A key thesis in The Wealth of Nations is that exchange is good; it allows for specialisation and hence higher productivity. Adam Smith uses this thesis to discuss at length why cities on a coast or navigable river were richer than those inland. Such cities could trade a lot more because transporting goods over water is much easier than transporting them over land.
This can explain in part why early western civilizations developed around the Mediterranean Sea rather than say, up in the Alps. But what I hadn’t thought about, until I started reading a history of capitalism, was exactly why transporting goods on water was so much easier than transporting them on land.
It’s to do with energy.
The drag of water on a boat is much less than the friction between land and an oxcart. Since this friction increases with mass, a boat allows the movement of much larger loads. To this day, oil supertankers and cruise ships, cargo ships and aircraft carriers all dwarf even the heaviest land vehicles by an order of magnitude.
But whether by land or sea, movement requires energy. On land, the energy is supplied to a cart by a human or pack animal pulling it along. On sea however, a relatively simple technology – the sail – harnesses abundant wind energy, converting it into lateral motion.
No wonder the Phoenicians could build a trading network right around the mediterranean coast before the first millennium BCE.
In fact, every productive process requires energy, in the right form. We can see then why the Industrial Revolution was so revolutionary. The steam engine provided a way to turn heat from any source into mechanical energy. With flywheels, crankshafts, pistons and gears, mechanical processes everywhere could be replaced by steam-powered machines. Coal provided a dense, objectified store of such energy, conveniently available where and when it would be needed, very much unlike the fickle winds.
Then with electrification in the late 19th century, a slew of other processes now had access to a generalised form of energy, readily transportable over long distances through wires – no more whale oil lamps.
And this leads me to a further thought – that human labour has always been the most versatile part of every transformative process. With hands and mind we turn the chemical potential energy in food into an infinite variety of productive activities.
This is a theme Paolo Bacigalupi takes up in his post-environmental disaster novel The Windup Girl, where global biotech companies have monopolised all agricultural production. The characters are constantly aware of calories in and out. An electric light is a sign of decadent luxury, while impoverished workers are made to cycle, winding up special springs that store the energy.
We must remember then, as Kant would want us to, that human beings are always the ends and not the means.