9.19.4 Purposive selection

If, for a particular application of a known process, the skilled person could obviously use a material generally available on the market and suitable for the purpose, and was also highly likely to use it for reasons irrespective of its characteristics, such use should not be considered as inventive on account of those characteristics alone. It stood to reason that if carrying out such a step was itself already obvious for other reasons, the natural choice of the particular means on the market-place was devoid of mental or practical effort, or of "purposive selection", in the absence of anything to the contrary (T 513/90, OJ 1994, 154; see also T 659/00).

No inventive step is entailed in accepting a lower yield likely when using a more readily available raw material (e.g. where industrial hemp is substituted for marijuana (cannabis), the latter being more readily available for legal reasons) (T 636/09).