Universal Postal Union Raphael 10c 1974 issue U.S. stamp

The figure is shown in a pensive, melancholic pose, leaning his head on his left hand while writing on a block of marble. He wears a heavy violet tunic and boots, seated apart from the other philosophers in the original composition. The stamp includes a quote from the poet John Donne and commemorates the centenary of the Universal Postal Union.

Heraclitus represents the pre-Socratic doctrine of universal flux and was included by Raphael as a tribute to Michelangelo; the figure embodies the Renaissance concept of the melancholic genius. The work belongs to the Neoplatonic program of the Stanza della Segnatura, which sought to harmonize ancient philosophy with Christian theology.