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For over 30 years, every major CAFC or SCOTUS decision about 101 patent eligibility – every single one, including Bilski, Mayo, and Alice – has compared the invention under consideration with the classic example of patent-eligible subject matter at the heart of Diamond v. Diehr. Indeed, such frequent citation and approval of Diehr’s rubber-curing invention by these later cases suggest that it is a quintessential example of patent-eligible subject matter.

However, these citations are deeply puzzling, because Diehr’s claimed invention appears to violate all of the Alice Court’s patent-eligibility rationale.



Diehr’s patent application presented the following claim:

1. A method of operating a rubber-molding press for precision molded compounds with the aid of a digital computer, comprising: providing said computer with a data base for said press including at least, natural logarithm conversion data (1n), the activation energy constant (C) unique to each batch of said compound being molded, and a constant (x) dependent upon the geometry of the particular mold of the press, initiating an interval timer in said computer upon the closure of the press for monitoring the elapsed time of said closure, constantly determining the temperature (Z) of the mold at a location closely adjacent to the mold cavity in the press during molding, constantly providing the computer with the temperature (Z), repetitively performing in the computer, at frequent intervals during each cure, integrations to calculate from the series of temperature determinations the Arrhenius equation for reaction time during the cure, which is where v is the total required cure time, repetitively comparing in the computer at frequent intervals during the cure each said calculation of the total required cure time calculated with the Arrhenius equation and said elapsed time, and opening the press automatically when a said comparison indicates completion of curing.

Now let’s consider how each of the Alice rationale might apply to Diehr’s claim:

“The problem addressed by Diehr’s invention is the process of curing rubber – which is centuries old, dating back to the 1800’s.”

“The heart of Diehr’s claim is the mathematical formula: ln(v) = CZ + x, which is inherently an abstract idea. However, the rate at which materials cure at different temperatures is not a technical invention, but a law of nature. Moreover, it is uncontested that the equation at the heart of Diehr’s claim was not invented by Diehr, but by Svante Arrhenius in 1884.”

“Diehr purportedly limits the claim scope to ‘curing rubber,’ but this field-of-use limitation is recited only in the preamble, which is non-limiting.”

“Notably, while the claim preamble recites ‘rubber-curing,’ the body of the claim more broadly recites ‘a compound’ which is heated within ‘a press.’ We therefore construe the claim as applying to the transformation of any compound using any press, as the body of the claim does not have the limitation that Diehr proposes.”

compound using press, as the body of the claim does not have the limitation that Diehr proposes.” “Diehr’s claim preempts the control of industrial processes using the Arrhenius equation, because Diehr has failed to demonstrate meaningful non-infringing uses of the Arrhenius equation in industry.”

“The steps of Diehr’s claim include ‘initiating a timer interval,’ ‘constantly determining the temperature,’ ‘constantly providing the temperature,’ ‘performing integrations to calculate the Arrhenius equation,’ etc. These steps recite conventional data processing, of the type that general-purpose computers routinely perform.”

“Diehr’s claim does not provide any specific algorithm by which the Arrhenius equation is to be used. The claims provide little more than the concept of controlling a boiler by estimating its progress using the Arrhenius equation, and some cursory calculation steps that amount to nothing more than the general statement: ‘apply it.'”

“The steps of Diehr’s claim do provide some specific details about how the calculation might be performed. However, such details are not relevant to the 101 determination.”

“The calculation at the heart of Diehr’s claim could be just as easily performed by a human being with pencil and paper. It may take a human longer, but the speed with which a computer may achieve a process that could also be completed in the human mind does not convert an abstract concept to a patent-eligible invention.”

“Diehr’s claim references properties such as ‘a constant (x) dependent upon the geometry of the particular mold of the press.’ Such terms are insolubly indefinite, as there is no limitation whatsoever placed on how the ‘constant’ reflects any specific property of the ‘geometry’ of the press. Further ambiguity resides in the phrase ‘determining the temperature (Z) of the mold at a location closely adjacent to the mold cavity,’ which does not teach one of ordinary skill in the art where, specifically, such temperature is measured – as ‘closely adjacent’ has no definite limitation.”

such temperature is measured – as ‘closely adjacent’ has no definite limitation.” “The claimed method does not provide a specific machine. It only provides a general-purpose computer, programmed with the Arrhenius equation in a non-specific way, and a tangential reference to ‘a press.’ These hardware are the basic tools of industrial processes, and were not invented by Diehr. Disregarding these conventional elements, what remains is a non-physical data processing method.”

“Diehr’s process provides data processing that concludes with control instructions to be delivered to a press. Notably, the claim does not actually claim the press itself, or the actual transformation of any physical article; it only recites processing data and issuing instructions. Without more, such systems do not qualify as patent-eligible subject matter, according to Parker v. Flook and Gottschalk v. Benson .”

and .” “For all of the foregoing reasons, in accordance with Mayo step 1, we will disregard the abstract concept of the Arrhenius equation for the purpose of determining patent eligibility under 35 USC 101. Proceeding to Mayo Step 2, we find that what remains of Diehr’s claim is a conventional description of controlling an industrial process.”

step 1, we will disregard the abstract concept of the Arrhenius equation for the purpose of determining patent eligibility under 35 USC 101. Proceeding to Mayo Step 2, we find that what remains of Diehr’s claim is a conventional description of controlling an industrial process.” “Allowing Diehr’s patent would preempt the use of the Arrhenius equation, a mathematical formula dating back to 1884, in the control of temperature-based industrial presses. Diehr’s patent would unfairly obstruct industrial processes – and disproportionately with the significance of Diehr’s contribution to the field, which is: applying an age-old formula to a long-known process using a general-purpose computer.”

The conclusion is inescapable:

What are we to make of this? How is it possible to reconcile the Court’s elevation of Diehr’s claim onto a pedestal of model patent-eligibility, with the immediately following reasons given for invalidating any desired patent that also squarely describe Diehr’s claim?

Looking past the Court’s empty homage to Diehr exposes Alice for what it is: an unconstrained, fact-free basis for invalidating any patent claim that ever has or ever will be issued by the USPTO. In this light, the Alice Court’s statement about “treading carefully in construing this exclusionary principle lest it swallow all of patent law” looks less like an admonition, and more like an objective. This deep, irreconcilable dissonance demonstrates that the patent-eligibility determination has come completely unmoored from rational, consistent, predictable analysis.

It is difficult to overstate the severity and urgency of this problem: this is the central, most pressing issue in U.S. patent law today. Unpredictability over a basic issue like patent eligibility can obstruct inventors, patentees, and competitors alike; conflicts are only resolved on a case-by-case basis, after several layers of litigation and judicial review. Every member of the patent community should be alarmed by this development, no matter their stance on any particular issue – because such uncertainty and inconsistency in the patent system equally hurts and threatens everyone.

There is one final, piercing bolt of irony in the conflict of Diehr and Alice. After citing Diehr with approval, the Alice opinion centrally focused on an application of the patent eligibility framework set forth in Mayo: “Step 1: Identify and exclude the abstract concept; Step 2: Consider whether the remaining elements add ‘something more.'” And yet, this very methodology was criticized in Diehr :

Respondents’ claims must be considered as a whole, it being inappropriate to dissect the claims into old and new elements and then to ignore the presence of the old elements in the analysis.

If Diehr were to have followed Alice rather than preceded it by 33 years, Diehr could only be read one way: as an explicit renouncement of the rationale of Alice.