Owl of Minerva
In Ted Honderich (ed.), The Oxford Companion to Philosophy, Oxford, 1995, pp. 638

Minerva, the Roman goddess of wisdom, was the equivalent of the Greek goddess Athena. She was associated with the owl, traditionally regarded as wise, and hence a metaphor for philosophy. Hegel wrote, in the preface to his Philosophy of Right: 'The owl of Minerva spreads its wings only with the falling of the dusk.' He meant that philosophy understands reality only after the event. It cannot prescribe how the world ought to be.

Bibliography

G. W. F. Hegel, Hegel's Philosophy of Right, tr. T. M. Knox (Oxford, 1967).

Utilitarian Philosophers :: Peter Singer :: 'Owl of Minerva'