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Machines Like Us

We are the creators of artificial life – both now and through the ages

Tuesday, 11 September 2012
by Alan Dorin

Limestone sculpture by John Fisher.

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.

Three Greek engineers of note in this regard were Ctesibius of Alexandria (fl. 270 BC), Philo of Byzantium (c. 280 – 220 BC) and Hero of Alexandria (c. 10-70 AD).

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. 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.

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.