An invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art (Art. 56, first sentence EPC). The "state of the art" for the purposes of considering inventive step is as defined in Art. 54(2) EPC. It does not include later published European applications referred to in Art. 54(3) EPC. Such earlier applications are part of the state of the art only when considering novelty and not when considering inventive step (see Guidelines G‑IV, 5.1 and G‑VII, 2 – November 2018 version).

Technical progress is not a requirement for patentability under the EPC. Therefore, technical progress shown in comparison with marketed products as an alleged support for inventive step cannot be a substitute for the demonstration of inventive step with regard to the relevant closest state of the art (see T 181/82, OJ 1984, 401; T 164/83, OJ 1987, 149; T 317/88; T 385/94; T 850/02).

The extent of the monopoly conferred by a patent should correspond to and be justified by the technical contribution to the art. This general principle of law, applied in T 409/91 (OJ 1994, 653) and T 435/91 (OJ 1995, 188) (albeit to determine the scope of protection justified under Art. 83 EPC 1973 and Art. 84 EPC 1973), also applies to decisions under Art. 56 EPC 1973, because everything covered by a legally valid claim has to be inventive (see also T 1060/11). Otherwise the claim has to be amended, by deleting anything obvious to ensure that the monopoly is justified (T 939/92, OJ 1996, 309; T 930/94; T 795/93; T 714/97).