Consider a Hammer

Figure1: Co-opting a natural object

According to Wikipedia, “A hammer is a tool meant to deliver an impact to an object. The most common uses for hammers are to drive nails, fit parts, forge metal and break apart objects. Hammers are often designed for a specific purpose, and vary in their shape and structure.” Hammers have been shaped by the functions they typically perform. A heavy metal head fixed on a light handle stores kinetic energy before the blow is delivered. The length, cross-section and shape of the handle are ergonomically adapted to human handgrip and typical working conditions. There are functionally motivated differences between, say, a light claw hammer used for driving and removing nails and a heavy-duty sledgehammer used for tearing down walls.

Figure 2: Putting a handle on it

The ancestors of all hammers were natural cobbles used as hammerstones by Palaeolithic humans (as well as earlier hominins). They carried out some of the same functions as modern hammers, albeit less efficiently. There was no handle (its function was played by the user’s arm), and hammerstones used for different purposes had the same general shape, differing mostly in size and weight. Small gradual improvements and  occasional major inventions (a wooden handle, the use of bronze or steel instead of stone) transformed the primitive tool visible in Figure 1 into a more sophisticated version (Figure 2), and finally into a fully streamlined  modern hammer (Figure 3).

Figure 3: Shaped by its functions

Of course a hammer can be used for many other purposes beside pounding nails into things or splitting hard objects. It can serve as a makeshift paperweight, a percussion instrument (as in Penderecki’s De Natura Sonoris No. 2), an improvised weapon, and even as a ritual or ceremonial object – for example, the emblem of a smithing god. Such accidental functions do not normally influence the evolution of hammers. If a type of hammer acquires a historically stable secondary function (e.g. removing nails), you can see the characteristic adaptations (a flattened and rounded claw), copied and perfected by new generations of hammer manufacturers. Ad hoc functions have no such consequences. Nobody modifies the shape of a hammer to make it a better paperweight. Its only when a hammer is regularly recruited for a new task that adaptation begins to shape it in a new way. This may lead to the emergence of highly specialised hammers (such as the judge’s gavel or the doctor’s knee mallet).

The first hammers were not designed by anyone. Our distant ancestors learnt to select naturally formed stones. Then they learnt to improve their shape, fix them on a handle to optimise energy transmission, etc. The functional features of a hammer are those that have been consistently selected for in the past. It’s always possible to use a tool in an unconventional way, but such occasional applications don’t explain why the tool looks the way it does. Some features (for example, the colour of the handle) are free to vary. They are non-adaptive, devoid of functional importance.

I hope you can see how this hammer analogy can be applied to linguistic structures. That’s what will be done in the next post.