One of the greatest mysteries of biology is how we and every other living thing take geometric shape. Modern scientists mostly understand how we have blue eyes or grow to six-foot-one, and even how cells divide. Far more elusive is how these cells know exactly where to place themselves at each stage of the building process so that an arm becomes an arm rather than a leg, and the mechanism which gets these cells to organise and assemble themselves together into what will ultimately be a three-dimensional human form.
The usual scientific explanation has to do with the chemical interactions between molecules and with DNA, the coiled double helix of genetic coding that holds the blueprint of the body's proteins and amino acids. Each DNA helix, or chromosome - and identical 26 pairs are found in each of the thousand million million cells in your body - contains a chain of nucleotides, or bases, of four different components (shortened to A, T, C and G), arranged in a unique order in every living thing.
The most favoured idea is that there is a genetic 'programme' of genes operating collectively to determine shape or, in the view of neo-Darwinists such as Richard Dawkins, that ruthless genes, like Chicago thugs, have the power to create form and that we are 'survival machines' - robot vehicles blindly programmed to preserve the selfish molecules known as genes.
This theory promotes DNA as the Renaissance man of the human body - architect, master builder and central engine room - whose tool for all this amazing activity is a handful of chemicals that make proteins.
Undoubtedly, proteins play a major role in body function. Where the Darwinists fall short is in explaining exactly how DNA knows when to orchestrate this and also how these chemicals, all blindly bumping into each other, can operate more or less simultaneously. Each cell undergoes, on average, some 100,000 chemical reactions per second - a process that repeats itself simultaneously across every cell in the body.
And if all these processes are due to simple chemical collision between molecules, how does it work anywhere near rapidly enough to account for the coherent behaviours that living beings exhibit every minute of their lives?
When a fertilised egg starts to multiply and produce daughter cells, each begins by adopting a structure and function according to its eventual role in the body. Although every daughter cell contains the same chromosomes with the same genetic information, certain types of cells immediately 'know' to use different genetic information to behave differently from others. So certain genes must 'know' that it is their turn to be played, rather than the rest of the pack. This requires nothing less than an ingenious method of communication between cells at a very early stage of the embryo's development, and the same sophistication every moment of our lives.
Geneticists appreciate that cell differentiation depends on cells knowing how to differentiate early on, and then somehow remembering that they are different and passing on this vital piece of information to subsequent generations of cells. At the moment, scientists shrug their shoulders as to how this might all be accomplished, particularly at such a rapid pace.
In other words, like policemen desperate to close a case, scientists have arrested the most likely suspect without bothering with the painstaking process of gathering proof. The details of this absolute certainty - of how proteins might accomplish this task all on their own - are left decidedly imprecise.