In Re Christensen

Posted by Unknown on Friday, April 14, 2006 with No comments


In the Matter of the Application of Dean M. Christensen (1973) F.2d 1392; 1973 CCPA LEXIS 341


US Court of Customs and Patent Appeals


Method of determining the porosity of subsurface formations. Rejected by the examiner under ß101, stating:
"the prior art teaches all the claimed steps except that drawn to computing the porosity of a formation. The essence of the appellant's invention lies in using data already available to one of ordinary skill in the art to compute the values of a parameter known to be of value in determining the geophysical properties of a formation... [T]he Appellant's point of departure from the teachings of the prior art lies in his applying his new formula to told data to calculate values of a known parameter. While this discovery of the appellant may constitute an important contribution to the art of geophysical prospecting, unless it falls within the four statutory subjects matter of 35 USCC 101 it cannot be protected by the patent laws." (cited at 1392)

The board agreed.


The rejection was affirmed by the court because the method claims, in which the point of novelty was a mathematical equation, was not a statutory method entitled to patent protection.


  • Mathematical formulae are unpatentable subject matter under ß101
  • The addition of the old and necessary antecedent steps of establishing values for the variables in the equation cannot convert the unpatentable method to patentable subject matter


A rare application by the CCPA of the point of novelty approach in determining what is the essence of the invention.

The case is also notable for the stinging attack which Rich J launches on the Benson decision. In a sense it sets the scene for the further development of disaprate jurisprudence by the CCPA and it's successor court in following the language of the statute rather than the algorithm inquiry.


Lane J
[1394] "We believe that Besnon must influence our decision in the instant case. Appellant's arguments, that Benson does not fully deal with the breadth of ß101 and does not suggest what view the Congress should take, do not render inapplicable what the Supreme Court said..."

[1394] "The issue considered by Benson was a narrow on, namely, is a formula for converting binary coded decimal numerals into pure binary numerals by a series of mathematical calculations a patentable process?"

[1394] "Given that the method of solving a mathematical equation may not be the subject of patent protection, it follows that the addition of the old and necessary antecedent steps of establishing values for the variables in the equation cannot convert the unpatentable method to patentable subject matter."

[1395] "In reaching our conclusion in the light of Benson, we find it unnecessary to discuss the correctness or the rationale of any of our prior decisions in a line of cases starting with In re Abrams... Each new appeal must be decided on its own facts..."

Rich J

[1395] "This case is quite unlike Benson, which we decided in 1971, and which the Supreme Court reversed. The rejection by the examiner in the present case was based on a combination of a holiding of obviousness under 35 USC 103, using two prior art references, and an application of the old "mental steps" doctrine. He found the only advance over the prior art to be the computation step, recited in the claims, which he said was "purely mental" and, in itself, therefore "non-statutory." He relied,primarily, for legal support, on this court's old opinions in In re Abrams, and in the companion case of In re Yuan, containing ideas which we have partially rejected and considerably refined in recent years...

In Benson, on the other hand, the sole rejection was purely and simply that the rejected method or process claims, as a whole, were directed to non-statutory subject matter in that they were not "processes" within the meaning of 35 USC 101... That was the only question we decided in Benson. That was the only question presented to the Supreme Court... Unfortunately, after stating that to be the question, the Supreme Court opinion does not again advert to it and never decides it, except inferentially by reversing our decision that the claims were directed to statutory processes. It ends up discussing the patentability of programs for digital computers but no program was before us in Benson. Nor is a program before us in this case. [emphasis added]

Since the issue in Benson was not the same as the issue in this case, one must ask what bearing the Supreme Court's Benson decision has here. The answer for me is that, notwithstanding the fact that the Supreme Court never discussed the issue presented to it, its opinion went on at some length about the "abstract and sweeping" scope of the claims, making that the pivot on which [1396] its decision turned, proceeding on the assumption - of doubtful validity - that the processed they defined could be carried out 'through any existing machinery or without any apparatus.' Having set up these hypothetical abstract and sweeping claims as the subject of its consideration, it treated them as for a "mathematical formula" or "the algorithm itself," because of its breadth, and as such, held them unpatentable.

Thus the reasoning of the Supreme Court's opinion has more bearing on the facts in this case than it had on the facts before it in Benson. The claims in this case do contain a mathematical formula; in Benson they did not. I therefore agree with Judge Lane that the Benson opinion 'must influence our decision in the instant case.'"

[1396] "It was made quite clear in the 'nutshell' summation in the Benson opinion that patents are not to issue where their effect would be to enable the patentee to prevent others from making use of a mathematical formula. That would be the effect here... If the processes claimed in Benson, having no practical application other than in operating a digital computer, constituted pre-emption of a formula, it follows that the processes claimed here pre-empt a formula notwithstanding they have application only to subsoil porosity determinations."

[1396] "But for the Benson decision, I would reverse the rejection here because I see no reason why such a specific, useful, technological process as a process for determining subsurface porosity, concededly a contribution to the useful arts, cannot be defined in the language of mathematics which is widely used as a medium of communication in the field. I have no moure doubt it is a 'process' within the meaning of ß101 than I had about Benson's process; but on that point I seem to have been reversed."