360 | 33 PIONEER Of ARTIfICIAl lIfE
But this was about as far as it went. Just what those so-called organizers were was unknown;
how they might be able to produce not merely chemical changes but also novel patterns
and shapes—like the tiger’s stripes and its magnificent muscles and head—was equally
mysterious.
The then-fashionable talk of ‘self-organization’ served more to prohibit reference to Blake’s
immortal hand or eye than to offer specific answers: indeed, that notion was a highly abstract
one. It was understood as the spontaneous emergence (and maintenance) of order out of an ori-
gin that is ordered to a lesser degree—where ‘spontaneous’ meant not magical or supernatural,
but somehow caused by the inner nature of the system itself. However, the ‘order’ and ‘origin’
(not to mention ‘emergence’ and ‘maintenance’) were unspecified. In short, the concept of the
organizer was an optimistic place-marker for a future scientific explanation: a tantalizing we-
know-not-what, working we-know-not-how.
Only two years before his tragic death, Alan Turing’s 1952 paper provided the seed of the
answer. He too could specify no chemicals: instead of unknown ‘organizers’ he spoke of equally
unknown ‘morphogens’ (from the Greek ‘form-originators’), so he didn’t solve the mystery of
the what. However, he did solve (at least in outline) the even greater mystery of the how—‘even
greater’, because if embryologists had discovered that this or that chemical was involved, so
what? How could any chemical possibly generate the amazing changes of form seen in the
developing embryo?
As we shall see, his answer was largely ignored for nearly forty years, and as a result many
highly educated people today have not even heard of it. They have, of course, heard of Turing.
Indeed, as a present-day Thomas Macaulay might put it, ‘every schoolboy knows’ (and every
schoolgirl too) that Turing pioneered the theory of computer science, helped to design the first
computers, outlined the research programme for future artificial intelligence (AI), and offered
a still-provocative challenge (the Turing test) to those who denied that computers could ever
think.^4 These contributions have entered so deeply into our culture that June 2012 saw a host of
centenary meetings, and even a UK postage stamp, celebrating Turing’s work in these areas—
not to mention his history-changing codebreaking in the Second World War. But, as of today,
his work on embryology remains largely unknown outside biological circles.
However, what ‘every schoolboy knows’ changes as the years go by: some items simply fall
by the wayside. Macaulay’s ‘every schoolboy’ was said to know ‘who imprisoned Montezuma,
and who strangled Atahualpa’. Maybe in 1840 they did, but schoolchildren today wouldn’t know
either of those things. (Do you?)
Other items get added to the list. Turing’s developmental biology will have found a place
there long before his bicentenary in 2112, for today it is at last being explored by biologists with
increasing excitement and success. It is being applied at all levels: from genetics and cellular
morphology, via embryology, to adult form—and not least, to neuroscience. The neuroscientist
Jack Cowan, for instance, has remarked on ‘a very close relationship’ between Turing’s the-
oretical ideas and the brain.^5 Turing would have been pleased by this, for in his 1952 paper
he mentioned cerebral self-organization as among the important biological phenomena to be
explained.
Given that biology has replaced physics as the science capturing most of the public atten-
tion (and funding), Turing’s reputation in this context will surely continue to grow. One does
not need to be a biologist to know something about his biology, any more than one needs to
be a physicist to know something about Einstein’s theory of relativity. The main reason why
‘every [future] schoolboy’ will know about Turing’s embryonic embryology is that his question