 Buller’s criticism that evolutionary psychologists assume that evolution is finished for the traits that they are interested in connects worries about the understanding of evolutionary theory with worries about the testing of evolutionary hypotheses. Here is Tooby &amp; Cosmides’ clear statement of the assumption that Buller is worried about: “evolutionary psychologists primarily explore the design of the universal, evolved psychological and neural architecture that we all share by virtue of being human. Evolutionary psychologists are usually less interested in human characteristics that vary due to genetic differences because they recognize that these differences are unlikely to be evolved adaptations central to human nature. Of the three kinds of characteristics that are found in the design of organisms – adaptations, by-products, and noise – traits caused by genetic variants are predominantly evolutionary noise, with little adaptive significance, while complex adaptations are likely to be universal in the species” (Tooby and Cosmides 2005, 39). This line of thinking also captures evolutionary psychologists’ view of human nature: human nature is our collection of universally shared adaptations. (See Downes and Machery 2013 for more discussion of this and other, contrasting biologically based accounts of human nature.) The problem here is that it is false to assume that adaptations cannot be subject to variation. The underlying problem is the constrained notion of adaptation. Adaptations are traits that arise as a result of natural selection and not traits that exhibit design and are universal in a given species (cf. Seger and Stubblefield 1996). As a result, it is quite consistent to argue, as Buller does, that many human traits may still be under selection and yet reasonably be called adaptations. Finally, philosophers of biology have articulated several different types of adaptationism (see e.g. Godfrey-Smith 2001; Lewens 2009; Sober 2000). While some of these types of adaptationism can be reasonably seen placing constraints on how evolutionary research is carried out, Godfrey-Smith’s “explanatory adaptationism” is different in character (Godfrey-Smith 2001). Explanatory adaptationism is the view that apparent design is one of the big questions we face in explaining our natural world and natural selection is the big (and only supportable) answer to such a big question. Explanatory adaptationism is often adopted by those who want to distinguish evolutionary thinking from creationism or intelligent design and is the way evolutionary psychologists often couch their work to distinguish it from their colleagues in the broader social sciences. While explanatory adaptationism does serve to distinguish evolutionary psychology from such markedly different approaches to accounting for design in nature, it does not place many clear constraints on the way in which evolutionary explanations should be sought (cf. Downes 2015). So far these are disagreements that are located in differing views about the nature and scope of evolutionary explanation but they have ramifications in the discussion about hypothesis testing.