concurring in part.
I join the majority with respect to claim 15. However, I can only concur in the result reached by the majority with respect to claims 13 and 14.
The majority opinion properly holds that the board erred in considering the later state of the art in testing for compliance with the enablement requirement of 35 U.S.C. § 112, paragraph 1. However, in discussing this issue, it states:
' The pendency since 1953 of appellants’ applications, giving rise to concern over whether a claim may issue of breadth sufficient to encompass the later existing, “non-enabled” amorphous polymers of Edwards, . . . impel[s] clarification.
It then “clarifies” the matter by stating:
The PTO has not challenged appellants’ assertion that their 1953 application enabled those skilled in the art in 1953 to make and use “a solid polymer” as described in claim 13. Appellants disclosed, as the only then existing way to make *610such a polymer, a method of making the crystalline form. ... To restrict appellants to the crystalline form disclosed, under such circumstances, would be a poor way to stimulate invention . . , . To demand such restriction is merely to state a policy against broad protection for pioneer inventions
Absent evidence to the contrary, the language in a patent application is to be interpreted as it would have been at the time the application was filed. Although the PTO may rely on later art, it must show that the language used in that art would have meant the same to one skilled in the art at the time the patent application was filed. As this court stated in In re Voss, 557 F.2d 812, 819 n.15 (CCPA 1977):
[I]t is clear from the quotation from In re Fisher, 427 F.2d 833, 838, 57 CCPA 1099, 1106, 166 USPQ 18, 23 (1970), set forth in [footnote 6 of In re Glass, 492 F.2d 1228, 1232 (CCPA 1974),] that the PTO can rely on such later-issued patents and publications only if a showing is made that such claim language is the “language of the present art” as of the filing date of the application in question.
The majority opinion, in extended dicta, relies on In re Goffe, 542 F.2d 564 (CCPA 1976), for the proposition that restricting the claims to the crystalline form, preventing broad protection for a “pioneer” invention, would be “a policy both shortsighted and unsound from the standpoint of promoting progress in the useful arts . . .” However, the facts before us are clearly different from those in Goffe. There, the claim language, well defined in the prior art, clearly delineated the “outer boundaries” of the claimed subject matter, and the question was whether there was enablement for every embodiment within the scope of the claims. Here, the question is: in light of the interpretation of the claim language at the time the patent application was filed, what are the “outer boundaries” of the claims? Thus, Goffe is inapposite.
Contrary to the majority opinion, to permit the “outer boundaries” of a claim to be construed in light of later art, rather than in light of art at the time the patent application was filed, could well impede progress in the useful arts. For example, it would relegate a later species invention (e. g., the solid amorphous homopolymer of Edwards) to a subservient position vis-a-vis an earlier species invention (e. g., the solid crystalline homopolymer disclosed by appellants), even though the earlier inventor did not contemplate, much less enable, a generic invention, merely because the patent application for the earlier invention used a broad term which, at the time, had a meaning to one skilled in the art that was coextensive with the species.
The majority opinion notes that the PTO’s arguments evidence a concern that allowance of claim 13 might lead to enforcement efforts against later developers, but states that any conjecture on this point is “both irrelevant and unwarranted,” since “[t]he business of the PTO is patentability, not infringement”, and “the judicially-developed ‘reverse doctrine of equivalents,’ requiring interpretation of claims in light of the specification, may be safely relied upon to preclude improper enforcement against later developers.” (Emphasis in original. Footnote omitted.) Two comments seem appropriate. First, in saying that “[t]o restrict appellants to the crystalline form disclosed, under such circumstances, would be a poor way to stimulate invention,” the majority opinion advocates a double standard: for the inventor, interpret the language of the claims against later developers in light of the later state of the art; but for the PTO, as held here, interpret such language against the inventor only in light of the state of the art at the time the application was filed. I do not agree that such a double standard is needed to spur invention. Second, the PTO, in managing its business of patentability, has a duty to construe the scope of the claims, to interpret the claim language in light of the specification and the art existing at the time the patent application was filed, and to determine whether the scope of enablement is commensurate with the scope of the claims. If, *611on remand, the PTO should determine that, at the time appellants’ application was filed, one skilled in the art would have interpreted the phrase “solid homopolymer” broadly to include both crystalline and amorphous homopolymers, the PTO could, nevertheless, find that appellants’ disclosure was only enabling to make a crystalline homopolymer and could properly reject claims 13 and 14 under the first paragraph of 35 U.S.C. § 112 as of broader scope than the scope of enablement. On the other hand, if the PTO should determine that, at the time appellants’ application was filed, one skilled in the art would have interpreted the phrase “solid homopolymer” to include only a crystalline homopolymer, a finding of enablement, at the time appellants’ application was filed, to make a crystalline homopolymer would end the inquiry under § 112, first paragraph.