Limits to the use of common knowledge
As to written description:
If a skilled artisan would have understood the inventor to be in
possession of the claimed invention at the time of filing, even if every nuance of the claims is not explicitly described in the specification, then the adequate description requirement is met. See Vas-Cath Inc. v. Mahurkar, 935 F.2d 1555, 1563 (Fed. Cir. 1991); Martin v. Johnson, 454 F.2d 746, 751 (CCPA 1972) (stating “the description need not be in ipsis verbis [i.e., “in the same words”] to be sufficient”). See also MPEP § 2163.
Of "common knowledge":
As Appellants pointed out by citing MPEP § 2144.03(A), “[i]t is never appropriate to rely solely on ‘common knowledge’ in the art without evidentiary support in the record, as the principal evidence upon which a rejection was based.” See MPEP § 2144.03(A).