 Some evolutionary biologists have strongly advocated an engineering definition of adaptation (e.g., Williams 1966). The basic idea is that it is possible to have evolutionary change result from direct selection favoring a trait without having to consider that changed trait as an adaptation. Consider, for example, Waddington’s (1956) genetic assimilation experiments. How should we interpret the results of Waddington’s experiments in which latent genetic variability was made to express itself phenotypically because of an environmental pressure (Williams 1966: 70–81; see the lucid discussion in Sober 1984: 199–201)? The question is whether the bithorax condition (resulting from direct artificial selection on that trait) should be seen as an adaptive trait, and the engineering adaptationist’s answer is that it should not. Instead, the bithorax condition is seen as “a disruption…of development,” a failure of the organism to respond (Williams 1966: 75–78). Hence, this analysis drives a wedge between the notion of a trait that is a direct product of a selection process and a trait that fits the stronger engineering definition of an adaptation (see Gould &amp; Lewontin 1979; Sober 1984: 201; cf. Dobzhansky  1956).[9]