I think this is the epithet of the ideal philosopher-poet. One seeks truth through the dispassionate contemplation of the thing. One seeks justice through the irrational enjoyment of people. Or something like that. The trick is not just to be irrational. Not just to be dispassionate. But to temper your irrationality with dispassion, or, which amounts to the same thing (though in a better sense than commonly assumed), to situate your passion within reason.