An important requirement for a patentable invention concerns inventiveness (also known as ‘inventive step’), which is defined in the law as something that is ‘non-obvious’. This is an abstract concept. For an average skilled person, who is said to be familiar with ‘all’ known techniques in their field (i.e. an illusory person), the invention must not be ‘obvious’.

An argument for inventive step is, for example, obtaining an unexpected or surprising effect. Furthermore, solving a problem that has required a solution for a long time already could be patentable precisely for that reason. Often, arguments can be found that lead the granting authority to grant a patent on an invention that the technician (afterwards) believes is no more than ‘just’ applying the technique. However, it should be noted that many things only seen logical afterwards. A good patent expert will often successfully use the right arguments in order to obtain a patent on relatively small improvements.