The first part of Richard Dawkins’ polemical documentary on religion, The Root of All Evil?, has certainly sparked plenty of debate and, not unsurprisingly, brought all manner of believers out in force to tell all the good things that there are about religion.

I’m going to wait until I’ve seen the second part before commenting on the programme itself – apart from noting that there was nothing really to choose in the total wingnut stakes between the scary bearded Islamic convert guy and psychotic fascist preacher guy – but one noticable thing about all the various defences of religion that have been mounted so far is that not one of them puts forward a rational argument for or explanation of the presumed existance of god.

Ok, so the usual comeback is that its a matter of faith – but why?

Why believe in the existance of something for which there is no evidence? Or more to the point, as Dawkins noted, why should we take the idea of believing in god any more seriously than believing in fairies at the bottom of the garden, or unicorns, or Bertrand Russell’s celestial teapot. Why should the concept of god be accorded any more regard that that of the Flying Spaghetti Monster?

I suppose the question I want to pose here is ‘is there a rational basis for the concept of god?’, particularly that of a god that exists in man’s image – or the other way around, I guess, if you believe in such a thing?

What this question is not, necessarily, about is either proving or disproving the existance of god; although it’s not entirely true to say that the latter is impossible, as its often suggested – there are hypothetical cosmological models which, if validated experimentally, would do just that by removing ‘the Big Bang’, and therefore the concept of creation, from our understanding of the nature of the universe. Nor can it, indeed, be said that there aren’t logical means of disproving the existance of god – but I’ll come back to that in a short while.

Rather, taking a leaf out the book of supporters of intelligent design, this poses the question of whether there are rational explanations for the existance of the concept of god which do not rely on theology, belief or divine revelation.

And in fact, such an explanation does exist, has existed for centuries and remains in use today within the realms of chaos theory, and that the concept of self-similarity.

To avoid delving too deeply into what is some seriously shit-kicking maths, its perhaps best to use a practical example to illustrate the nature of self-similarity, the concept of a homunculous.

This may sound absurd, but for a short period at the end of the 17th Century and the beginning of the 18th Century, it was believed by some that sperm cells were, in fact, homunculi, i.e. highly miniaturised but fully formed human beings that would transferred from male to female during sexual intercourse in order to grow in the female’s womb – the proponents of this theory were actually called ‘spermists’.

Now you’re no doubt thinking that this was a thoroughly absurd idea, with hindsight and couple of hundred years of scientific knowledge behind us it certainly seems bizarre that anyone could think that way. But no, there really were spermists and they really did believe that sperm cell were little people – in fact for the time this was rather a utilitarian idea that rather neatly explained the then mystery of conception.

How this belief came about is actually very simple to understand. a t the time scientists were beginning to understand that things could and did exist that were too small to be seen with the naked eye or with the help of the limited magnification capabilities of the optical instruments of the time.

In the absence of evidence as to the nature of the microscopic world, scientist of the time assumed/hypothesised that it must possess self-similarity – i.e. that it would be a microscopic version of the world they saw around them. In the absence of evidence as to the nature of the microscopic world, psychology took over and formed conceptions which mirrored the macroscopic world – the process for this was later explained by George Kelly in formulating his personal constructs theory.

Although the term self-similarity and the concept of chaos theory did not emerge until the late 20th Century, the concept of self-similarity was well known to the scientist of the time, as expressed in the alchemical precept ‘As Above, So Below’ – a concept which underpins not only alchemic, but astrology – where events on Earth (below) are believed to mirror the pattern of the movements of astronomical bodies (above) and homeopathy, where it is usual referred to as the ‘Law of Similars’ or as treating ‘like with like’.

Now the import thing to note about self-similarity is that it cut both ways – just as people are psychologically disposed to conjecture that the microscopic world mirrors the visible world, because in seeking to understand the microscopic they have, according to Kelly, no recourse but to make use of and adapt existing constructs, so they are presupposed to the same pattern of thinking when formulating their ideas about the nature of the universe that exists in scales above beyond the visible confines of the world around them.

In the same way that a rational thought process led to the postulate that sperm cells were, in fact, homunculi so the identical process applied at a universal scale to the concept of one of more deities leads natural them being conceived of in human form, or indeed in any other visible natural form from the world around the person doing the thinking.

This explains why, amongst the may and varied conceptions of god that have existed throughout human history, there has never been, before this lact couple of years, the concept of a god in the form of a flying spaghetti monster, because for our ancestors to have conceived of a god in such a form would have required them to know what spaghetti is – and according to legend, spaghetti was unknown to Europeans until the 13th Century when it was brought back from China by Marco Polo.

Logically, the difference between a homumculous and an anthropomorphic god is simply a matter of scale.

It is , therefore, perfectly possible – even likely – that human beings can conceive of a god who exists in human form not in the absence of evidence of such a god’s existances but irrespective of whether such a god exists or not – which, of course, begs the question as to how those religious groups who are currently pushing for the inclusion of intelligent design in science teaching in the US would react were us atheist to push for such an alternative theory to be included in theology curriculums.

The short-lived idea of the spermists that sperm cells were homumculi has another, rather more interesting consequence for the idea of god.

Of course we know, today, that the spermists were wrong and sperm cells are not homunculi – this we can prove merely by use of a suitable microscope. And you might well imagine that this was, indeed how the spermists ideas were refuted at the time.

And you’d be wrong.

What took the wind out of the spermists sails was not the physical disproof of their ideas by means of evidence, but a logical disproof.

The argument is very simple. If sperm cells are homunculi then they must produce their own sperm cells, which must be even smaller homounculi, and so and so on. Logically it was demostrated that the idea that sperm cells were, in fact, tiny little human beings was logically invalid because it to a reducto ad absurdum – a logical fallacy.

Now, if one takes this idea and applies it to the concept of god, using the principle of self-similarity, one arrives first at the question:

If god created the universe, who created god?

This is a question that run entirely contrary to theological belief but logically, it remains an entirely valid question to which there are only two possible answers.

The theological answer is, of course, no one – god simply exists; but then god must have come into being from nothing and that violates the first law of thermodynamics in its universal form as the law of conservation of energy. So as were seeking rational arguments here, that answer must be excluded.

The only alternative answer is that there must be another self-similar god, on a larger scale, who create the god, who then created the universe – in which case, as with spermism and the homunculous postulate, we arrive at another reducto ad absurdum and a logical disproof of the existance of god.