Folly, let us say, is "the wisdom of the heart", the error in thinking that is caused by feeling, the unreasonableness of passion. But it is not simply a defect. Its ground is in something positive: our emotions. And this is why Erasmus was able to sing its praises.

Spinoza talked about "the intellectual love of a thing". What is to passion as folly is to reason? What do we call the loss of feeling that is caused by thinking, the dispassionateness of reason? Melancholy. Dowland would find his composure there.