MoorishGirl observes that recent scholarship indicates that Nathaniel Hawthorne may have borrowed passages from a poem by James Russell Lowell, and speculates that computer searches through Amazon and Google will turn up more such borrowings.
The default assumption in modern society is that plagiarism is bad. This attitude is hard to reconcile with the fact that many of our greatest artists plagiarized freely and unashamedly. The most noteworthy example is Shakespeare, who blithely stole his plots from other authors. Chaucer was no better. And I am told that early Classical musicians freely lifted each other's musical themes. Scholars such as Jonathon Livingston Lowes have suggested that "borrowing" from other works and transmuting them into art is an essential part of the creative process. The question becomes, then, whether the modern emphasis on originality and copyright has enhanced the creative process or hobbled it.