Sameness is one of the two option in the metaprogram “sorting for sameness or sorting for differences”.

Sameness and similarity: (1) the cruder organ sees much illusory sameness (2) the mind wills sameness, i.e., the subsumption of a sensory impression into an existing series: just as the body assimilates inorganic matter into itself. On the understanding of logic: the will to sameness is the will to power. – the belief that something is thus and thus, the essence of judgement, is the consequence of a will that as far as possible it shall be the same.

Notebook 2, autumn 1886 – autumn 1886 paragraph 90