5 Hands and Tools

What did the freed hands do for us once we descended from the trees? We no longer needed them full-time for climbing, clinging, and brachiating, so we could use them for other purposes—but what? Carrying babies, making fists, fighting, and scratching itches: but this they were presumably doing already. By themselves they offered little radical advance, and merely dangled. Tool use is the answer. It may be that some tool use already existed in the trees, as it now exists in other primates, but the stage was now set for a great expansion of this activity. Hands turned seriously to tools. Gripping branches would naturally lead to primitive tools, as branches would break and be left in the animal’s grip, ready to be used as clubs, say. Even unbroken, the branch is functioning as a tool for the animal—an instrument whereby the animal achieves its goals. In any case, as anthropologists have demonstrated, the hands came to be used extensively in the manufacture and employment of tools.¹ The tool replaced the tree as man’s chief object of prehension: he went from gripping one kind of thing to gripping another, both in the service of survival. Or, as we might put it, man resorted to gripping tools, given that his old arboreal habitat was no longer available. His hands were bereft and his survival correspondingly threatened; thus he needed to find other work for these now-idle hands, and to discover new survival tactics.² Thus began the era of man the tool-user (no longer the tree-user). And the hands were the part of the human body with which tools immediately interacted. The “hand-tool nexus” was formed and consolidated.

A huge amount has been discovered about early human tool use, but I will not be concerned to rehearse any of this, interesting though it is; I shall limit myself to some interpretative philosophical remarks. First, how shall we define the notion of a tool? If we define a tool as any part of the environment used by an animal to aid survival, we include far too much: the entire habitat of the animal will count as a tool—trees on which birds perch, food materials, water swum through, air breathed. The Sun will count as a tool, as will gravity and the ground walked on. The OED defines “tool” as “a device or implement, typically hand-held, used to carry out a particular function,” or “a thing used to help perform a job.” The second definition is extremely broad, unless we interpret “job” very narrowly (as in “paid occupation”). The first definition is also very broad, since many objects can be “used to carry out a particular function”; so we need to build something more restrictive into the words “device” or “implement”—we have to take these words to be limited precisely to tools. Isn’t a twig a device for perching on, as far as a bird is concerned? Isn’t a branch an implement for a brachiator to use to move around? A branch is certainly handheld by a gibbon, say. It is not clear whether there is any useful natural kind here. Also, we should not adopt a behaviorist conception of tool use, on which a tool-user is simply a creature that externally operates what is in fact a tool. If a bird perches on a hammer, it is not thereby a tool-user. Nor should we require that the animal make the tool. This is not a necessary condition, because some tools are found, not made. Nor is it sufficient to identify what is special about human tool use. Ants make ant nests, but is this the notion of tool that we need when considering human tool use?

When we consider the human construction of axes and spears and the like, and their subsequent employment, what is it that impresses us in this behavior? It is not merely that these are objects with functions made by man—birds’ nests have functions and are made by birds. What impresses us, surely, are not the material facts by themselves but the cognitive background. It is that a certain kind of thinking lies behind the observable behavior—a certain mode of conceiving the world, and hence altering it. It is not the external behavior of using tools that sets us apart, still less the material form of the tool, but the psychological processes that drive this behavior. It is our tool-using intelligence. Even if these processes never actually eventuated in practical tool using, they would still set us apart from other animals. There is all the difference in the world between operating an implement with this cognitive background and operating an implement without it. My point here is not to deny that other apes genuinely use tools; it is just to say that what is important, in terms of evolutionary advance, is whether they share our cognitive processes. They may share them in rudimentary form, in which case they have the beginnings of what is crucial—the external behavior is not the point. Let me put it this way: a mindless zombie cannot really be a tool-user in any interesting sense, even though externally its behavior may look a lot like ours. To have what early humans had when they made and used tools you have to have a certain kind of mind.³

What, then, is this special cognitive background? I suggest that it has two aspects: creativity and teleological reasoning. Thus a real tool-user, such as early man assuredly was, must be a being capable of creative thought and teleological thought. Birds and ants may build impressive structures that function to aid their survival, but they do not engage in creative teleological thought. This is what makes tool-using early man stand out from such other species. This is what powers his progress toward his final destination. It is not the tools as such but the tool-using state of mind—the internal, not the external. By “creativity” I simply mean the ability to see a new use for a piece of found material or the ability to construct something having a new use. It is not enough to instinctively use a piece of the environment for a certain end—say, a twig as part of a nest. What distinguishes the early human use of tools is ingenuity, the seeing of fresh possibilities, imagining what can be done with an object.⁴ The analogue for birds would be, for example, suddenly stealing human hats to be made into nests, as a result of observing the properties of hats and reasoning that they would make good nests. There has to be an element of invention—not in external tool use as such, but in the kind of “tool cognition” present in early man. There has to be the idea of a creative solution to a felt problem—as in attaching a handle to an axe head to increase percussive power. The mere behavioral use of tools is not the issue; it is what went into producing and using the tool that counts. There has to be what we call “intelligence”—creative problem solving, use of the imagination—not the mere manipulation of foreign objects. If an animal finds a new use for its claws, never envisaged before, showing real ingenuity, then that is the relevant talent. The use of stems by apes as “fishing rods” to extract termites from their nests is the right kind of thing to qualify—a genuinely novel solution to a problem. This is what we can assume early humans to possess, though humans now greatly outclass apes as tool-using animals.⁵

The second aspect, which is connected to the first, is that the animal must be able to engage in systematic means-end reasoning. There is a goal to be achieved and a means is devised to achieve it. This requires having teleological concepts: end, means, working toward an end. A future desirable state is envisaged as such and present action is intentionally directed to achieving that future state. This will typically involve deferred gratification: the thought that the future will be better if we make tools now, even if there are more fun things to do at present. This is a complex and sophisticated mode of reasoning. Thus the creativity must be woven into teleological rationality: being creative about the means to achieve a desired goal. The agent must have the idea of a tool—know what a tool is—and must also grasp the concept of work: she must understand that making tools requires work for achieving future goals. This in turn requires a degree of self-consciousness—thinking about what will be good for me (or us). The agent must grasp the nature of planned action, calculated decision. She must also see the world as a potential repository of tools—that conception must be applied to the world of natural objects. She must have thoughts like: “I can make a tool of this.” She doesn’t just use tools; she thinks tools. She has tool intentionality, tool consciousness, tool being-in-the-world. Her inner psychological being is that of a toolmaker and user. This is the mode of cognition that early humans so clearly display in their construction of tools, and which some apes shows glimmers of today. It is not merely that they use bits of the environment to perform certain functions: that is common in the biological world, and is not particularly impressive or distinctive. But early man thinks in terms of instrumental functions: about what is useful, how to achieve it, the actions to be performed, and the sacrifices that need to be made. He views the world instrumentally, and he is ready and able to employ ingenuity to make better instruments. Tool conceptualization is the important adaptive trait, not merely tool behavior.⁶

Once the tool-using adaptation is in place in rudimentary form, the possibility for brain-tool coevolution emerges, as new tools call for increased brainpower and increased brainpower leads to more sophisticated tools. There will already have existed a dawning tool consciousness in man, because in the trees branches and twigs can be used as tools; but once ground living became entrenched, the selective exigencies intensified. Humans needed more and better tools, because their new environment simply did not yield vital resources so readily as the trees. Tools for hunting, gathering, and scavenging will have conferred an adaptive advantage.⁷ Containers for food carriage would be particularly useful. In addition, the freeing of the hands would have led to an increasingly instrumental view of the hand itself—of what it could be used for. New methods of using the hand were called for by tool use, and hence increased manual ingenuity. The hand may indeed have been the original conceptualized tool, as early humans began to appreciate its instrumental powers—for instance, its utility as a device for carrying things over long distances or as a digging implement for uncovering edible roots. The fingernails themselves provide an excellent prototype for tools designed to score and tear—the ingenious early human just needed to make sharper and more powerful nail-like implements. Once the mind has become tool conscious and tool seeking, everything becomes a potential tool, including parts of the body (consider carrying things balanced on top of the head). The human mind becomes tool saturated, tool obsessed. The world comes to be viewed as one big toolbox. Anthropologists rightly stress the evolutionary importance of human tool use, but I suspect that a lingering behaviorism has made them hesitant to ascribe a rich background of tool psychology to early man; they want to stay “objective.” But, I would insist, what passes through the consciousness of ancient man—what occupies his daily thoughts and dominates his imagination—is as important evolutionarily as what passes physically through his hands. In understanding early humans, as well as our arboreal ape ancestors, we need to try to see the world as they did, which means reconstructing their conceptual scheme—their very mode of consciousness (we could call this phenomenological paleoanthropology). And what we find, as evidenced by their actual tool production, is a blooming tool mentality—the conceptual “instrumentalization” of the world, in effect.⁸

As the brain coevolved with tools, so the hands coevolved with tools. In fact, there was a three-way coevolution: hands, tools, and brains became reciprocally modified by positive feedback loops, as if trying to keep up with each other. A newly invented tool, say a spear, would need a particular design of hand and arm to be used in the most effective way, so that design would be henceforth selected for. But the modified limb needed a new control system in the brain, which led to brain enhancements that fed into further tool invention. New tools need new grips, but new grips lead to new tools, and so on. The human hand thus became ever more precise and versatile, as a variety of tools came into use. The great utility of tools in survival imposed a strong selective pressure on the hand and the brain to coevolve so as to make maximum use of these tools. The hand must match the tool it is gripping and wielding; there has to be an effective hand-object correspondence. The hand then slowly evolved over many thousands of years into a device for devices, a tool for tool use. It became fine-tuned by tools, made in their image.⁹ Polymorphic manual prehension of tools was the key to human survival. Dexterity and versatility of the hands were at an adaptive premium.

With this gradual but momentous modification of the hand came another human modification: greater social cooperation. In the trees, food gathering could be more or less individualistic, but on the ground, where hunting and scavenging became the norm, organizing into groups had survival advantage. You could not expect to best a big cat or a mammoth on your own, or even a gazelle. Thus man had to become more social—he needed to belong to a pack. Tools were woven into this increased socialization: they could be exchanged, shared, allotted, portioned out; and the process of their manufacture would require both teaching and the division of labor. The productive role of the hand would be evident to all, and intraspecific hand competition would inevitably arise. The best-made weapon would go to the one with the most able pair of hands. The best toolmaker would be esteemed for his dexterous hands. The individual with whom to mate would be the one whose hands bring the most to the table. Thus hand pride would emerge, and hand admiration, and hand hierarchy. Social bonds would revolve around tool use and hand skills. At some point the hand was introduced prominently into sexual activity (other primates do not use the hand in this way, apparently, or not much anyway). Grooming with the hand would have its own natural appeal. The uses of the hand would thus range all the way from brute aggression (clubbing others) to tender grooming and stroking. Clearly, having powerful, clever, agile, sensitive hands would have social value, as well as individual value. It became the “survival of the handiest.”¹⁰ Thus we see a constellation of factors evolving in unison: tool use (with tool cognition), hand dexterity, brain enhancement, and social structures. This is quite a rich brew, entrained by our forced descent from the trees, where we could get by with less.

We now have a number of adaptations working furiously together in human evolution: bipedal locomotion, hand centeredness, brain expansion, social organization, tool creation and use, and an underlying cognitive sophistication. Each of these factors operates in conditions of dire necessity, because the descent from the trees was forced and extremely challenging. We had to adapt rapidly to the new habitat, and those ill suited to it would soon be extinguished. Presumably many perished in the years following the descent, so intense was the pressure. The population may have shrunk alarmingly.¹¹ The new adaptations were vital. None of these adaptations can be properly understood except in the context of the others: it is a total package. There is a kind of “holism” at work here. Man perforce became a big-brained, tool-using, hand-oriented, socially adept creative thinker. Tools were his answer to expulsion from the trees, where they had only a limited point, and tools brought many other changes with them. Where once he gripped branches he now gripped spears and axes (equipped with his spanking new enlarged thumb). His hands were the primary organs of adaptation to the challenging new habitat. Thus, we might say, our hands were born in the trees but were educated on the land. We had a preexisting arboreal manual form that became modified into a terrestrial form by incremental steps. In our hand we see the form of the ape’s hand clearly inscribed, but we also see the cumulative effect of innumerable small changes—ancestral preservation plus gradual modification. This is all perfectly intelligible and nonmiraculous. What would be unintelligible would be the suggestion that a species quite devoid of hands would suddenly sprout them to cope with an environmental need. Such a saltationist story is, of course, quite preposterous, and we have no need for it: there is a clear continuity between the ancestral form during our arboreal past and the terrestrial human form that exists today. The tree-climber and brachiator is already using his hands by gripping branches; his descendant employs the same basic hand capacity when grasping a spear. A slight elongation of the thumb, combined with some muscle enhancement at its base, will then enable a wide range of new prehensive skills. No saltation is being contemplated here.

As Darwin says, the liberation of the hands entailed by the bipedal gait is the decisive event in our transition to dedicated tool-users. A quadrupedal gait would not have been consistent with the ascent to a full-time tool-using animal. The shrinkage of forelimbs into arms that dangle from an upright trunk led to a huge expansion of the brain, because the small protrusions called “fingers” became vital to our success as a species. The human arm is not an atrophied leg, as with some bipedal dinosaurs and contemporary kangaroos, but a strategically streamlined adaptation. We have the arm that our hands need. It is the redeployment of the hand in the direction of tools, coupled with hand-driven encephalization, accompanied by hand-mediated socialization, which accounts for the Transition, according to the present Darwin-based theory.

But how does this account for the origins of language? Nothing we have said so far has any obvious bearing on that question. Language emanates from the mouth, does it not, so how can the development of the hands be relevant to that? How do we make the transition from manual tool using, however sophisticated, to vocal language using? How do we get from hands to speech?¹² That is the topic of the next chapter.