 Consider the example that Schaffner (1993) offers in support of the possibility of reduction: the Mendelian concept of “dominance”. On his account, given classical genes a and b, the property “allele a is dominant (relative to allele b)” can be expressed in molecular terms as follows. Assume that genotype aa yields phenotype A and genotype bb corresponds to phenotype B, while ab yields A (because of dominance). We ascertain that gene a consists of DNA sequence α and gene b consists of DNA sequence β, and that phenotype A is brought about by protein א while phenotype B is brought about by protein ב. This yields the following supposed reduction: