William Paley

Writing in 1802, an English clergyman called William Paley imagines himself as a traveller crossing a heath. He stumbles across a pocket watch lying amongst the stones at his feet. He realises how different the watch is from the stones – he can tell from the way it is made, its organisation and its obvious purpose that the watch had a designer and maker.

He sees a link between the watch and the natural world and suggests that many features of nature, particularly of the human body, show similar evidence of a designer. So in his book ‘Natural Theology’ Paley spells out the classic argument for Design in Nature, an argument that has been hotly debated ever since.
When Paley opened the back of his watch he would have seen a complex arrangement of gearwheels large and small, all working together to turn the hands of the watch at precisely the speed required. Whilst he saw similarities between the watch and complex organs like the eye and the ear, he would surely never have believed that nature might contain its own version of the gearwheel. Yet that is what has veryrecently been discovered (published in ’Science’ September 12 2013).

issus coleoptratus

This is the animal: ‘issus coleoptratus’, a small insect 5-6mm long, common throughout Europe. It doesn’t fly, but it is one of the world’s great jumpers, accelerating at nearly 400 g’s (acceleration due to gravity) as it takes off, propelled by its two strong back legs.
It may be helpful to compare the insect’s leg with the more familiar human leg. The human femur has a large bony protrusion at the top just below the ball head that fits into the socket of the hip. This protrusion is called the ‘trochanter’ (in humans there is a ‘greater’ and a ‘lesser’ trochanter) and it acts as the main attachment point for muscles.

bone head showing Trochanter

The insect has a similar arrangement, but at the top of the insect’s femur part of the trochanter widens out into a flat disc. These two discs (one for the right leg and the other for the left) are large enough to touch each other. Where they touch they interlock with a series of small teeth or cogs around the edge of the disc (see scanning electron micrograph below). This means that the two back legs do not always move independently but can be locked together.

The purpose of the arrangement is to make sure that when ’issus’ takes a huge leap, both legs ‘trigger’ at exactly the same time, otherwise the unfortunate bug might spin uncontrollably in the air. Each leg has its own set of muscles, but the electrical signals that trigger the jump are not precise enough to ensure absolutely simultaneous motion at very high speed – hence the ‘gearwheels’ to synchronise the movement of the two legs.

natural gearwheel closeup

The ‘teeth’ are quite different in shape to the human-engineered version. They have a wave-like or ‘shark fin’ profile, and are special in two ways:

1. they are very, very small (see the dimension in microns on the right – a micron is 1/1000 mm).
2. they operate at an incredibly high speed – a short burst at almost 50,000 teeth per second.
By any definition this arrangement is a ‘machine’ – interrelated components working together to acheive a particular objective, synchronous movement. Did this machine have a designer, or did it originate from a process of evolution?

Can evolution produce machines?

In 1949 J.B.S. Haldane, a famous British evolutionist, claimed that evolution could never produce ”various mechanisms, such as the wheel and the magnet, which would be useless till fairly perfect”. Leaving aside what he meant by ‘fairly perfect’(!), presumably he felt on safe ground, as at the time no such machines were known to exist in nature.

diagram of flagellum mechanism

As science has probed deeper, the picture has changed. Nature does have machines. The best known example is the motor that drives the flagellum (the whip-like tail/propeller) of a bacteria, a fast spinning rotor that contains all the finely tuned components that we would expect from an engineer. As for the magnets ref-erred to by Haldane, a number of examples are now known of animals that use magnetic sensors to navigate, including turtles, monarch butterflies and bacteria.

Haldane recognised the enormous problems of explaining how such precise mechanisms, including a number of separate components all working together, could originate from a chance evolutionary process of trial and error – and in 1949 he knew nothing about the information requirements of such systems.

The subminiature gearwheels in this tiny planthopper illustrate the problems involved. You need two separate components (the trochanter), identical except that one is right-handed and the other left. The shape and strength of the teeth need to be sufficient to transfer the necessary energy but with minimal friction; the two sets of teeth need to be perfectly formed and spaced to mesh together without jamming up; the ‘pivot’ of each wheel needs to be accurately placed to achieve rotation without eccentricity; and so on.

Can you imagine the problems of constructing such a machine by trial and error, using only the random changes (‘mutations’) supposedly provided by the evolutionary process, and with no blueprint, no conception of what the actual role of this mechanism is? And each step towards the finished machine needs to work well enough to confer some significent advantage on that particular insect, so that it can be perpetuated on the ‘survival of the fittest’ principle.

These cogwheels have not been carefully machined from inert material like brass or steel or nylon. They are built from living cells, able to grow, repair and rebuild themselves. Every time that ‘issus’ molts, it sheds and rebuilds this mechanism. How does it know how to do that? Because every cell of its body contains the blueprint in the code of its DNA, and each cell has the tools needed to read and interpret that code and build on its instructions.

Is it rational to believe all this happened by accident, without plan, without purpose, without intelligence? Like William Paley’s pocket watch, ‘issus coleoptratus’ shows every evidence of having been put together by a highly intelligent engineer.

…so who invented the gearwheel?

Whatever the textbooks may say, it wasn’t the ancient Greeks – ‘issus’ was hopping around long before them.
So was it Darwinian evolution? or was it the great Creator, the supreme Intelligence and Designer of all things?
What do you think?