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Standard of proof for allowing amendments and corrections
III.E. Standard of proof for allowing amendments and corrections
In T 383/88 the board held that the normal standard of proof in proceedings before the boards of appeal, namely "the balance of probability", was inappropriate for determining the allowability of an amendment under Art. 123(2) EPC 1973. Instead, a rigorous standard, i.e. one equivalent to "beyond reasonable doubt" was considered by the board to be the right one to apply in such a case, since applying a lower standard could easily lead to undetected abuse by allowing amendments on the basis of ostensibly proven common general knowledge.
It had frequently been argued that certain technical features could be directly and unambiguously derived from a specification as filed by reading it in the light of common general knowledge. However, the board recommended viewing this approach with considerable caution. Firstly, the issue of the allowability of an amendment under Art. 123(2) EPC 1973 had to be decided by reference to what could be derived from the patent application as filed in the light of common general knowledge and not vice versa. Secondly, it was notoriously difficult to prove common general knowledge. For example, information might be generally disseminated, and therefore known within the community of skilled addressees, but it might well, at the same time, not be commonly accepted. Furthermore, too much reliance could not be placed on affidavit evidence from over-qualified persons, for the relevant knowledge was that of a notional, i.e. average, skilled addressee, and not that commanded by leaders in the relevant scientific discipline or field. The board added that it could not normally be the case that an affidavit by a single person was sufficient to discharge the burden of proof to the strict standard that was required (quoting T 383/88 in this respect see also T 1046/96, T 1239/03, T 1006/03).
In T 581/91 the board held that the balance of probabilities was not an appropriate criterion to be applied in a case where a correction under R. 88 EPC 1973 was at stake. Following decision T 383/88, the board stated that a more rigorous standard, that is one equivalent to "beyond reasonable doubt", ought to be applied.
In T 795/92 the board stated that Art. 123(2) EPC 1973 clearly precluded allowing an amendment if there was any doubt as to whether or not it was derivable from the original application. In the case at issue an upper limit of 89% indicated in claim 1 of the main request for the degree of nickel reduction was not expressly mentioned in the application as filed. The board decided that, in spite of a certain probability in favour of the appellant/patentee's position, the amendment was not allowable because there were various known methods for calculating this value, not all leading to identical results, and the application did not directly and unambiguously disclose which method had to be used.