 A traditional way for a philosopher of science of looking at this case would be to consider the salient theories and to ask: What evidence compelled scientists to adopt Morgan’s theory? However, this may not be the right question to ask. For this question makes the silent supposition that theories and experimental evidence can be separated from each other in genetics. But it can be argued that the two depend too strongly on each other to be considered separate entities. Classical genetics—in all its forms—was first and foremost a way of doing crossing experiments with various model organisms, and to arrange the results of these experiments in a certain way, for example, linear genetic maps. To be sure, there were also certain ideas about the nature of the gene, some of which highly speculative, others well established by experiments (for example, the linear arrangement on the chromosome, see Weber 1998b). But what is sometimes referred to as “the laws of transmission genetics” or simply “Mendel´s laws” was part and parcel of a certain way of doing genetics. Thus, theory is not separable from experimental practice (Waters 2008). This, of course, cuts both ways: Experimental data in genetics are as “theory-laden” as they are in other sciences, in other words, the analysis and interpretation of experimental data require theories.