Sir: I was surprised by the puzzlement which greeted William Waldegrave's reference to the 'owl of Minerva' which 'flies only at dusk', during a speech on the Civil Service reforms reported by Andrew Marr (14 July). He was of course alluding to a famous passage in G. W. F. Hegel's Philosophy of Right. The 'owl of Minerva' stands for philosophy itself. Hegel uses the metaphor to illustrate the point that philosophy is merely its own time comprehended in thought, a necessarily limited conceptualisation of temporary actuality. Hegel proceeds to highlight the perils which confront philosophers in 'issuing instructions on how the world ought to be' from a position of such relatively premature understanding. Doubtless Mr Waldegrave is aware of such dangers as he prepares to remodel the Civil Service along what he deems more 'efficient' lines.