Salvator Rosa (1615-1673)
Philosophy, about 1645
Wearing a scholar's cap and gown, the philosopher scrutinises the viewer, his stern expression corresponds with the Latin inscription on the stone tablet:
'Be silent, unless what you have to say Is better than silence.' Rosa was keenly interested in Stoic philosophy and used his own facial features for this characterisation.

I realise I have become increasingly silent. A good thing when I read back some of the tripe I write. I feel increasingly and inexorably incapable of expressing anything.