Here's something I found recently on the internet: "What do you call a person who hypothesises about an unseen intelligent being and searches outer space for confirming material evidence?" Answer: a scientist. And: "What do you call a person who hypothesises about an unseen intelligent being and searches inner space for confirming material evidence?" Answer: a religious nut.
That gets fairly close to the challenge for those of us who say we are attracted to the theory of "intelligent design", or "ID". Vast sums are spent on the search for extra-terrestrial intelligence on the scientific basis that we will be able to recognise non-random, intelligently-designed signals, should we receive them. But when some scientists claim that the highly improbable, complex and specific genetic information carried deep within the living cell in DNA signals an intelligent source, they are dismissed as religious fanatics.
Intelligent design sets out a very straightforward scientific, but essentially limited, proposition. It claims that the natural world exhibits clear evidence of having been designed, and that such design can only arise from prior intelligence.
It is because science has increasingly revealed the improbable complexity and high specificity of natural and living systems that a growing number of scientists are coming to the conclusion that the best explanation of their origin lies in design. From fields such as engineering and information technology, scientists can elaborate the criteria which distinguish the purely random from the deliberately designed.
Attempts to explain origins without reference to prior intelligence are constantly challenged by awkward questions about where matter and energy came from in the first place, how life arose, whether random mutation and natural selection are capable of building the awesomely complex banks of genetic information required for the perpetuation of living things and, perhaps most puzzling of all, the origin of consciousness which somehow plays out on our neurobiology.
Undoubtedly, the philosophical and religious implications of ID are controversial. But they go beyond what ID proposes. Uncomfortable implications don't negate observations, and it is the hard empirical and scientific data about the complexity of nature which demands an explanation of its origin. Design has to be considered in that context.
So has intelligent design any place in school science? Well, a MORI poll for a BBC Horizon programme in 2006 revealed that more than 40 per cent of the population thought so. But there's a better reason than that. I didn't know about ID in its current form when I taught chemistry in the 1970s and 80s. But I do recall that some pupils, especially at the senior levels, when they studied aspects like atomic and molecular structures, raised questions about their ultimate nature and origin.
This is surely a legitimate starting point for discussing the evidential basis for, and the limitations of, scientific theories - including the possibility that atomic systems are designed. It is, after all, the science which poses the questions. And I'm sure biology and physics provide even more scope than chemistry for such discussion.
In the final analysis, the real issue is whether ID is true or not. To deny young people the opportunity to explore that question from a scientific perspective must be contrary to all principles of good education.
As Professor Antony Flew, philosopher and life-long atheist but a recent convert to the case for design, insists, we should follow the evidence where it leads.
Alastair Nobleis field officer for the Headteachers' Association of Scotland, but these are his personal views