"[3] This quote emphasizes the degree to which courts can have difficulty at the margins in deciding where ideas end and expression begins.
For this reason unlike in patent law, the court has to engage in a comparative analysis of the works in question in order to determine whether an infringement is present.
It is clear in the United States from cases like Rosenthal v. Kalpakian(which concerned the infringement of certain bee shaped jewellery that in the United States that there are occasions where the expression of the idea merges with the idea itself such that the expression cannot be the subject of copyright) "[4] that merger doctrine in an integral element of the copyright regime.
[5] In Delrina II Justice of the Appeal Morden noted that the U.S. doctrine of merger had been the subject of criticism in earlier Canadian and English caselaw in particular he quoted Justice Jacob in the English case of Ibcos Computer Ltd. v. Barclays Finance Ltd. who said with respect to the American doctrine of merger, "The true position is that where an 'idea' is sufficiently general, then even if the original work embodies it, the mere taking of that idea will not infringe.
It is a question of degree" suggesting that the doctrine of merger is inherent in the idea expression dichotomy and does not exist as an official principle of Canadian copyright law.
The scènes à faire doctrine states that certain elements of a creative work cannot be protected by copyright where they are mandated by or are customary to the genre.
The scènes à faire doctrine has been applied in Canada in Preston v. 20th Century Fox Ltd., where the plaintiff argued that the popular Star Wars franchise allegedly copied the Ewoks from his 1978 literary work titled Space Pets.