Why Choueifaty is wrong
In 2020, the Federal Court of Canada decided an important case on subject matter eligibility of computer implemented inventions: Choueifaty v. Attorney General of Canada 2020FC 837. Briefly I explain why the decision in Choueifaty is at least analytically wrong, although I take no position, at this time, as to whether the case was correctly decided as to subject matter eligibility, only that it was decided for the wrong reasons.
“Patent law concepts are already notoriously difficult to apply correctly, especially when one does not have an intimate knowledge of how each concept evolved and why. Although it may be appropriate in certain cases to borrow from one concept to explain another or to treat them together, this must be done with extreme caution, and only with a deep appreciation of the distinctions. Otherwise, it will result in more uncertainty in the law and, often, in an error of law.”
Bombardier Recreational Products Inc. v. Arctic Cat, Inc. 2018 FCA 172, , 159 C.P.R. (4th) 319 paragraph 64. This observation from Justice Gauthier unfortunately does appear to be the case. But why? Lawyers are used to interpreting words, even technical terms, but perhaps in no other area of the law do we patent lawyers get twisted into contortions over simple words.
The fact remains, when all the dross is removed, all that should happen is that the claim will be interpreted by a judge through the eyes of a person skilled in the art. Does it really matter if it is a one step or two step or a multiple steps process?. Surely “purposive” means just that, to give understanding to the claim in the context of the purpose for which the invention was made, whether you do that after, before or during a literal reading. When considering the claim “purposively” what better way to understand that purpose than by examining the problem that the invention was hoping to solve and the solution? Yet Mr. Justice Zinn held that the problem and solution approach was the incorrect approach and inconsistent with Free World Trust because it is somehow equivalent to the “substance of the invention” approach discredited in Free World Trust.
This is the first of Justice Zinn’s analytical errors. While not a mandatory part of any claim construction analysis, surely the “problem solution approach” is a more rigorous analytical approach that is in no way equivalent to blindly asking what is the “substance of the invention” or the “spirit of the invention”.
The Court itself in Free World considered both the problem and the solution set out in the patents in suit when examining the prior art: “It is clear, with respect, that the Solov'eva article does not address, let alone solve, the technical problems dealt with in the patents in suit.” (Free World Trust c. Électro Santé Inc paragraph 27. 2000 SCC 66,  2 S.C.R. 1024, 9 C.P.R. (4th) 168).
The Free World Trust analysis does not dismiss or disregard an examination of the problem and the solution while analyzing a claim, but rather, in substance, supports it. Later in the same paragraph, the Court states: “Although the various components were earlier known to persons skilled in the art, the inventor brought the elements together to achieve what the Commissioner of Patents considered a new, useful and ingenious result”. Free World Trust c Électro Santé Inc, 2000 SCC 66 at para 27. Is this not a review of the problem and its solution (the “ingenious result”)? Whatever the Supreme Court may have said in Free World what they did was (at least in part) look at the problem and the resulting solution and nowhere did the Court dismiss this approach. There is no basis for concluding that the problem solution approach is inconsistent with the cannons of construction in Free World or in concluding that this approach is equivalent to the discredited “substance of the invention” or “spirit of the invention”, which unlike the problem solution approach, is admittedly too vague and uncertain to be a guide to claim construction.
Now we turn to the second analytical error. The law around “essential elements” is fraught with difficulties, many of which have been set out in the excellent article by Dimock et al in Issue 36 of the CIPR and in the analysis of Justice Locke in Shire Canada v. Apotex at paragraphs 134-143 (referred to by Justice Zinn at paragraph 39 of Choueifaty.) While lists of criteria are convenient, they are often dangerous. The Court’s paraphrasing of the UK Improver tests has proven difficult to decipher. The Court in Free World expressly said that their test was not limiting. ( Free World Trust paragraph 56, “ three questions are not exhaustive but they encapsulate the heart of Lord Diplock's analysis, and have been endorsed in subsequent English cases.”) Nevertheless, the modified Improver test has often been applied in a closed way to the exclusion of any other enquiry which might enlighten or add context to whether an element is essential or not. When speaking of the Catnic tests in the context,the Lord Hoffman (himself the reformulator of the Improver questions) recognized that they are too often blindly followed:
“When speaking of the "Catnic principle" it is important to distinguish between, on the one hand, the principle of purposive construction which I have said gives effect to the requirements of the Protocol [The Protocol on the Interpretation of Article 69 of the European Patent Convention], and on the other hand, the guidelines for applying that principle to equivalents, which are encapsulated in the Protocol questions. The former is the bedrock of patent construction, universally applicable. The latter are only guidelines, more useful in some cases than in others. [emphasis added] I am bound to say that the cases show a tendency for counsel to treat the Protocol questions as legal rules rather than guides which will in appropriate cases help to decide what the skilled man would have understood the patentee to mean.” Kirin-Amgen, Inc. v Hoechst Marion Roussel Ltd  UKHL 46.
In analyzing the Free World test, Justice Zinn concludes that the problem-solution approach fails to respond to the issue of the inventor’s intention (paragraph 39). This is where the second analytical error occurred.
With the greatest respect to Justice Zinn, I have difficulty seeing how the problem-solution approach fails to respond to the issue of the inventor’s intention. It seems obvious that if you want to know what the intention of the inventor is, you would at least try to understand what the problem was that the invention hoped to solve and the solution that the invention sought to put forward. It may be that in some cases, the problem solution approach does not provide the complete answer but it is surely right to use this approach as one part of the analysis. It must be remembered that the intention of the inventor is not the subjective intention of the inventor.
This has been clearly articulated by Justice Gauthier in Bombardier (Bombardier Recreational Products Inc. v. Arctic Cat, Inc. 2018 FCA 172, 159 C.P.R. (4th) 319, at paragraph 23-24.): “The Supreme Court of Canada was clear that although purposive interpretation can be viewed as an attempt to determine the intention of the inventor, one does not seek to establish the subjective intention of the inventor. Rather, one must seek to determine the objective intention as it was expressed in the patent itself, and as would be understood by the person to whom it is addressed (Free World Trust at paras. 58-67; Whirlpool Corp. at para. 49).
Thus, apart from the specification itself, the only evidence that should be considered to inform a court's analysis of a claim, is proper evidence as to how the POSITA would understand it in light of his or her relevant common general knowledge in the context of the specification as a whole.”
Surely an understanding of how the POSITA would understand the intention of the inventor would be informed by the problem found in the common general knowledge and the solution proposed by the claimed invention. Thus an analysis of the “problem” that the invention hopes to solve and its “solution’ can be an aid to the objective understanding of the inventor’s intention.
Unfortunately, Choueifaty was not appealed. It may be that some clarification of the use of the problem-solution approach may appear in the upcoming case of Benjamin Moore v. The Attorney General of Canada T-1340-20.