Proving a Negative Claim Limitation: A Tale of Three Nonprecedential Cases

By Daniel Hanson
September 12, 2019

“If a question arises again as to what standard of proof ought to be required when a negative claim limitation is in question, these three nonprecedential cases may actually offer some ‘guidance or persuasive reasoning,’ and it may be time for the Federal Circuit to make a ruling precedential.”

Federal CircuitIn the past 10 months, the issue of proving negative claim limitations has cropped up on appeals to the Federal Circuit. At least three panels of the Federal Circuit have addressed the issue, to one degree or another. Each panel has contributed, to some extent, to an understanding of the law. In dealing with the issue, each panel cited no precedent for doing so.

Curiously, all three decisions were designated as nonprecedential.

“An opinion or order which is designated as nonprecedential is one determined by the panel issuing it as not adding significantly to the body of law.” So says Federal Circuit Rule of Practice 32.1(b). Rule 32.1(d) adds: “The court may refer to a nonprecedential disposition in an opinion or order and may look to a nonprecedential disposition for guidance or persuasive reasoning but will not give one of its own nonprecedential dispositions the effect of binding precedent.”

The negative claim limitations issue is one that is almost certain to recur. Perhaps the next time the issue comes up, the decision ought to be precedential, and therefore, binding.

What Is a Negative Limitation?

Negative limitations in claims, generally speaking, curtail the breadth of a claim by expressly reciting an element that is absent or excluded. Furthermore, the negative limitation makes clear that absence or exclusion of the element from the claim is deliberate, not that the element is overlooked or optional or of little importance.

In the past, the Federal Circuit has addressed negative claim limitations in contexts such as definiteness and written description support. But the Federal Circuit has, until recently, given scant attention to a particular legal question:

When a claim is challenged as obvious or anticipated, what (if anything) must be proven to show that a negative claim limitation is disclosed by the prior art? (Proving a negative limitation in the context of an infringement action involves some different considerations, so this scenario is reserved for a later day.)


This Is an Easy Question, Isn’t It?

At first glance, since a negative limitation is something that the claim lacks, the answer would seem to be that no proof is needed, because there is nothing to prove. Yet saying that there is nothing to prove runs counter to the general rule that a challenger to patent claims has the burden to prove all elements when asserting anticipation or obviousness. Claim elements are never assumed to exist, and it is ordinarily not enough to show that a reference might include an element. So, if the challenger must prove something, what is it the challenger must prove?

At second glance, it would seem that if the cited reference is silent as to the element in question, then that ought to be proof enough. Yet, that does not quite satisfy the burden of proof either, since a negative limitation involves an element that is deliberately absent or excluded. Silence about an element is not excluding it, nor is silence the same thing as saying that the element is absent.

At third glance, perhaps one would need to have the prior art reference expressly or impliedly or inherently exclude the element. Such a level of proof, though likely sufficient to prove the negative limitation, is probably more proof than ought to be required. Just as a matter of experience and practicality, patents and printed publications do not routinely exclude elements.

At fourth glance, maybe it ought to be sufficient for a reference to say that the element is optional. This probably would be sufficient, as an optional element is, by definition, one that can be omitted without adversely affecting the basic operations being described. In the case where an element is not expressly identified as optional, a rule of reason must apply to determine whether an element is optional or not. It may be possible to drive an automobile without tires, for example, but doing so would have a significant adverse effect upon functionality, and it would be unreasonable (wouldn’t it?) to say that tires on a conventional car are optional. But once again, as a matter of experience and practicality, patents and printed publications do not routinely list an array of elements that might or might not be present.

Now up to our fifth glance, then, we come to three nonprecedential cases decided within the past 10 months.

The Google Case: November 2018

The first nonprecedential case is Google LLC v. Conversant Wireless Licensing S.A.R.L., No. 2017-2456 (Fed. Cir. Nov. 20, 2018) (before O’Malley, Chen & Stoll, Circuit Judges; opinion by Judge Chen). The negative limitation in the case was “wherein the method is performed without pre-registering the mobile station for the location finding service.”

The Google case turned more upon procedure than upon substance, but there is an interesting discussion there regarding proof of a negative limitation. The challenger in an inter partes review (IPR) argued that the element was shown because the “Staack [reference] nowhere discloses that pre-registration is required to access the location-based services.” In support of this argument, the challenger relied upon previous IPR rulings, one of which said that “[n]egative limitations may be satisfied by silence in the prior art”; the other ruling said that “a negative limitation requiring the absence of an element may be adequately described by a cited prior art reference if that reference does not otherwise require the presence of the element recited in the negative limitation.”

The Federal Circuit panel contributed to an understanding of the issue by acknowledging that these two standards are distinct. In the former, mere silence is all that need be shown. In the latter, it must be affirmatively shown that the element is not required. If silence alone were sufficient, that would remove any need to address whether the prior art indicated that the element was optional.

The patent owner responded that the cited reference did show the element in question, which was not excluded; and that what the reference indicated to be optional was “not germane.”

The Patent Trial and Appeal Board (PTAB) erred, said the Federal Circuit panel, by conflating the two standards: “Without explanation, the Board’s final written decision … conflated its analysis for Petitioners’ negative-limitation argument into its analysis for the non-instituted optional-feature argument.” Since the PTAB failed to address all key arguments, the panel decided that the appropriate course of action was to vacate and remand.

So, the Google case identified at least two distinct proposals by which a challenger may prove a negative limitation but did not say which (if either) was correct or permissible.

The IBM Case: April 2019

Less than six months later, the Federal Circuit decided another nonprecedential case, International Business Mach. Corp. v. Ianacu, No. 2018-1065 et al. (Fed. Cir. Apr. 1, 2019) (before Moore, Taranto and Chen, Circuit Judges; opinion by Judge Taranto). The negative limitation in the case was an authentication operation called a “single sign-on operation.” The use of the word “single” excluded two or more such operations. The PTAB found in an IPR that the patent owner’s claims were anticipated, and this appeal followed.

Without getting too bogged down in the details, the cited art dealt with “associating a meCard with an accessCard,” and the patent owner argued that this was not disclosing a “single sign-on.” The PTAB determined that the cited art “is silent as to what information is included in the accessCard,” so it was not shown that there really was another sign-on.

Unlike the Google case, this time the Federal Circuit panel did have a view as to whether mere silence was enough. “The overall finding that this portion of [the reference] teaches a process involving only one user authentication action is not supported by substantial evidence,” said the Federal Circuit. “To begin with, even if the Board were correct that [the reference] is ‘silent’ about the content of the accessCard, that characterization would not alone support a finding that there was no user authentication action in this scenario if, as appears, the Board meant that it simply could not tell one way or the other whether the accessCard contains credentials. Silence in that sense would not by itself suffice for the Petitioner to meet its burden to prove, by a preponderance of the evidence, that there was no user authentication action in this scenario” (emphasis in original).

Cited as indirect support for this proposition was 35 U.S.C. § 316(e): the statutory requirement that the challenger has the burden of proof. And for good measure, the panel mentioned that the defender had no burden to prove the opposite.

In the IBM case, “silence” seemed to be all that the PTAB had to go on. Other evidence in the case, including the prior art’s own disclosure and IBM’s expert testimony, indicated that that a “single sign-on operation” was not disclosed by the prior art.

So, the IBM case puts forth at least three important principles: One is that the challenger has a burden to prove something in order to establish an excluding limitation. A second principle is that proof of mere silence about the limitation in the prior art is not enough. And a third is that a defender can refer to the prior art disclosure and expert testimony to rebut the challenger’s challenge.

The WAG Acquisition Case: August 2019

Less than six months after the IBM case, the Federal Circuit issued a nonprecedential opinion in WAG Acquisition, LLC v. WebPower, Inc., No. 2018-1617 (Fed. Cir. Aug. 26, 2019) (before Newman, Chen, and Stoll, Circuit Judges; opinion by Judge Stoll). The limitation in question was “said server does not maintain a pointer into a buffer established within said server, for each said user.”

In an IPR, the patent owner argued that a pointer is inherent in the cited art. The PTAB disagreed and ruled that the claims were anticipated.

As a general rule, an element is inherent if it is necessarily present, even if it is not mentioned. E.g., Endo Pharmaceuticals Solutions v. Custopharm, Inc., 894 F.3d 1374, 1381 (Fed. Cir. 2018). In the WAG Acquisition case, the Federal Circuit focused upon whether the use of a pointer in the prior art was necessary. An unspoken assumption was that, if a pointer were indeed inherent in the prior art, then the pointer would not be an optional element, and the negative limitation would have been unproven.

Applying a substantial evidence test, the panel determined that there was sufficient basis in the record for finding that the pointer was an optional element in the prior art, and thus the negative limitation was indeed proven. The panel did not say that mere silence was enough to prove a negative limitation (and it does not appear from the opinion that any party so argued). Nor did the panel say that the patent owner had any sort of burden to prove inherency.

“A reasonable fact finder could find,” said the panel, “that [the] Carmel [reference] does not require use of a pointer for the reasons stated by the Board: Carmel emphasizes client control, lacks specialized server software, and uses pointerless protocols. While Carmel does not specify that a pointer is not used, nothing in the record suggests that a pointer must be used. The Board’s findings are therefore supported by substantial evidence” (emphasis in original).

This brief analysis says quite a lot. The challenger proved that the particular reference is not only consistent with a missing pointer, the reference also describes circumstances in which a pointer is expressly or impliedly unnecessary. The prior art need not expressly exclude the element, but there must be some sort of factual basis for finding that the element could be excluded; and that factual basis ought to be premised upon what the prior art reference does say, rather than upon what it does not say.

The rule of reason, mentioned above, is implied in the analysis of WAG Acquisition: if the element were excluded from a scenario described by the prior art, the prior art affirmatively indicates that that scenario would still reasonably work. It makes little sense to say that an element in the prior art is optional if removing that element would make the prior art scheme non-functional or otherwise problematic.

Now Would Be a Good Time for Some Binding Authority

We can leave aside the question of whether any of these three cases ought to have been precedential in the first place. If a question arises again as to what standard of proof ought to be required when a negative limitation is in question, the Federal Circuit may have no binding precedent to which it may turn. The three nonprecedential cases may actually offer some “guidance or persuasive reasoning,” however, and it may be time for a ruling to be precedential.

It is noteworthy that the three nonprecedential cases are mostly (though not entirely) consistent with one another, and the Federal Circuit may be able to look to the particular facts and reasoning of the cases to make the following principles binding:

  1. To establish anticipation or obviousness of a claim that has a negative limitation, a challenger has a burden to prove the limitation in some fashion. The negative limitation cannot be summarily ignored nor deemed self-proving.
  2. Mere silence in the prior art is not sufficient to prove a negative limitation. There must be other evidence showing that the element is or could be excluded.
  3. A prior art reference that expressly or impliedly or inherently excludes the element would be sufficient to meet the challenger’s burden; but a lesser showing by the challenger may also be sufficient.
  4. When the prior art expressly or impliedly discloses that the limitation is optional, then that would be sufficient to disclose the negative limitation; but there may be other ways to satisfy the burden of proof as well.
  5. If the defender can show that the element is inherent or otherwise necessary, that will defeat the challenge; but the defender does not have the burden to prove such a thing, and the defender may be able to defeat the challenge in other ways as well.
  6. Whether an element is necessary or optional in a prior art reference depends upon what the prior art reference does say, rather than upon its silence. This may involve some detailed analysis of the prior art, and whether it includes any disclosure or suggestion that the element in question could be omitted without substantially compromising the operation of what is disclosed in the prior art.



The Author

Daniel Hanson

Daniel Hanson is Senior In-House Patent Counsel for Huawei Canada who has worked with a number of law firms and corporations, including BlackBerry Ltd. in Canada. His practice focuses upon patent preparation and prosecution. The views expressed are his own.

Photo credit: Thanks to Rod MacIvor

Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of Read more.

Discuss this

There are currently 31 Comments comments.

  1. Anon2 September 13, 2019 9:57 am

    Nice article. Interesting analysis re. prior art, obviousness, support.

    The courts are struggling with claim limitations which were added during prosecution to get around the prior art, and often that which they refer to was never contemplated and not explicitly referred to the application as filed. Properly enabled and supported negative limitations are not an issue IMHO.

    IMHO This following not actually be a negative limitation:

    IBM: ‘The negative limitation in the case was an authentication operation called a “single sign-on operation.” ‘

    A table claimed as comprising “a support consisting of a single member” or a “support consisting of a single leg” IS narrow, but not a negative limitation. It defines the scope of the claimed table positively.

    Every claim explicitly disclaims that which properly falls outside of its defined scope, so every meaningful positive term in a claim which servers to narrow or specify the scope of the claim, excludes what it does not mean. In that sense EVERY term negates that which does not fall within its meaning.

    If the patentee wishes to include (of scope A+B) only scope A but exclude all of scope B, usually she claims A positively. But if A is not easily worded in the positive recourse to claiming A+B “without B” is made.

    Consider a table claimed as comprising “a support comprising a first member and no other member”, THIS would be a negative limitation, as would “a sign-on comprising a first sign-on operation and no other sign-on operation.”

    As a further digression, consider a square table with two circles cut out of it. Take THAT shape as a positive concrete, as it IS. IF there were a word in the English language for all flat shapes falling in such a class, a “flumboffem” say, then I could simply claim “a table top in the shape of a flumboffem”, quite simply and positively. Absent the term however, one must either do some pretty detailed claiming about the shape and perhaps there is a way to avoid negative claiming or resort to simple English; claiming something along the lines of a “square with two circles cut out of it” (or a shape having a square outer perimeter and two circular inner perimeters surrounding two circular voids) which IS going to involve some kind of negative limitation.

    WHAT is claimed is the same kind of thing, however, sometimes the language is on our side and sometimes it is not. Given that inventions are often quite novel, it’s not surprising some words for things like “every kind of X without a Y” or “all Cs that are absent a B” simply do not exist and we must resort to negative claiming.

    Hopefully the focus will be on WHAT is claimed not necessarily HOW it is claimed. Once one determines the scope of what IS claimed, the analyses should be relatively straightforward. IF however claim elements are added during prosecution to get around the prior art without any apparent specific support for that which they refer to in the application as originally filed… that can raise issues, and the article does a good job exploring them.

  2. TFCFM September 13, 2019 10:21 am

    Setting aside:

    – the post’s initial vagueness about the context in which the titular “Proving a Negative Claim Limitation” is to be considered (the author teases us with definiteness and the WDR before revealing that he’s going to consider the context of anticipation/obviousness over prior art)


    – the over-generalization of the topic embodied by asking-and-attempting-to-answer a very generic question about a topic that is inevitably very fact-specific to each matter,

    I think the author confuses the issue of claim interpretation by raising the issue of “intent.” The author writes:

    it would seem that if the cited reference is silent as to the element in question, then that ought to be proof enough. Yet, that does not quite satisfy the burden of proof either, since a negative limitation involves an element that is deliberately absent or excluded.

    It seems to me that the “deliberate”ness with which an inventor or his claim drafter sought to make an invention which lacks a feature or element has no bearing whatsoever on the meaning of a claim. The claim either “negatively” defines the invention by excluding the feature/element or it doesn’t.

    When a claim includes a negative limitation, the claim encompasses subject matter which lacks the negatively-defined feature/element. Accordingly, when comparing that claim with prior art, one must consider whether the art describes or fairly suggests *even one* embodiment that lacks the feature/element (and, of course, satisfies all other claim limitations).

    That the prior art embodiment only “accidentally,” “incidentally,” “non-deliberately,” or “unintentionally” omits the feature/elements matters NOT AT ALL. If the negatively-recited feature/element is absent from the prior art embodiment, then it is absent and the negative limitation is satisfied. The “deliberate”ness with which the maker of the prior art embodiment omitted the feature/element is utterly immaterial.

    In the face of “silence” in the prior art about whether an embodiment lacks the negatively-claimed feature/embodiment, the question simply reduces to the fact-specific question of how a POSITA reading the art would understand the presence/absence of the element. All three of the non-precedential cases cited turned on precisely this question — what the reference meant to a POSITA in the face of silence as to a negatively-recited limitation. (This fact likewise explains why all three cases were – appropriately – designated non-precedential.)

    It seems to me ridiculous to prescribe a rule that will predetermine the outcome of specific-to-the-matter factual analyses necessary to compare claimed subject matter with art-disclosed subject matter — especially when that analysis can be expected to come out one way under one set of factual circumstances and the opposite way under a different set of factual circumstances.

    Simply put, it seems to me, determination of factual questions which can vary wildly among technologies and individual patent claims calls for a flexible totality-of-the-circumstances-type test, not a rigid, formulaic one.

  3. frank coppa September 13, 2019 11:27 am

    Nice review of negative limitations; often a tricky claim element.

  4. JTD September 13, 2019 2:55 pm

    Thanks for sharing, Mr. Hanson. Food for thought. I had recommended a negative limitation just recently, and the applicant slightly balked. Negative limitations are kind of like sink wrenches. Not used very often, but you’re glad to have it in your toolbox when your sink is broken.

    My two cents: they are broad, they shouldn’t require any new special rules (existing precedent covers the main issues), and they should be seldom used.

    Anon2’s last paragraph sums it up well.

  5. Ken Weatherwax September 13, 2019 3:09 pm

    Interesting article. Though I wish it had better research or that I agreed with its recommended standard.

    Its main premise is that the Federal Circuit’s recent decisions on negative limitations (i) all were nonprecedential and (ii) all cited zero authority for their negative-limitation analyses. The author, however, overlooked a Federal Circuit decision earlier this year analyzing a negative limitation that not only was precedential, but cited authority for its analysis: AC Technologies, S.A. v., Inc., 912 F.3d 1358, 1367 (Fed. Cir. 2019) (“a reference need not state a feature’s absence in order to disclose a negative limitation.” (quoting Sud-Chemie, Inc. v. Multisorb Techs., Inc., 554 F.3d 1001, 1004-05 (Fed. Cir. 2009), which affirmed a finding that a reference disclosed “uncoated” film where it did not describe the film as coated and did not suggest necessity of coatings).

    I also respectfully but strongly disagree with the author’s proposed standard for showing a sufficient teaching of a negative limitation in the prior art. He proposes that “when the prior art expressly or impliedly discloses that the limitation is optional, then that would be sufficient to disclose the negative limitation.” That’s the wrong standard, especially as a matter of policy, and too anti-patent. Sometimes the whole point of an invention is the realization that something not only can be omitted but absolutely should be omitted.

    By the article’s proposed standard, for example, Dr. Lister’s invention of antiseptic surgery probably would not qualify as patentable over the combination of Dr. Semmelweis’s invention of washing the surgeon’s hands with bleach before surgery and Dr. Pasteur’s germ theory. Dr. Semmelweis recognized that when surgeons washed their hands with bleach before surgery the mothers’ fatality rate in hospital births dropped from 20% to 1%. His article taught no negative limitations—just the positive limitations of washing your hands with bleach before surgery. That’s because Dr. S was unaware of the existence of germs. It was Dr. Lister who read Dr. S’s article, then read an article about Dr. Pasteur’s germ theory, and then had the flash of genius that the true invention was to ensure that the hands and materials used in surgery did not have any germs on them. He therefore began using bandages that had been soaked with carbolic acid to wrap wounds, and discovered that post-treatment infections declined. Dr. Lister’s invention opened the door to surgery as more than an absolutely last resort, and saved millions of lives. And its key limitation is a negative, not a positive, limitation. Are we to conclude that Dr. Lister’s discovery, one of the most famous and important medical inventions in the history of the human race, would have been obvious from or anticipated by the Semmelweis-Pasteur combination so long as either Semmelweis or Pasteur had stated that it didn’t matter, and was thus optional, whether the materials used during surgery other than the surgeon’s hands were clean? Give me a break.

    The better standard is that if the claim limitation is that X must not be present, and the specification explains that it is important that X not be present, then the prior art must teach any person of ordinary skill in the art that X must not be present. If it teaches that it is merely optional, it could arguably be said to be teaching away from the invention, and certainly does not disclose it.

    Now, if Semmelweis-Pasteur had taught that making sure the bandages are sterile might help and might not help and therefore was optional, it might have been sufficient to render Dr. Lister’s invention obvious–but if Semmelweis-Pasteur had said that, that would be significantly different, and a significant scientific advance, from simply saying that it is indifferent to whether anything else but the surgeon’s hands needed to be sterilized, and it would have gone a long way toward reaching the conclusion that Dr. Lister reached. Ask yourself, in all seriousness: how much of that sort of disclosure would there have to have been in Semmelweis-Pasteur for you to conclude that Dr. Lister didn’t invent anything significant? Because that threshold, between Dr. Lister being an inventor and Dr. Lister being a mere ordinary artisan, is what the threshold of obviousness should be. And as for anticipation, such a disclosure of “maybe it matters, but it’s optional” most certainly should not, as a matter of policy, be considered sufficient to anticipate. Anticipation is supposed to be a narrow, exact doctrine, and Dr. Lister’s invention was certainly not the same as “maybe sterilization of the instruments and bandages might matter, but it’s optional.” It was better than that, and it would not have been anticipated.

    I could envision situations in which a negative limitation could be proved by a disclosure that it is optional, but that would be the situation where the patent says it is optional. So to me there are two classes of negative limitations here, the ones that are important to the invention and the ones that are what one might call design choices. My basic point is that the article’s proposed “merely-teaching-that-it’s-optional-is-always-sufficient” standard cannot be correct.

  6. Daniel Hanson September 16, 2019 3:18 pm

    Many thanks for the thoughtful comments, and special tip o’ the hat to Ken Weatherwax.

    It is correct that the AC Technologies case mentions “a reference need not state a feature’s absence in order to disclose a negative limitation.” That, however, is pretty much all the opinion says, and it does not say very much. And what is does say is consistent with my thesis. Moreover, the limitation is question was “independently of an access of the computer unit,” which is a limitation that is not necessarily viewed as a negative limitation, although AC argued it to be such.

    The Süd-Chemie case was cited as support, though not squarely on point. Moreover, this case involved a reference that indicated the element could be excluded, though it fell short of saying so explicitly: “As noted, Komatsu plainly teaches that containers can be made of films that are heat sealed without the use of adhesives, and thus without coatings.”

    So yes, these two cases touch upon the issue of negative limitations to some degree, but do not really add as much to the discussion as the three nonprecedential cases. And of course, the three nonprecedential cases did not mention them.

    With regard to the notion that the analysis ought to include some recognition that sometimes an element “absolutely should be omitted,” I find the argument intriguing. Nevertheless, I find it difficult to see how such an analysis is practical. If an invention includes limitations A, B, and C, and absolutely not D, then what effect is prior art that shows limitations A, B, C, and D, where the reference mentions that D is optional? Does that prior art not disclose, then, an embodiment in which A, B, and C are present, but that D (being optional) is certainly not present? It seems to me that the federal judges are going to have a hard time saying that there is a distinction that saves the claim.

  7. TFCFM September 16, 2019 3:26 pm

    @DH: “If an invention includes limitations A, B, and C, and absolutely not D, then what effect is prior art that shows limitations A, B, C, and D, where the reference mentions that D is optional?

    This seems to me exceedingly simple. The prior art clearly discloses two embodiments:
    – ABCD and
    – ABC.

    The latter embodiment appears to precisely match the “invention” you describe. Why would it not?

  8. Anon September 16, 2019 6:32 pm


    Perhaps it is a subtlety (and perhaps only a pyric result), but there IS a difference between “optionality” and “must not contain.”

    In fact, the teaching of “this may be optional” may even be said to be a teaching against “this must not contain.”

    Granted, the context matters, and there may be other factors involved that make the distinction not carry the day, but this is NOT as “exceedingly simple” as you suggest.

  9. TFCFM September 16, 2019 11:56 pm

    @anon: “this is NOT as “exceedingly simple” as you suggest.

    Explain to me, then, the supremely “complex” difference you discern between:

    – embodiment ABC (disclosed as an alternative to ABCD)


    – a claim that recites “limitations A, B, and C, and absolutely not D”

  10. Anon September 17, 2019 9:41 am

    The showing of “not exceedingly simple” is NOT the same as a showing of “supremely complex.”

    You keep on wanting to use a level of logic that just is not appropriate.

    No wonder B is so adamant in stating that you are not an attorney. Your exchanges show that you would not come close to passing the LSAT to even begin the process.

  11. TFCFM September 17, 2019 12:04 pm

    @Anon: “The showing of “not exceedingly simple” is NOT the same as a showing of “supremely complex.”

    Indulge me then, and explain (by any degree of simplicity/complexity you believe may be appropriate) the difference you discern between:

    – embodiment ABC (disclosed as an alternative to ABCD)


    – a claim that recites “limitations A, B, and C, and absolutely not D.”

    If I am, indeed, misunderstanding so fundamental a point, you would do me a great kindness by pointing out how.

  12. Anon September 17, 2019 1:50 pm

    Why should I “indulge” you?

    Of what good will that bring?

    The “how” SHOULD BE clear to you. As it would be to anyone who can pass the LSAT. the concept of optionality and the concept of “must” — and its offshoot of “must not” are — and should be — easy to understand logical sets that are different. YOUR expressed view attempts to make them out to be the same set.

  13. TFCFM September 17, 2019 2:12 pm

    @Anon: “ the concept of optionality and the concept of “must” — and its offshoot of “must not” are — and should be — easy to understand logical sets that are different.

    I fail to see how a reference that discloses “ABC or ABCD” fails to disclose “ABC (and not D).” Even assuming that “ABC and optionally D” is considered not to expressly disclose “ABC (without D),” what argument can *possibly* be made that it doesn’t render obvious “ABC (without D)”?

    (Again, not counting “because I/you say so!!!”)

    If you can’t explain so straight-forward an issue without name-calling and hand-waving, then I wonder if I haven’t been presuming you far more credible that may have been warranted. How, for example, would you explain the difference to an examiner rejecting your claim on such a basis?

  14. Anon September 18, 2019 7:00 am

    You are attempting to rephrase my point, TFCFM.

    Read again my point.

    As it is, and not how you would rather it to be.

  15. Anon2 September 18, 2019 9:20 am

    TFCFM @13

    You said:

    I fail to see how a reference that discloses “ABC or ABCD” fails to disclose “ABC (and not D).”

    I don’t want to wade in to an argument or presume to speak for Anon, but it would appear to me that:

    Example embodiments are presented, not as closed and exclusive illustrations, but as positive open ended exemplars of what is to be included in a concrete to qualify as an example of the invention according to that exemplar (and often only a subset of that constitutes the claimed invention as such). So an illustrated mechanism having parts ABC (or a process having steps ABC) does not imply that something with additional parts or steps J, K, or Z, etc. is not also an example of the invention according to the exemplar. After all, they all have ABC, are consistent variations thereof, and would themselves be examples of what is illustrated by the embodiment ABC.

    If illustrative embodiments were interpreted such that embodiment ABC MEANS ABC WITHOUT every other possible variation, i.e. if disclosing an embodiment ABC actually meant ABC and not D, ABC and not E, ABC and not F, ABC and not G, ad infinitum for everything under the sun, then all embodiments ABCJ, ABCK, etc. (literally everything except the naked embodiment ABC) would be exceptions to and inconsistent with the first example embodiment ABC. This would essentially disclaim everything except a literally naked example of the embodiment (and may in fact logically disclaim everything since nothing can be a naked embodiment as such).

    This would be untenable. It is in opposition to the purpose of describing embodiments and it is contrary to how their presence in a specification is rightly interpreted.

    Embodiment ABCD thus, is a further exemplar of ABC, with an optional additional (positively illustrated) feature D, (NOT a sort of opposite of an implicit ABC and not D). Therefore, illustrating “ABC or ABCD” (or embodiments ABC and ABCD) because of the open ended nature of embodiments IS equivalent to stating “ABC and optionally D” and hence does not disclose anything like “ABC AND NOT D”

    IMHO In order to teach, illustrate, or otherwise convey the idea of an embodiment which is actually “exclusive of D” some explicit reference to “not D” or at least a positive requirement of a K which logically or inherently necessitates “not D” is required.

  16. TFCFM September 18, 2019 12:55 pm

    @Anon2 “If illustrative embodiments were interpreted such that embodiment ABC MEANS ABC WITHOUT every other possible variation, i.e. if disclosing an embodiment ABC actually meant ABC and not D, ABC and not E, ABC and not F, ABC and not G, ad infinitum for everything under the sun, then…

    I don’t really disagree with anything you say, but I think that you ignore the hypothetical situation that was originally proposed. That situation was,

    (DH @#6): “…what effect is prior art that shows limitations A, B, C, and D, where the reference mentions that D is optional?

    My opinion, which I think is fairly unassailable, is that this prior art discloses ABCD and also discloses ABC. (What else could “optional” mean?) Whether E, F, G, H…. may or may not be present is both:

    – not stated in the hypothetical as being disclosed or not in the prior art


    – not relevant to the presence of D, which the prior art discloses can either be-present or not-be-present. For a claim that recites “no D,” the presence or absence of E, F, G… is irrelevant.

    More simply put, given that the hypothetical prior art clearly discloses ABC and ABCD, a claim to ABC, but no D seems clearly to be anticipated/obviated by embodiment ABC (i.e., no matter how “strongly one thinks/insists” that D is not present, D simply is not present in ABC).

    How, if at all, is this not true (without adding more to the hypothetical)?

  17. Anon September 18, 2019 4:36 pm


    This is not a matter of “ignoring the original hypothetical,” as it is a matter of dissecting the “logic” that you wanted to apply.

    There is error in your logic (now presented by two people — even as you ‘disagree’ with one but not the other).

  18. TFCFM September 18, 2019 5:44 pm

    @Anon: “There is error in your logic

    This is what I do not understand and wish you would explain. Where the prior art describes D as “optional,” no one seems to contest that this means two embodiments:
    1. ABC (i.e., no D is present).
    2. ABCD (i.e., D is present).

    Embodiment 1 appears, by any stretch of “logic” to satisfy a claim which recites A, B, and C, but no D.

    Please explain the supposed “error” of this logic.

  19. Anon September 18, 2019 7:25 pm

    Asked and answered TFCFM.

    Now by more than one person.

  20. TFCFM September 18, 2019 9:27 pm

    Dodging the question (in *every* conversation, it’s beginning to seem) fools folks no more than insult, misdirection, or hand-waving.

  21. Anon September 18, 2019 10:23 pm

    The fact that I have given you an answer means that I cannot have dodged the question.

    Rather, TFCFM, we have you not liking the answer, pretending not to understand the answer, admitting the point (finding nothing wrong) when someone else gives you the answer, and then accusing me falsely.

    Where exactly is the insult?
    Where exactly is the misdirection?
    Where exactly is the hand-waving?

  22. TFCFM September 19, 2019 12:32 pm

    I, for one, appreciate it when someone asks that I clarify what I said (since I have no deceit and/or ignorance to hide), because it:
    – signals to me that I may not have communicated well (poor communication is never my goal),
    – gives me an excuse to explain my view at greater length than I might previously have dared (out of fear of boring readers), and
    – provides me yet another opportunity to present my view (hopefully better than I did previously).

    That you avoid, seemingly, every opportunity to explain points on which you may have been vague, unclear, or evasive speaks volumes for your credibility.

    The issue is perfectly clear. It’s a well-known and accepted axiom that:

    That which infringes, if later, would anticipate, if earlier.” (Peters v. Active Mfg., USSCt, 1889; Upsher-SmithLabs. v. Pamlab, Fed. Cir. 2005)

    You would have us believe that this axiom depends upon what the inventor and accused-infringer were thinking, but have not explained why.

    Prior Art teaching “ABC(with D) and ABC(without D)”
    simply anticipates
    Patent Claim reciting “ABC(without D)”

    This is so regardless of the patent applicant thinking that the invention must “absolutely, positively double-dog NOT include D.”

    That you choose to believe and insist otherwise does not affect this truth.

  23. Anon September 19, 2019 4:20 pm

    I call BS on your “appreciation” of being asked to clarify things, as my questions of such nature in the past have typically gone ignored.

    But let’s give you a chance here. Above you accused me of three things and my reply was to ask you to “clarify” by providing exact examples of your accusations.

    Let’s see some answers.

  24. TFCFM September 19, 2019 6:29 pm

    I will reply to issues of substance, not childish nonsense. Last I checked, this blog is supposed to be about patent-related substantive issues, not your ego.

  25. Anon September 20, 2019 10:46 am

    Ah yes, TFCFM, you weasel out.

    You refuse to reply to my asking of you to substantiate YOUR accusations.

    Here’s a better idea: don’t make flippant accusations in the first place. You will save ALL of us the trouble of checking into “what this blog is supposed to be about.” The childish nonsense here is from you. Don’t like getting called out for it? Don’t do it in the first place.

  26. TFCFM September 20, 2019 11:38 am

    Anytime you want to discuss patent law-related substance, I’m here. If you want to discuss your ego and your childish behavior, I’m not interested.

  27. Anon September 20, 2019 2:01 pm

    Anytime you want to discuss patent law-related substance, I’m here.

    Again, I call BS – you’ve run away previously, and I certainly expect you to run away again.

    And it is your ego and childish behavior on display here. Trying to spin this as being a “me” thing is only more of the same choldish behavior from you.

  28. TFCFM September 20, 2019 2:40 pm

    If you’re serious, our substantive conversation dropped off at my questions at #18 above. If you want to discuss substance, let’s continue from there.

  29. Anon September 20, 2019 5:51 pm

    Substantive includes correcting the error of your logic.

    That you want to not involve such says that you are not serious about having a substantive conversation, but rather would only like to climb up on a soapbox and state your piece with no critical reflection.

    Your post at 18 is not sufficient for what you claim to desire. Posts 14, 15 and 17 remain for you to incorporate.

  30. TFCFM September 20, 2019 6:37 pm

    Whatever. You and your ego enjoy your nonsense.

  31. Anon September 21, 2019 10:58 am


    More BS from you as you accuse others of the game that you play. My correction of your logic NOT being engaged by you is not — and cannot be — a “my ego” thing, and is clearly a “YOUR ego” thing.

    That you say that you “are there” for substantive discussions is a bold-faced lie. You have repeatedly ONLY been there to stand on your soapbox and to simply ignore any critique of your position. Your pretending otherwise while engaging in the Accuse Others game fools no one.

    It is an exceptionally easy (and ego-free) thing for me to do to simply highlight your actions. You, of course, have control over what you want to say (and whether you actually engage with the counterpoints presented to you). But drop the pretense that you engage when you clearly do not do so.