Sunday, 17 June 2012

Life, enzymes and big numbers

It is commonly stated that living organisms are made of 20 amino acids, often referred to as the ‘building blocks of life’, as though just a bit of juggling and a few hundred million years of natural selection would have led to the creation by chance of the first living organisms of which we are aware (i.e. bacteria). See also Natural technology: the bacterium. It is like looking at the bricks in New York city and saying that this ‘explains’ the formation and functioning of this great metropolis, with its transportation technology; cyber networks; telephone, water and power systems; gardens, theatres, cinemas, museums, vibrant streets and communities. All that was needed were various kinds of brick and the rest would follow by natural selection and chance.

Just how irrational is such an approach (not to mention literally soul destroying) was calculated in Cosmic Life Force by Sir Fred Hoyle, FRS, and Chandra Wickramasinghe, first published in 1988.

The simplest living systems of which we are aware, and which appeared a few hundred million years after the creation of the planet, consist of these 20 amino acids arranged into about 2000 enzymes, comparable in complexity to the one below. These enzymes perform a complex spectrum of functions and behave in what can only be described as a purposeful way to edit, repair and modify long chains of DNA via messenger RNA as well as perform a host of other functions we are only beginning to understand. Moreover, amino acids have to be put together in special ways to produce other vital components of life such as histones (which have recently proved crucial in epigenetics, because they help govern a gene's expression of protein) and cytochrome-c (used to transport electrons around the cell). Again, each arrangement is exceedingly improbable. If the positions of the amino acids in the enzymes, histones or cytochrome-c  are wrong the system becomes non-viable. (The building block analogy breaks down: normally the brick of a building can be in any position, while the particular amino acid has to be in a specific life-conferring position within the enzyme.)

Using their mathematical prowess they calculate that the probability of the amino acids forming the enzymes alone is one chance in 10 to-the-power-of-40,000 (i.e. 1 with 40,000 zeros – taking up several chapters of a book). To express the probability of the whole cell forming by chance would take volumes of books to write out the zeros involved. There are ‘only’ about 10-to-the-power-of-80 elementary particles in the entire observable universe, which is many, many orders of magnitude less.

The authors compare the probability to that of over 10,000 spectators arriving at a match in a particular pre-specified and significant order (not any old order). It would take 10-to-the-power-of-40,000 games for this to happen by chance (assuming it would happen at all). If the games were held weekly, say, it would take immeasurably longer than the age of the universe (13.3 billion years). This leaves out consideration of the other components of a living cell, all of them essential. For this degree of organisation to arise by chance is not credible. It would have to be guided in some way. The claim of evolution by random processes is described by the authors as ‘an uneasy combination of wishful thinking and dogma’.  (These calculations have not to my knowledge been improved upon since the book was published. Please correct me if you know otherwise.)

Since 1988 attempts have been made to simulate simpler self replicators, which conceivably could evolve into more complex ones, via software; but they all require human intelligence: the operating system and hardware to run the simulation has to be designed in the first place and the simplest self-replicating software models have to be carefully designed. How such systems could organise themselves by natural selection into the observed fossilised living organisms of over 3.5 billions years ago is a question for a magician, not a scientist. All systems in nature consist not of simpler viable, self-standing systems put together: each component system is useless without the rest. It is all or nothing.

The authors of Cosmic Life Force were far from religious (in fact my understanding was that Hoyle was an agnostic or atheist) but their book concludes with these words:

'The general belief that is common to all religions is that the universe, particularly the world of life, was created by a being of incomprehensibly magnified human-type intelligence....the overwhelming majority of humans would have instinctively adopted this point of view in some form, totally and without reservation. In view of the thesis of this book, it would seem to be almost in the nature of our genes to be able to evolve a consciousness of precisely this kind, almost as if we are creatures destined to perceive the truth relating to our origins in an instinctive way.'

Hoyle thought the universe was infinite and eternal, so he could ‘explain’ how life came about somewhere somehow in the universe by chance then got transported here by chance. Then came the Big Bang theory, which overturned his view of the cosmos: it is far from infinite and eternal and in my view such concepts are philosophically and mathematically untenable, being meaningful only in poetic terms (see links below). Therefore the big question stands. From where did life and the cosmos come?

See also
Infinity, eternity and cosmology
Eternity and thermodynamics

author, 2077 AD
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