The Specification must “Fully Explain the Principle”

by Dennis Crouch

From 1793-1952, the Patent Act included a requirement that the specification “fully explain the principle” of any machine being patented.  That provision was eliminated in 1952.  My question, did that change reduce the disclosure requirement in any way?

= = =

The Patent Act of 1836 included the language now found in 35 U.S.C. 112(a) and that we identify as the enablement and written description requirements.  In particular, the statute required the inventor to provide “a written description of [the] invention, in such full, clear, and exact terms, as to enable any person skilled in the art or science to which it appertains, to make and construct the same.” 5 Stat. 117 (1836).

But, the 1836 statute did not stop there, it also included a further requirement for machine inventions:

and, in case of any machine, [the inventor] shall fully explain the principle, and the several modes of the application of the machine, so that it may be distinguished from other inventions.

Id.  This addendum was originally part of the Patents Act of 1793 and remained in the statute until the Patent Act of 1952.  It is not clear to me how the elimination of this requirement shifts the level of disclosure.  What do you think?

29 thoughts on “The Specification must “Fully Explain the Principle”

  1. 10

    Peltier devices were discovered in 1834, but the solid-state theory behind their workings wasn’t understood for over another 100 years. Product-by-process claims were once used to address situations such situations “where the product is novel and complex and cannot be described other than by the way it was made.”

    Judge Newman has written on this repeatedly.

    link to

  2. 9

    More often than not, one invents without knowing the actual “principle.” For instance, the people who invented gunpowder did not know that electron movement among valence shells was releasing energy. And even if you think you know it, how do you know you are right? Science seems to change the story every few centuries or so.

  3. 8

    Question…. doesn’t all this talk about the principle somehow relate to “abstractness” ? Can explaining the principle be used to argue against a bogus abstract sec. 101 rejection ? Hmm, think about an invention you’ve worked on….. is it always possible to state the principle, in one way only ? Or can the principle of an invention sometimes be stated in different ways ? We saw this with the IC tech of Texas Instruments, they didn’t even know themselves what the invention was until 15 yrs after the first spec was filed.

    Question 2: Is every invention for which a principle can be stated, inherently “abstract”, because Principles themselves are abstract ? I reckon most inventions can be stated as a principle that is abstract, because the nature of inventions is that they ALWAYS seem abstract, to ppl who didn’t know about the invention. The PTO delayed the Wright Bros. patent five years, because it was too abstract of an idea for them to handle.

    Question 3: How to differentiate between an abstract Principle and a concrete Principle ? Can a 101 abstractness rejection be obviated by stating your invention as a concrete Principle ? What elements are necessary for an abstract Principle to be transformed into a concrete One ?

    Can stating the Principle in a concrete way, help with abstract Sec. 101 rejections ?

    Thanks for bringing this topic up !

    1. 8.1

      No, this talk about the principle does NOT relate to “abstractness” — leastwise as such, given that the Supreme Court did not deign to actually provide a definition of Abstract.

      So without that basis, the answer is also “No,” in that explaining a principle cannot be used to argue against a bogus 101 rejection.

      Whether or not a principle “could be stated in only one way,” is a complete red herring. Not sure what you are thinking of with IC Tech of TI — as the item at point was not a legal requirement, and thus is not likely the thing that you are thinking of that “took 15 yrs after the first spec was filed.”

      Your second set is really no better. Again, as Abstract was not defined, your attempt to state that Principles are abstract is without tether. It is entirely unclear that Principles need be abstract (under any definition).

      As to “because the nature of inventions is that they ALWAYS seem abstract, to ppl who didn’t know about the invention.” you seem to want to use some colloquial meaning of ‘abstract,’ and even your example of the Wright brothers invention merely not being grasped does NOT mean that such was abstract.

      As to your set 3), you have really tied yourself in a knot as you now break your supposed reasoning in your first two question sets by allowing Principles to be “abstract” and “concrete” (you also thus DEFINE “abstract” to be “not concrete,” but methods are often NOT concrete, and the Act of 1952 not only provides for a whole statutory class of methods, but greatly EXPANDED that statutory class.

      You also “beg” for some “transformation,” and it entirely UNclear how you mean to use that word. May be you are (errantly) relying on the rejected Machine or Transformation clue?

      1. 8.1.1

        I think unless one can expound on most ideas with but a few short sentences, the brevity of wit known for soooo long is easily and instantly satisfied. Anything longer, Wit… Brevity… I writ what I wrote and am done, it was intended to spark, and has done its job 🙂

  4. 7

    I think the omission of the requirement to “fully explain the principle” of any machine being patented is a terrible mistake by Congress in 1952. Congress did not foresee in 1952 the thousands of foreign patent applicants filing patent applications in the USPTO that are often less than worthless in explaining the speculative inventions for foreign patent applicants. Approximately 60% of the patent applications I saw as a patent examiner were from foreign patent applicants with the ones from Asia often being unintelligible. However, due to the In Re Steele case by the CAFC, examiners are forced to examine applications that are gibberish. Basically, Asia applicants run their applications through Google translate and then submit them to the USPTO in bulk. I am talking thousands of garbage applications. I called a patent attorney about his gibberish application and he even refused to get a human to translate the claims because “his applicant wouldn’t pay money.” The backlog at the USPTO is due in large part to foreign governments abusing the USPTO and its examiners. The public and especially patent attorneys have no clue at what is faced by examiners at the USPTO.

    1. 7.1

      Thanks for that, I agree in toto. In a sense, the requirement to expound remains in the law, 112, de facto although not explicitly stated as it once was. A way for a practitioner to get into trouble is to use the words “means for ____”, without fully describing in the spec. more about what these “means” are, or their equivalents, we saw that a lot. Its rather easily accomplished given a good command of language and goes towards fully explaining the principle, since, if one can recite a few alternate “means for’s” in the spec, collectively they ought comprise some pretty good indicia re the principle of the invention.

      I keep bringing up “means for”, b/c IMO it got a lot of bad press, and the omission in the 1952 act IMO contributed to it by making practitioners “forget” over time, as we see even in the medical arts where they forget about old proven remedies, etc. Its not like, with “means for”, that ya can just write “means for” and expect it to cover everything under the sun for accomplish what’s recited after. UNLESS…… those means’ for are well known in the art. (A patent spec preferably omits that which is known to those skilled in the Art). I’d suspect when one can show that each “means for” as a claim element, is known in the art, life is easier. It can be a battle but you’ll win if you’re right. Thanks for the comment, its appreciated !

      1. 7.1.1

        No CW – in a sense the requirements existing in 112 are simply different requirements, and clearly are not the same requirement.

        And that is true absolutely regardless of the applicant CHOICE of using the optional claim format of 35 USC 112(f).

        In the immediate sense of your comment, multiple embodiments may – but importantly may NOT mean the same as the pre 1952 “fully explain the principle,” for at least in part, embodiments are just that: embodiments, and “explain the principle” means something else entirely.

        The omitted part is MOST likely actually related to 35 USC 103, in that knowledge and explaining the principle was simply considered neither sufficient NOR necessary to show and describe an invention (see the words of 103: “Patentability shall not be negated by the manner in which the invention was made.

        In other words, an invention is still an invention and every bit as patentable when the invention is made painstakingly through known steps that COULD BE described as per the pre-1952 words at point, JUST AS EQUALLY when an invention is made serendipitously in which the inventor has zero clue as to just how “the principle” works.

        “Hey, I just threw a bunch of different things in the bucket, and the bucket fell into the fire and out came this stuff” ==> invention merited.


          “Patents are, after all, nothing other than claims, and the support they find in the spec., and beaches, fine-grained West Michigan beaches, and their sunny-day denizens.” – C. Whewell


            OK – I think that brevity without addressing any of the points to which brevity is offered in response to is an absence of wit.

            You can go ahead and quote me on that – I’ll leave it then to you to put it into quotation marks.

    2. 7.2

      Criminy – somewhere in this there was a George Carlin filter trip….

      Your comment is awaiting moderation.

      May 8, 2022 at 4:59 pm

      Let’s start out by de bun k1ng the Examiner viewpoint of Jr.

      The public and especially patent attorneys have no clue at what is faced by examiners at the USPTO.


      often being unintelligible… forced to examine applications that are gibber1sh… he even refused to get a human to translate the claims because “his applicant wouldn’t pay money….

      You are doing it wrong.

      This type of “gar b a ge in” is – or should be if you were doing it right – quite easy to examine.

      You examine the material provided – AS provided.

      If the machine translation (as filed) is nonsense, then your rejection is made easier, and the patent attorney will be WANTING to do opposite of what you say and provide a better translation, or (if in fact correct), then the client will “get what they pay for,” and receive a rejection that cannot be overcome.

      Since this type of application is the opposite of “hard to examine,” AND EVERY applicant has paid the office for their turn of being examined under the law, your emotional rant of “foreign governments a bus 1ng the USPTO and its examiners” is utter balderdash.

      Lastly, there is a plain disconnect from the omission item (as NO applicant – foreign or domestic – will be doing so) and this examiner’s errant pet peeve. This means that his distinction between foreign and domestic filers cannot even reach the topic point, so it is entirely baseless for him to assert that this “abuse” runs from that change back in 1952.

  5. 6

    I think this clause partially captured the function that claims eventually took over. The clause became redundant once the claim requirement was instituted and then was finally removed in 1952.

    I do not think the clause’s removal in 1952 has any meaning vis-a0vis patent law in 1952.

    1. 6.1

      Well Bob, I can see some merit to your suggestion in that it would provide support for the judicial “interpretations” pre-1952 that have been provided on this thread that appear to flat out contradict the words of Congress.

      And while I am aware of the properunderstanding and treatment of separation of powers (which appears to be soon to be ig n0red by SC pundits), I am also aware that historically the necessary rigor concerning that doctrine has not always been in place.

  6. 5

    Dennis, what is not at all clear to me is what might, in this day and age, constitute “the principle”, let alone the “modes” of application of the claimed invention. I can well imagine that for those drafting the 1952 Statute it was even more unclear and so, fearing that retention of these words would befuddle the minds of not only those drafting specifications but also those of the judges hearing patent actions, they decided to leave any such wording out of the Statute.

    Good decision, no? For me, whether or not such obscure words are present in the Statute makes no significant difference to what constitutes a sufficient disclosure of the subject matter claimed.

  7. 4

    That omitted passage seems important since it embodies the concept of the basis of any life the lexicographer may breathe into claims which use means+function language. Absent at least some fulfillment of the omitted phrase in the spec, those using means+function language are bound to run into trouble.

    1. 4.1

      Not sure that I am understanding what point you are making with the Congress removing that phrase.

      Are you saying that this was part of the repudiation of Congress with what the Courts were doing, and the allowance by Congress to use terms sounding in function (and I would add that such was NOT as limited as your statement in view of the optional manner that of using TOTALLY functional claiming with the Means plus/Steps plus path).

      Your post — rather than “trouble” appears to bolster what Congress chose to do in the Act of 1952.

      There is only “trouble” if you don’t like what Congress did.

      1. 4.1.1

        Thanks. I was thinking more along the lines of the mindset of a patent atty. in 1951, vs., 1953. Did the dropping of the mentioned clause suddenly alter how lawyers wrote patents ? i.e., did they go forward ignoring the concepts in/ mertis of expounding on:

        “and, in case of any machine, [the inventor] shall fully explain the principle, and the several modes of the application of the machine, so that it may be distinguished from other inventions.”

        I’d reckon probably not, a good practitioner does this to the extent a particular development lends itself.

        I was thinking more along the lines of how much bad press all the “means plus function” stuff has gotten in the past few years, and pondered, maybe its just b/c a minority of patent writers forgot to expound as much as possible on the “means for” whatever, in the spec. and the omitted language seems to embody what ya’d be wantin and needin to do in any good spec anyway. As long as one can describe several embodiments (facts case-specific of course) of some aspect desirably claimed generically with the means+f, following the concept in that omitted clause is probably a good thing. I mean, prior to 1952 is when that phraseology was given more weight, and prior to 1952 is when means + F were more commonplace. So, if I have a point, it is that the two are joined. When ppl were running around using means + F in claim language, they had the notion of what’s in quotes above embedded in their heads. In 1953, very few had had time to forget. But by 2013, many had. And those are the ones who got in trouble, using means + F in claims, without heeding what’s embodied in that pre-1952 language.

        I’m not a huge fan of Means + F, but it remains a tool, for when circumstances lend well to it. I think a lot of ppl belive Means + F is something to be avoided like the plague, erroneously. They have their place, especially since computers are machines !!


          Well, I can only guess at was in the minds of patent prosecutors in 1953.

          Seeing as the Act of 1952 was far larger than any one single section (and the section at point here was certainly not the lead attention getter), I could easily surmise that while modes would still be covered, the dropping of a particular nuance of “fully explaining the principle” would easily be dropped (if but for the indications from the Court as has been provided by others on this thread).

          Would you have a reason to think otherwise?

          more along the lines of how much bad press all the “means plus function” stuff has gotten in the past few years

          I can easily guarantee you that such was not in the minds of practitioners in 1953.

  8. 3

    I do not think that the SCOTUS ever took this requirement too seriously. “It is certainly not necessary that [an inventor] understand or be able to state the scientific principles underlying his invention… .” Diamond Rubber Co. v. Consolidated Rubber Tire Co., 220 U.S. 428, 436 (1911).

  9. 2

    I think that it is disingenuous of you (as a teacher of patent law) to feign ign0rance.

    You may be being merely coy and wanting to tease out how others may view the change in law, but to think that “you don’t know” is just not believable. You certainly have a current understanding.

  10. 1

    Interesting. Were any reported applications or patents pre-1952 rejected for not providing that old statute requirement of “ case of any machine, [the inventor] shall fully explain the principle..” ?
    I would think the most likely would be “perpetual motion” machines, and wondered if that was the intended target?

    1. 1.1

      There probably is a lurking statutory construction question on what was meant by “the principle” in the pre-1952 statutes. There are at least two pre-1952 Patent Act Supreme Court cases expressly stating that the inventor does not have to “understand or be able to state the scientific principles underlying his invention.” Indeed, in one of the opinions, the Court instructed that “the law, [] only requires as a condition of its protection that the world be given something new and that the world be taught how to use it.”

      Diamond Rubber Co. of New York v. Consolidated Rubber Tire Co., 220 U.S. 428, 435-36, 31 S. Ct. 444, 447, 55 L. Ed. 527 (1911) (“A patentee may be baldly empirical, seeing nothing beyond his experiments and result . . . It is certainly not necessary that [an inventor] understand or be able to state the scientific principles underlying his invention, and it is immaterial whether he can stand a successful examination as to the speculative ideas involved. He must, indeed, make such disclosure and description of his invention that it may be put into practice. In this he must be clear. He must not put forth a puzzle for invention or experiment to solve, but the description is sufficient if those skilled in the art can understand it. This satisfies the law, which only requires as a condition of its protection that the world be given something new and that the world be taught how to use it. It is no concern of the world whether the principle upon which the new construction acts be obvious or obscure, so that it inheres in the new construction.” – upholding validity of patent claim to a tire that omitted step of cementing tire to rim because not cementing the tire to the rim allowed tire to better withstand lateral forces and strains and was a patentable improvement over the prior art)

      Eames v. Andrews, 122 U.S. 40, 55-56 (1887) (“It may be that the inventor did not know what the scientific principle was, or that, knowing it, he omitted, for accident or design, to set it forth. That does not vitiate the patent. He sets forth the process of mode of operation which ends in the result, and the means for working out the process or mode of operation. The principle referred to is only the why and wherefore. That is not required to be set forth . . .”)


          P.J. Federico’s commentary explained the change substituted the best-mode clause to (1) better match the invalidity provision in section 282, (2) generalize the requirement to all inventions (not just machines), and (3) clarify that mode referred to what the inventor considered the best mode (if any). Absent specific contrary authority, a judge would likely accept Federico’s account.


            Thanks RT – any link? It seems to be a vast difference in level of description.

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