apprehension and reflection into one's habitual native ...