Canada: Enfish Swims Over The Reefs Of Subject-Matter

Last Updated: May 26 2016
Article by Ken Bousfield

In Enfish, US 6,151,604 concerned a self-referential data storage and retrieval system for a computer memory. The invention improved the functioning of the computer by permitting faster database searching, and by having more easily modified database architecture.

At trial claim 17 was held invalid under 35 USC 101 for lack of patent-eligible subject-matter; invalid under 35 USC 112 for indefiniteness; and not infringed in any case. On appeal, the Federal Circuit reversed on 35 USC 101 and on 35 USC 112, but upheld the finding of non-infringement.

Somewhat ironically, the reversal on indefiniteness was also the Plaintiff's undoing on infringement.  The District Court had found the "means for" language of claim 17 indefinite. The Federal Circuit held that the "means for" was supported under 35 USC 112, 6th para., by a three-step functional description in the specification. However, when Enfish argued that the steps were optional permutations, and so encompassed the Microsoft product, the Federal Circuit bound Enfish to the embodiment described – which was not alternative: 35 USC 112, 6th para., is a two-sided blade.

Enfish has attracted attention under 35 USC 101, beginning with the understatement: "This court, as well as the Supreme Court, has long grappled with the exception that "[l]aws of nature, natural phenomena, and abstract ideas are not patentable"1.

The Federal Circuit applied a two-step Mayo/Alice test: first, to "... determine whether the claims at issue are directed to a patent-ineligible concept"2; second to "consider the elements of each claim both individually and 'as an ordered combination' to determine whether the additional elements 'transform the nature of the claim into a patent-eligible application."3

The Court noted: "The Supreme Court has not established a definitive rule to determine what constitutes an "abstract idea" sufficient to satisfy the first step of the Mayo/Alice inquiry"4 – bearing out the criticism heaped on "Abstract" by Stevens J., in Bilski.5

The Federal Circuit observed

  1. "fundamental economic and conventional business practices are often found to be abstract ideas, even if performed on a computer".6
  2. the "directed to" inquiry of Alice applies to whether the character of a claim as a whole is directed to excluded subject matter;7
  3. "The Supreme Court has suggested that claims purport[ing] to improve the functioning of the computer itself" or "improv[ing] an existing technological process" might not succumb to the abstract idea exception."8

Enfish leans away from discussions of "abstract", and more toward technology:

"We do not read Alice to broadly hold that all improvements in computer-related technology are inherently abstract ... Indeed, some improvements in computer-related technology ... are undoubtedly not abstract .... Nor do we think that claims directed to software, as opposed to hardware, are inherently abstract ... Software can make non-abstract improvements to computer technology just as hardware improvements can, .... We thus see no reason to conclude that all claims directed to improvements in computer-related technology, including those directed to software, are abstract ..."

"For that reason, the first step ... asks whether the focus of the claims is on the specific asserted improvement in computer capabilities  ... or, instead, on a process that qualifies as an "abstract idea" for which computers are invoked merely as a tool."

Enfish is thus an encouraging confirmation of Chatfield 9,10. The Markey C.J. opinion in Chatfield continues to stand as a beacon of common sense on software.

Labels like "software" and "algorithm" tend to be distractions that obscure the fact that all software and algorithms are, ultimately, collections of method steps11Chatfield, itself, is the descendant of Boulton v. Bull12. As in Enfish and Chatfield, Watt's invention pertained to an improved way of operating existing machinery.  At the time, it was controversial whether methods were included within the meaning of "manufactures" under s. 6 of the Statute of Monopolies. Watt's method was the "software" of its day.

The inclusion of the expansive statutory classes in the US Patent Act of 1790 was a reaction to that controversy, intended to leave no doubt that everything within Science and the Useful Arts of Art. 1, s. 8 of the Constitution was potentially patent-eligible.

The statement that "fundamental economic and conventional business practices are often found to be abstract ideas" is really a recognition that business practices lie outside Art. 1, s. 8,13 not because they are "Abstract" but because they are neither Science nor the Useful Arts. The purpose of the Statute of Monopolies was to outlaw business practice monopolies, primarily to curtail the power of the Guilds.  Section 6 was the exception.

Under US Patent law, since well before 1890, there has always been a requirement that patent eligible inventions must have (a) a creative component, i.e., an idea;  (b) a practical component; and (c) coherence between (a) and (b) to form a unified whole. Without all three, there is no invention, patent-eligible or otherwise.

The prohibition in Diehr and Prometheus against cosmetic enhancement through conventional pre- and post-processing steps is about coherence:  the invention "as a whole" must be "directed to" patent-eligible subject-matter.  Lack of coherence cannot be solved by clever drafting: it requires an actual invention.

Subject-matter analyses based on "Abstract", "Natural Phenomena" and "Laws of Nature" tend to provide little guidance.  A more reliable approach is:

  1. Has an actual invention been made? Is there (a) a creative idea; (b) a practical means; and (c) coherence between (a) and (b)?
    Many diagnostic and software claims fail the coherence test.  Enfish passed easily: the software was about improved operation of the machine.
  2. Is the invention within Science and the Useful Arts?
    This is where business and financial software claims fail.  Enfish passed easily.
  3. Is the invention within at least one statutory class?
    If an invention is within Science and the Useful Arts, it is almost impossible to be outside the statutory classes.
  4. Do the claims "particularly point out and distinctly claim" the subject-matter of the invention?  I.e., has the invention been claimed intelligibly?
    Many software claims, and some diagnostic claims, fail under 35 USC 112, 2nd para. Enfish scraped past, saved by 35 USC 112, 6th para.

On subject-matter, Enfish was an easy case.


1 Enfish, p. 9, lines 10 – 13.

2 Alice Corp. Pty. Ltd. v. CLS Bank Int'l 134 S. Ct. 2347, 2355 (2014).

3 Mayo Collaborative Servs. v. Prometheus Labs., Inc., 132 S. Ct. 1289, 1298, 1297 (2014).

4 Enfish, p. 9, lines 27 – 30.

5 Bilski v. Kappos, 561 US 593 (2010).

6 Enfish, p. 10, lines 4 – 7.

7 Enfish, p 10, lines 22 – 26.

8 Enfish, p. 10, lines 31 – 34

9 Application of Chatfield – 545 F 2d 152, 191 USPQ 730 (Cust & Pat App, 1976). See also In re Iwahashi, 888 F 2d 1370 (Fed Cir 1989);  Ex Parte McNabb and Voss, 127 USPQ 456 (Pat Off Bd App, 1960).

10 The Canadian equivalent is Honeywell Information Systems Inc., Re (1986), 13 CPR (3d) 462 (PAB).  See also: CA 1,180,813 of Dialog Systems (1984), 5 CPR (3d) 423.

11 Ex Parte Kahn, 124 USPQ 51 (Pat Off Bd App, 1960) The method of operating the machine more efficiently did not become unpatentable simply because it was called an "algorithm": See Diamond v Diehr, 450 US 175 (1981) at 187: "Our earlier opinions lend support to our present conclusion that a claim drawn to subject-matter otherwise statutory does not become nonstatutory simply because it uses a mathematical formula, computer program, or digital computer."

12 Boulton & Watt v Bull (1795), 2 H Bl 463, 126 ER 651; Hornblower v Boulton (1799), 8 Term Rep 95.

13 In the Canadian context, s. 27(3)(b) of the Patent Act.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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