Despite the famous feats of termite-fishing chimpanzees and hook-crafting crows, Bergson's words from his Creative Evolution remain largely unchallenged (for a good review of the evidence, see Seed & Byrne Reference Seed and Byrne2010; Tomasello & Herrmann Reference Tomasello and Herrmann2010). Even the most highly trained nut crackers could not manage to equal the abilities seen in the earliest hominin stone tool makers (Davidson & McGrew Reference Davidson and McGrew2005; Iriki & Sakura Reference Iriki and Sakura2008). There is more to the notion of Homo faber, however. For it is not the sheer variety and sophistication of human technologies, but rather the profound complexity of our engagement with tools and technologies that matters the most: We humans alone define and shape ourselves by the tools we make and use. Inspired from the work of Bernard Stiegler (Reference Stiegler1998) and André Leroi-Gourhan (1963/1993), I would like to describe human tool use as the prosthetic gesture par excellence (Malafouris Reference Malafouris, Malafouris and Renfrew2010a). This is a species-unique and self-transforming human predisposition that leaves very little space for valid relational comparisons with other animals (or so I wish to suggest).

I understand that those committed to the long-held evolutionary ideal of a cognitive “continuum” between human and nonhuman animals would probably take my previous points as ill-conceived and anti-Darwinian: “The difference in mind between man and the higher animals, great as it is, is certainly one of degree and not of kind” (Darwin Reference Darwin1871, p. 105). But I think that so far as the human entanglement with tools is concerned, Darwin's claim is rather misleading. What must have certainly started as a difference in degree soon became one of kind – that is, a difference that makes a difference. No doubt, the lack of conceptual clarity about the use and meaning of terms such as degree, kind, mind, and tool is a major contributing factor for our troubles with the question of “human cognitive autapomorphies” (Suddendorf Reference Suddendorf2008, p. 147), and I am afraid Vaesen's paper does very little to help us clear the ground.

In any case, the interesting question is not whether human and animal tool-using abilities are different, but rather, why they are, and how did they become so different. Where do we start, then? Mainstream approaches to the comparative study of cognition follow two main paths when it comes to answering those questions: The first seeks to explain apparent discontinuities in human mental function as the natural outcome of the human genome, that is, resulting directly from biological adaptations (e.g., the “supermodule” hypothesized by the relational reinterpretation [RR] hypothesis proposed in this journal by Penn et al. Reference Penn, Holyoak and Povinelli2008). The second path seeks to account for the differences between human and nonhuman cognitive abilities by way of language, culture, learning, and the external symbolic representational means that these capacities afford (e.g., Tomasello et al. Reference Tomasello, Carpenter, Call, Behne and Moll2005; Tomasello & Herrmann Reference Tomasello and Herrmann2010). The former path takes us into the realm of biology; the latter into the realm of culture.

Vaesen's approach combines both paths. His thesis is essentially that humans are born with better-equipped neural systems and cognitive machinery, which is sufficient to account for the discontinuity between human and nonhuman animal tool use capacity even in the absence of culture. He then shows how our superiority with respect to the nine cognitive capacities deemed crucial to tool use can also explain why technological accumulation evolved so markedly in humans. In other words, the aim of his study is not to question the barrier between “individual brain power” and “culture,” (sect. 1) but instead to argue that human superiority is reflected at the former biological level as much as it is in the latter sociocultural level: “[h]uman tool use reflects higher social intelligence (indeed), but just as much greater non-social wit” (sect.1, para.2).

Here is, then, the nub of the problem – at least as I see it: Whilst Vaesen's comparative gaze seems squeezed within the artificial boundaries that separate the cultural from the biological realm, the sort of things we call tools stubbornly inhabit the hybrid realm between – that is, the realm where brain, body, and culture conflate, mutually catalyzing and constituting one another (Malafouris Reference Malafouris2008; Reference Malafouris2010b). As a result, Vaesen's account leaves out some of the issues that I believe matter the most. For example, the human total reliance on tools (Schiffer & Miller Reference Schiffer and Miller1999) and their role in what Andy Clark calls “supersizing the mind” (Reference Clark2008), or the possibility that the cognitive discontinuity between us and our closest relatives may be largely the product of the cognitive continuity of human brains, bodies, and tools.

Is there any way out of this? I believe that searching for the neural and cognitive bases of tool use provides useful pointers but cannot in itself explain the unique ways humans and tools bring each other into being – especially when grounded in a strictly “internalist” and “computationalist” view of mind, as is the case of Vaesen's paper. The question of human tool use is not one that can be answered by looking deeper into the human brain; it demands a holistic anthropological stance (in both the philosophical and the cognitive sense). We need to start thinking about human tool use as a transformative constitutive intertwining of neural, bodily, and material recourses, rather than in terms of a pre-specified set of adapted neural structures and cognitive functions (see Malafouris Reference Malafouris, Malafouris and Renfrew2010a; Reference Malafouris2010b; Wheeler & Clark Reference Wheeler and Clark2008, p. 3563). This approach to the study of human tool use could also help us to avoid the long-exposed but still engrained anthropocentric prejudices that any discussion of nonhuman animal tool use inevitably embodies (Hansell & Ruxton Reference Hansell and Ruxton2008). Moreover, it will lead us to ask questions not simply about how the mind shapes the tool, but also about how the tool shapes the mind.