Keats, "The Tyger," and the appeal of melancholy

I know this seems random but the first thing I thought after reading Keats' "Ode on Melancholy" was how much it reminded me of William Blake's "The Tyger." In that poem, Blake poses the question; who created evil? Could God, the creator of good, have also introduced the terrible tyger into the world? Ultimately, I think Blake decided that the existence of good and evil is a necessary paradox. Indeed, each is defined in terms of its opposite and so they cannot exist without one another. More importantly, I believe Blake asserts in his poem that evil is not only necessary, but can be beautiful as well.

For me, this notion connects intimately with what Keats is saying in "Ode on Melancholy." Melancholy, like happiness, must be celebrated because it is a fleeting, powerful human emotion and without it we could never come to appreciate happiness the way we do. Having said that, I think most people would agree that melancholy is a necessary part of life -- that seems fairly obvious. Keats, however, takes this notion a step further by declaring melancholy attractive in and of itself. The poet flirts with this attraction in both "Ode to a Nightingale" and "Ode on Melancholy." That Keats says he is "half in love with easeful death" is probably the most easily identifiable evidence for this odd relationship.