In describing a situation wherein a poet (later) discovered a substantial similarity between a poem he wrote and one in a book he owned, Tom Bartlett wrote:
This kind of plagiarism—if that's even the right word—is a different beast entirely from the cut-and-paste variety. Copying is obviously wrong. But where, exactly, is the line between being influenced by a writer and ripping him or her off?
The concept of "plagiarism" is an academic construct. In the legal world, the issue is one of copyright infringement. As to federal law, one is free to copy unprotected works, but one cannot copy protected works without permission (license).
The issues in copyright infringement are laid out in a recent Sixth Circuit case, Bridgeport v. UMG:
To establish that it has been copied, a plaintiff must either introduce direct evidence of the
defendant’s copying or prove it indirectly by showing that the defendant had access to
the plaintiff’s work and that there is a substantial similarity between it and the
defendant’s work, thus giving rise to an inference of copying. See Ellis v. Diffie, 177
F.3d 503, 506 (6th Cir. 1999). Even if access cannot be proven, a plaintiff may prevail
by showing a high degree of similarity between the two works. See id. at 507.
Of "substantial similarity,"
The Sixth Circuit has condensed the substantial-similarity inquiry into a two-part
test: first, the court must “‘identify which aspects of the artist’s work, if any, are
protectible by copyright’” and, second, “‘determin[e] whether the allegedly infringing
work is substantially similar to the protectible elements of the artist’s work.’” Kohus,
328 F.3d at 855 (quoting Sturdza v. United Arab Emirates, 281 F.3d 1287, 1295-96
(D.C. Cir. 2002) (internal quotation marks deleted)). Put another way, “copying is an
essential element of infringement and substantial similarity between the plaintiff’s and
defendant’s works is an essential element of copying.” Wickham v. Knoxville Int’l
Energy Exposition, 739 F.2d 1094, 1097 (6th Cir. 1984). To complete the first step, the
court must “filter” out elements of the work that are not original to the author. Murray
Hill Publ’ns, Inc. v. Twentieth Century Fox Film Corp., 361 F.3d 312, 318 (6th Cir.
2004) (noting that the standard for originality is quite low and that the “vast majority of
works make the grade quite easily”) (quoting Feist, 499 U.S. at 361). Scènes à faire,2
the indispensable or standard aspects of a work, or those that “follow directly from
unprotectable ideas” should be filtered out as well. Id. at 319.
One has to distinguish the concepts of "plagiarism," which is primarily an academic construct, from "copyright infringement," which is a federal legal term (and which was at issue in the Harrison matter). As to federal law, one is free to copy that which is not protected, and one could indeed claim to be the author of Hamlet, without federal penalty (see Dastar). As to federal law, intent is not an issue, and one analyzes whether there is a substantial similarity of protectable elements. The case of Glenn Poshard at SIU raised the issue of inadvertent plagiarism in the context of Poshard's Ph.D. thesis.
*Comment on April 26-->
As a general matter, I agree with the remarks of esautovar72. The general rule is what makes the Sticklen case at Michigan State so remarkable.
As to tebartlett, there are at least two interesting aspects to the Poshard matter. First, several of the professors argued that proper citation procedures were not well-defined for Ph.D. theses at the time of Poshard's thesis. [!] Second, of more interest to me (and far less discussed), is the copying done at page 54 of the thesis, wherein a section summarizing the "state of the art" was taken from someone else's book, without attribution [a bad thing] but the time frame of the copied text was entirely inappropriate for use in the context it was copied! [a serious academic error that none on the committee noted] It wasn't just copying without attribution, it was irrelevant and inappropriate copying.
Neither the Sticklen case nor the Poshard case appear to be cryptomnesia.