a) Arbitrary choice from a host of possible solutions 

A merely arbitrary choice from a host of possible solutions cannot be considered inventive if not justified by a hitherto unknown technical effect that distinguishes the claimed solution from the other solutions (T 939/92, OJ 1996, 309; T 739/08; T 1175/14; T 2554/16; T 1148/15; T 115/18; T 1984/15; T 1862/15, T 1445/21). In T 400/98 the board stated that applying one of the possible solutions which were available to the skilled person required no particular skills and hence did not involve an inventive step (see also T 107/02). In T 1984/15 the board held that both single and repeated arbitrary choices were part of the skilled person's routine approach to providing an alternative solution.

In T 1862/15 the board held that in a case involving an arbitrary selection, the prior art did not need to contain an incentive for the skilled person to select the particular solution claimed. Instead, all possible solutions had to be regarded as being equally suitable and obvious candidates for solving the objective technical problem; therefore, they all had to be considered to be suggested to the skilled person. See also T 2029/21 in which decision the board held that where the problem to be solved resided in the provision of a mere alternative, no suggestion in the prior art was needed in order to render the subject-matter claimed obvious. Rather, it was sufficient to show that said missing features constituted an arbitrary selection within a host of available alternatives.

In T 588/99 the board stated that in the particular situation where a document explicitly defined any compound having a certain activity as a suitable component of a detergent composition, and urged the skilled person to look for such compounds in publications of other technical fields such as biochemistry and medicine, it required no inventive activity to solve the technical problem of providing an alternative to the compositions disclosed in such prior art by replacing the explicitly specified compounds having the given activity with any other such compounds which may be found by exploring the other technical fields.

In T 1941/12 the board stated inter alia that an arbitrary selection of strains, by the very fact of it being arbitrary, did not involve any inventive step. This was even more so since the two specific strains chosen were known from the prior art as commercially available.

In T 892/08 the board referred to the established case law whereby, when the technical problem is simply that of providing a further composition of matter or a further method, i.e. an alternative to the prior art, any feature or combination of features already conventional for that sort of composition of matter or method represented an equally suggested or obvious solution to the posed problem. The boards have repeatedly established that the simple act of arbitrarily selecting one among equally obvious alternative variations is devoid of any inventive character. See also T 311/95, T 89/16.

In T 816/16 the board held that the further addition of components well-known for their activity in the technical field concerned was considered an arbitrary choice among components which the skilled person would have had at their disposal. 

In T 1779/19 the proposed solution did not successfully solve the problem presented in the patent. However, the board considered that the experiments in the patent at least demonstrated that the claimed method performed significantly better than other known alternatives. This implied that the claimed additives had been identified as particularly effective for the purpose of preventing chlorine deposition, so they could not be considered to be arbitrarily selected. The board concluded that the claimed subject-matter did not simply provide a (general or arbitrary) alternative, but rather an alternative which was highly effective when compared to other commonly used additives. The problem to be solved was therefore reformulated as the provision of an alternative method which ensured a high effectiveness in the prevention of chlorine deposition.