Glassy Essence

“… but man, proud man,
Drest in a little brief authority,
Most ignorant of what he is most assured,
His glassy essence, like an angry ape,
Plays such fanstastic tricks before high heaven
As make the angels weep; who, with our spleens,
Would all themselves laugh mortal.

– Isabella’s exclamation, in Shakespeare’s Measure for Measure, II.ii. 110-123