As humans, we create life. And we’re all familiar with the idea of artificial intelligence. But what about artificial life? What is it, and why should we care?
Artificial Life is a recently labelled but truly ancient field in which technology is used to imitate biological life. From the earliest stone and clay figurines, to puppets, through hydraulic and pneumatic creations, on to clockwork, through electrical robots and even to flesh, artificial life has a long history that now also extends into the abstract computational realm.
My own interest is as much in the current examples of this phenomenon as in its earliest examples, a prevailing fascination with not only “life-as-we-know-it”, but “life-as-we-have-interpretted-it”.
Since the very earliest days of humankind, we have represented life using whatever technology was available. This has allowed us to observe the traits of life, even our own, in devices over which we have control.
In this way we have embodied our theories of life’s vital principles in artefacts, and tinkered like any Creator from poetry and fiction.
In short, artificial life is central to our attempts to understand who we are.
In the beginning, there were water-clocks
The ancient Greeks were arguably the first engineers to apply technology of any sophistication to the task of simulating life. They devised some marvellous devices that were operated by falling water and animated by pressurised air.
Their projects were launched by Ctesibius’ enhancement of the clepsydra, a water timer used in ancient law courts.
A basic clepsydra is just a bowl with a little hole at the bottom through which water escapes (see image above). The vessel was filled to the top before an important speech. When the water in the vessel had run out, so had the speaker’s time.
The catch with the clepsydra is that it is only useful as a timer. Why? Because half a clepsydra of water doesn’t run out in half the time of a filled clepsydra since the head of water above the outlet is driving the stream.
A power source and a regulator
Ctesibius modified the basic clepsyrda by channelling the outflow into another, lower, vessel. He then maintained a constant water level in the first, upper vessel (see diagram above).
One way he did this was to fit the upper vessel with an overflow pipe at the top, at the point at which he wanted to maintain the constant level.
As long as the upper vessel is filled to overflowing, the flow rate from its lower outlet will be constant. To measure the time that had elapsed on his water clock, Ctesibius just needed to read off the height of the water as it rose in the lower cylindrical vessel.
He did this by positioning a float in the lower vessel. Affixed to this was a rod that raised a little figurine holding a pointer against an hour scale (see diagram above right).
The First Cuckoo Clock
Ctesibius’s clocks moved little figures, sounded trumpets and let stones fall as counters and percussive strikers. In effect, Ctesibius had made the first cuckoo clocks! From here, Philo of Byzantium took up the reins.
He designed many curious devices based on the same principles. These included various trick wine decanters, such as a maid who dispensed wine when a cup was placed in her hand, then mixed the wine with an amount of water to make it suitable for drinking.
He also created a vessel that supported a metal tree, upon which a cleverly wrought mother bird nested, shielding her chicks from harm.
As water or wine was poured into the vessel, a snake alarmingly rose towards the mother’s brood. When it approached too closely, the mother rose above her family, spread her wings and frightened the snake back into its hole. She then folded her wings and returned to her young.
In the first century AD, the century that saw Mt. Vesuvius smother Pompeii and Herculaneum, Hero of Alexandria continued the tradition of devising animated figurines. His too were powered by falling water and voiced with currents of air.
Hero devised a water basin surrounded by twittering metal birds. Nearby, an owl sat, its back turned. At regular intervals the owl would cast its gaze towards the twittering birds, who would fall silent, until once more the owl turned its back on them and they could resume their twittering.
As with Philo’s snake and birds, the interaction between the artificial creatures of Hero mimics the action and response that is one life’s hallmarks.
Hero also devised two automatic miniature theaters. Each consisted of a solid plinth upon which were positioned little animated figures that mechanically enacted a series of scenes. The theatres were powered internally by a falling weight.
The fall of the weight was regulated by a clepsydra filled with grain. One of these theatres could move on to a large performance stage by itself - rolling from offstage then coming to a halt in the limelight.
It would give an animated performance that included altar fires being lit and extinguished, a dance to Bacchus (the god of wine) with flowers and wine. Automatically generated sound effects enhanced the experience. The contraption would then mysteriously roll its way back off stage.
These activities are as important today as they were 2,000 years ago. By devising these simple simulations of life, the inventor is forced to explicitly consider the behaviours that are important, and to distinguish them from those that aren’t. The processes involved require reflection on life’s important traits, and a thorough understanding of how they can be generated.
But there’s a second purpose and value to studying the formation of the type of ingenious contraptions mentioned above. They remind us that, while technology and great minds can be put to many “practical” uses, they can also bring great joy – reminding us what a pleasure it is to be simply delighted.
This material is based on a free public lecture Alan delivered entitled Artificial Life in the Ancient World. It is one of a series on the History of Science, Technology, Mathematics and Philosophy held at Monash University’s Clayton Campus.