How does one motivate oneself to write a powerful essay on a subject which one feels emotionless about?

I am assigned to write an essay about William Golding’s views on life and society based on the novel Lord of the Flies. Unfortunately, I am just not feeling it. I normally have no problem writing, but I simply cannot get the words to come out this time. Everything that I write is coming across very cold and unconvincing, despite my best efforts to make it powerful and engaging. What can I do to make my essay strong when I do not feel so strongly myself?