I watched an interesting documentary on the BBC last week, entitled "Aliens: The Big Think," about the scientific hunt for extra-terrestrials. It was introduced by the cosmologist, Professor Martin Rees, who, it has to be admitted, bears an uncanny likeness to the popular image we have of little grey men. The programme was an easy to understand summary of the current state of affairs in this imagination-sparking field of scientific exploration which, although ultimately optimistic about our eventual first contact with creatures of a different genesis to our own, did emphasise the very real possibility that we are, in fact, alone.
I am very much of the opinion that if there is no creator other than nature itself then around all the billions of stars in all the billions of galaxies there will only be a very few planets that have been colonised by even the most basic organic life forms. In fact, I would not be surprised if life on earth turned out to be completely unique.
Our planet is ridiculously perfect for life to have evolved on it. All the things necessary for life beyond that which is most basic have come together to make our planet hospitable. The earth orbits the sun within the "Goldilocks" zone and it may well be that this is due to the rogue behaviour of a gas giant during the birth of our solar system and that rocky planets within inner solar systems are rare. The fact that the gas giant, Jupiter is where it is means that the earth has been protected from much bombardment by asteroids, comets and other debris from outer space. The earth colliding with a Mars sized planet near the beginning of its existence, which caused the formation of the moon and gave the earth its molten iron core, was an extremely fortuitous event especially as the moon turned out to be just the right size to prevent the earth developing life destroying wobbles. The plate tectonics system of the earth has given the planet the right sort of volcanism to produce the carbon dioxide that is necessary for life to exist and our hefty magnetic field has stopped our atmosphere from being ripped off and ejected into space by the solar wind. To put it simply, we have been very lucky.
The main reasons for my belief in the rare earth theory are all to do with the history of life on earth being one of massive improbabilities, all of which are rendered blatant by straightforward empirical evidence.
Firstly, we have no evidence to suggest that life began on earth on more than one occasion. All the evidence we do have confirms that all life on earth has descended from a single life form. If life has sprung into existence at other times it has not persisted. Therefore, that life began very early on in the history of our planet (pretty much as soon as the basic elements and conditions needed were first present) would appear to be nothing more than a coincidence and not the proof for the ubiquity of life that many claim it is. If life, given the right circumstances, is all but inevitable or even just more than likely, then there would have been many genesises on the young earth. That there was not makes me pessimistic about the commonplaceness of even just single cell life throughout the universe.
Remains of biotic life have been found in rocks that are four thousand, one hundred million years old. However, it was not until a mere eight hundred million years ago that the first multi-cellular life sprang into being. Again, as far as we are aware this transition from single cell to multi cell happened successfully only once. When you consider the amount of time that elapsed and the massive number of organisms that existed between the first single cell creature and the first multi cell creature it becomes obvious that the chances of the evolution from one to the other are about as close to zero as you can possibly get without it becoming impossible. Therefore, if there is life elsewhere in the universe it is extremely unlikely that it will be multi-cellular.
That first, fortunate organism that went from being one cell to being two cells was the grandmommy of over five billion subsequent species. Yet, of all that vast array of varied and increasingly complex sub-divisions of creaturely existence only one species happened to develop and employ a language capable of describing the complex ideas needed for even the most basic form of what we refer to as civilisation. Furthermore, the path from us being apes with basic stone tools to being apes with laptops has not been a smooth one of gradual, but inevitable evolution. Rather, our genus has progressed in mental ability in sporadic jerks any of which may not have happened. Therefore, when the luck involved in an "intelligent" life form evolving is added to the luck involved in all the other stages of development I have mentioned and the many in-between stages I have not mentioned, it seems to me that the possibility of there being little men or women of any colour or none being out there is zilch plus one nano-something, if that.
However, all my pessimism concerning the existence of extra-terrestrial life is based on our understanding of the mechanics of life, the universe and everything that is currently advocated by most scientists. I personally believe that there may well be an agency at work within the universe that considerably increases the chances for life existing elsewhere, maybe everywhere it is even remotely possible. I am not referring to God/god/gods, although this agency might be part of a divine being or might give rise to the existence of a divine being, or, on the other hand, it might not.
After many years seriously thinking about evolution I have come to two main conclusions. Firstly, Darwin was spot on when he formulated the idea of a tree of life. All living things have evolved from the same single progenitor. Secondly, Darwin was wrong about evolution being powered by natural selection in all but the most local and limited of cases. When thinking about evolution, most people when they try to imagine the number of individual creatures that have lived and died during the history of the earth consider a massive number. I, contrarian that I am, regard a very small number in deed. I just do not believe that there have been enough opportunities for one species of life to have evolved to its present state let alone all the varied species that are alive now or which were alive in the past. It is my sincere and nothing to do with my religion belief that there is something intelligent at work within evolution or something that, although non-sentient, mimics the actions of an interventionist intelligence. A few years ago my thinking would have been dismissed out of hand by all scientists but now it would only be scorned by most. There is a growing realisation that there must be more to evolution than we have so far assumed and there are even some, informed and respectable scientific thinkers who are proposing that something akin to intelligence must be at work in evolution for it to work as well as it does even if that "intelligence" is limited to just learning from past mistakes.
Being free from the shackles of the scientific method I am prepared to "what if" beyond the confines of earth. Playfully, I am presently wondering if there is such a magnitude of individual cells of information in the very fabric of the universe that a universal intelligence (of some sort) has evolved. Are parts of the universe intelligent? Is the whole of the universe intelligent? Is the universe conscious? Is it self-aware? Is it sentient? Did God create the universe? Did the universe create God? How much of everything is down to luck? How much was deliberately created to be as it is?
Is anybody out there?