Rules that govern the physical world are wondrous, complex, and forever beyond our complete comprehension. Add to that the mysterious property we recognise as life-force, and the level of complexity increases many-fold. From the smallest observable subatomic particles, to the outer reaches of the Cosmos, every aspect is controlled by a predetermined, hierarchical set of rules. At the lower level, subatomic particles follow their own set of rules which allow them to form atoms of various kinds. Another set of rules dictates how atoms might combine to form molecules, possibly of great complexity. One of the most intriguing structures to be built from these molecules is DNA, an essential component of all living things. And again, DNA chains or chromosomes have a unique set of rules that govern their behaviour. Chromosomes exist within cells, and embryonic cells can continually divide to create the various forms of life we recognise.
Every living cell must be driven by a common set of rules. It makes no difference if the cell is destined to become a dog or a dinosaur, it must still obey the same rules. So, if all cells behave according to the same set of rules, what determines dog or dinosaur? The obvious answer must be that a cell also contains its own unique information, which in turn influences outcomes from the generic rules. One of the most remarkable features of the life-cycle is the way the mechanics of reproduction allow accumulated relevant life experiences to be passed to future generations. This information is stored in DNA sequences. Here we are trying to make the important distinction between Rules that apply equally to all entities of the same type, and Properties or characteristics that only influence outcomes for specific entities.
Every living organism is the product of both the rules that govern life, and many of the properties inherited from the single cell that continually divided to create the organism. Any condition or state that makes a particular entity significantly different from its peers, is considered a Property of that entity. It is not always easy to distinguish between what might be considered a Rule, and what constitutes a Property. Information programmed into DNA chains relates to both individual characteristics and species specifics. As an example, consider a frog born with some psychological abnormality that sets him apart from his peers. DNA instructions have determined that he was going to grow to be a frog. Embedded elsewhere in those instructions could be some indication of psychological problems occurring somewhere along the cell-division process.
Over the last 50 years, biologists have cleverly and convincingly shown how characteristics of various species adapt to their circumstances, and pass on the information to benefit future generations. The way DNA replicates and stores information is central to the whole mechanism of evolution. However, there may be additional ways of passing information from parent to progeny rather than direct inheritance or teaching by example. Perhaps we have assumed there can be no information transfer from mother to child at or before birth, just because we have no explanation of how such a process might work. Instinct is something that many animals, including humans, appear to possess at birth. Is instinct a pattern of behaviour that belongs to a species as a whole, or does it result from collective wisdom passed down from previous generations? It is not clear we currently know the answer to that.
To be consistent with the premise that all things ultimately result from immutable rules, we need to identify which rules apply equally to all forms of life. One of the most obvious influences on life, is death. Even though end-of-life is often a sad experience in the human context, death is an essential part of life. The approximate end-game for each individual of a species, is just as carefully orchestrated as the start of life. One of the most challenging questions for biological science, is why we age, and what are the mechanisms causing us to wear out. Recent biological advances have given some insight into the way DNA chains are continually shortened at each replication ( Telomeres & Immortality ). There is some randomness associated with this shortening process, and obviously some lifespans are longer than others. There are environmental factors that influence this, but there seems to be an underlying constant built into the genes of every living organism that ultimately dictates a certain natural life-expectancy. It is unlikely we will be able to manipulate the rule that drives this shortening process. However, what we do have is the ability to medically interfere with the natural telomere mechanism, and thereby potentially influence life-expectancy.
So why is programmed mortality important in the survival of the species? The obvious answer is that there must be a sustainable balance between the creation of new life, and the phased extinction at the end of each life. In addition, there could also be a more subtle explanation for the phenomena. A requirement for Evolution, with its dependence on Natural Selection, is that there must be a selection available. This selection results from chance mutations that propagate through a species. Mutation also occurs as cells replicate within an organism throughout its lifetime. This mutation is a double-edged sword, and often produces very undesirable outcomes. As a direct consequence of mutation, various forms of cancer can develop as an individual ages. With programmed mortality, and less likelihood of participating in procreation late in life, there is a safety mechanism that reduces the risk of genetic flaws flowing through to the next generation.
There is another mechanism capable of keeping the population of specific species within the bounds of sustainability – Regeneration. This process is rarely found in either plants or animals. Studies of a particular species of jellyfish, Turritopsis Dohrnii, have demonstrated that they have the most amazing ability to return from adulthood to an infant state, under the right conditions ( Turritopsis Dohrnii ). However, if regeneration was common throughout all lifeforms, it would seriously impede the evolution process by limiting the cross-pollination of genes. We might interpret the curious behaviour for this particular type of jellyfish as an aberration that is allowed within the rules that govern all life.
The immutable rules mentioned in the previous chapter, seem to have more relevance to the rules of physics, than to the rules of life. However, this does beg the question as to whether the rules regarding life might also be immutable. The possible outcomes from applying the rules for life seem endless. When we apply the rules of physics, it appears as though the results range from a clearly defined set of atomic structures, through to relatively predictable behaviour at a cosmic level. What is sometimes obscured in our macro view of the world, is that even the laws-of-physics can produce many different outcomes from the application of a single rule. Every rule has an associated probability that a certain outcome will result from certain input conditions. When we drill down below the atomic level into the strange realms of quantum mechanics, there is no requirement that any particular particle has to be either black or white – it could in fact be black AND white at the same time.
We can identify the chemicals and molecules that are essential to life. What we have more difficulty with is deciding where and when the rules associated with life come into effect. At some point after the creation of our universe, atoms combined to create complex molecules containing the blueprint for life – DNA. The cells containing DNA had acquired a momentous property in the evolutionary scheme. We know approximately when, about 3.5 billion years ago, and are coming closer to understanding how. As regards rules, atomic structures that had been governed purely by the laws of Physics, now in some mysterious way obey an additional set of rules that belong to the relatively new branch of science we term "Biology".
Delving deeper for an understanding about which rules might be associated with which entities, we are faced with the same dilemma as when deciding at what point a collection of atoms might eventually become living matter. Stem-cells, almost spontaneously, begin to follow rules related to the role required of them in a specific environment. They seem to develop and grow entirely in response to their situation. It's interesting to examine the mechanisms involved where they follow both the rules that apply to all stem-cells, and also obey an independent set of rules specifying a group dynamic. Indications are that new cells receive instructions in the form of chemical signals from surrounding cells, encouraging them to perform in a role that will be of benefit to the group as a whole ( Stem-Cell Niche ).
At the moment our universe was born, most scientists agree that visible matter consisted mainly of simple atoms like Hydrogen and Helium. Complex atomic structures were formed at a later time during the life-cycle of stars and galaxies. It is extremely unlikely that any complex molecules existed at the time of the Big Bang, and it must be assumed the material defining life has been incubated elsewhere at a later time. Even though the rules pertaining to life existed at the time of the Big Bang, the environment conducive to life was a long way off.
To try and understand this idea of rules pre-existing any circumstances where they might be applied, let's consider a hypothetical analogy. Imagine millions of Lego blocks were poured into a giant mixer. Left for long enough, the plasma of bricks could fall into place and form LegoLand. It is easy to dismiss this outcome as absurd. And yet, we readily accept the idea that planet Earth and all human civilisation has resulted from exploding stars spewing particles into the galactic mixer. When the first Lego bricks were created, the designer could not have envisaged all possibilities resulting from their use. Similarly, the guys who built the giant mixer in our analogy, could not have imagined the device being used to organise Lego bricks into meaningful structures. So if LegoLand was the result of this experiment, there must have been extra input besides just the bricks and mixer. This extra input must be quite independent of the building blocks or the environment.
Continuing with this analogy, let's contemplate what makes the LegoLand result so unbelievable. Comparing the experiment with the functioning of our Universe is grossly unfair for three basic reasons. Atomic particles are closely integrated with the laws-of-physics, almost as if they were originally part of the same design specification. Anything involving Lego bricks must rely on a tiny subset from the laws-of-physics, without benefit of co-working with these laws. Secondly, the experiment is seriously disadvantaged by the fact that it is only being run once, and thus there is no opportunity to modify the original design to cope with unanticipated situations. And thirdly, formation of LegoLand requires something not accessible from an environment composed solely of plastic blocks – Intelligent Life. In engineering terms, there is something magnificent about any design that stands the test of time, and behaves predictably in every possible future scenario. From a human perspective, this is impossible to achieve. Because the laws of physics and the atomic building blocks have remained unchanged for 14 billion years, one could be led to the conclusion that our universe is not the first where these rules have been trialled. Alternatively, maybe the rules existed unchanged for eternity.
Returning to reality, it is hard to build a model for our existence that does not require input from some unseen and unknown source. Our understanding of atomic structures that are fundamental to everything in our physical world, is expanding at an incredible pace. It must be remembered that humans can never extend their role beyond that of observers. We can conduct some pretty amazing experiments within the existing Laws of Physics and Nature, but with the best will in the world, we can never create a giant mixer that 'knows' how to construct LegoLand. Admittedly, some exceedingly convoluted engineering might do the trick, but that would still require physical implementation. In keeping with the theme of this book, we have categorised the mysterious inputs as the Rules for Eternity.
Interplay between the rules for life and the broader set of immutable rules, creates some interesting possibilities as to what form life might take in extreme alien environments. What if the rules-for-life themselves are completely flexible, and the limitations come from mechanical constraints and the laws of physics? Taking examples from our home planet, it does appear that over a very broad range of environmental parameters, life will attempt to establish a foothold. Because we are surrounded by carbon-based life on Earth, is it valid to assume that this must be the only formula for life? Possibly not. Examining the constraints of physics on the life we are familiar with, usually provides a logical explanation for the way a particular life-form is implemented. For giant trees, the tallest living things, gravitational forces dictate that their centre-of-gravity must be situated close to the centreline. Any serious deviation that creates an imbalance will cause the tree to topple.
As another example of how the laws-of-physics greatly influence what form life can take, consider how huge some species of dinosaur had become during their reign. Limitations were imposed on size, not just by how much food there was to eat, but also how much of it they could eat. If they were purely eating machines, surrounded by food, survival would not be driven by how fast they could travel – a small coefficient-of-drag did not play significantly in their design. These massive objects were seriously hampered by inertia. Perhaps they might have been able to grow even larger but were prevented from doing so purely on the grounds of logistics. Their huge bulk could have made them so lethargic that they became increasingly reluctant to make the effort to drag themselves far enough to find a mate – a fatal mistake in the plan for survival of any species. On a different planet, with quite different gravity, dinosaurs could have evolved to be similar shapes, but radically different dimensions.
Of particular interest to us humans is consideration of what might be limiting factors on the survival of our own species. All animals, with the notable exception of man, surrender gracefully to the dictates of nature that have been designed to ultimately benefit the whole planet and all forms of life. Outcomes might seem harsh on an individual basis, and entire species can become extinct to be replaced by new players. However, that is the broader cycle of life that we have been born to, and must accept. Humans have judged themselves to be positioned at the top of the intellectual tree on planet Earth. Note that other species might assess human intelligence somewhat differently, and could have made a collective decision not to openly challenge the claim. With unmatched ability to influence the planet on a large scale, it is understandable that humans might be tempted to believe they can operate outside the laws of nature. As mentioned previously, this is well demonstrated by the human population explosion over the past century. Population density, distribution and diversity have grown beyond the point where outcomes could be controlled by a handful of powerful leaders. There is now a degree of inevitability associated with the fate of humankind, and it certainly incorporates many undesirable components. One rather pessimistic interpretation might be that human civilisation has run its course, and now faces extinction according to the same rules that apply to all species.
Thanks to careful observation over many generations, guidelines for the good health of both individuals and planet Earth have been established. In recent times, science and medicine greatly sped up the trial-and-error learning process. One recurring theme relates to what we eat – looking back as best we can over thousands of years, it seems dietary patterns of old might have produced more healthy individuals than is often the case in some pampered Western societies of today. There should be no surprise here, and the explanation relates to the slow rate of evolution of the human animal. Back when our cave-dwelling ancestors were evolving to suit the food available to them, the basic bio-mechanisms were established. Because changes in lifestyle were extremely slow, there was time for a evolution to keep pace with mild environmental changes. In modern times, diets are changing rapidly and dramatically, and not always for the best. The bio-mechanisms in place today have not really had a chance to adjust, and research often indicates the benefits of returning to dietary habits of the past. One of the most serious threats to human civilisation is the fact that the environment is changing more rapidly than we can adjust via evolution.
It is almost impossible to distinguish between effects from the fundamental rules of life, and those that result from environmental conditions or influences from other life-forms. Various species might compete in the same territory for the same resources; others might be complementary and provide support and new opportunities. There is one function that does appear common to all forms of life – Optimisation. Natural selection that plays a role in evolution, is one of the more obvious forms of optimisation. Once the basic requirements for life are met, as they are here on Earth, there seems to be no restriction on where and when a new species can be created. The form it takes is designed to fit exactly within the resources available. That surely must be the perfect example of optimisation at its best. Virtually every property of plants and animals is subject to optimisation.
As an example, consider what factors influence the average height of humans. Over the last century, average height has increased a little in response to improved nutrition. There were noticeable dips in height related to both world wars, possibly resulting from poorer dietary conditions. Studies have shown that the average height of humans today is slightly less than it was around 150,000 years ago ( Human Evolution ). The rate of increase today is slowing, suggesting there might be an inbuilt limit for the optimal height of man, and that limit was set when Homo sapiens first appeared. It is logical that early humans were optimised as hunters, and being tall meant they were able to run fast. The idea that there might be age-old inbuilt constraints on humans, has quite interesting implications.
As mentioned previously, all living things have an associated average life-span associated with their species. For humans, there has been a steady increase in life-expectancy through the ages. This has come about because of improving conditions, and in more recent times, medical intervention. As our life-expectancy increases, new threats are revealed that did not have enough time to influence the lives of our shorter-lived ancestors. In the past century alone, there have been several challenges to health that have been addressed to a large degree. Firstly, disease and viral infections were tackled by major advances in medical science. Next came the threat posed by cardiovascular issues in the ageing human. Education and lifestyle changes had a significant impact, as well as medical intervention in the more serious cases. Today, the biggest limiting factor on lifespan appears to be Cancer in its various forms. The unanswered question is just how far can we push the average life-span for humans, given that the original optimised design for was drafted long ago.
Referring to human-life as a separate entity is a huge oversimplification. Any individual human is actually teaming with microorganisms that cooperate in a symbiotic relationship with the basic human components. Inside the human body, there is a never-ending battle between the positive elements and the negative. Eventually, the negative elements overwhelm the various defence mechanisms, and life comes to an end. This same battle plays out in all realms of life. So when we refer to the original optimised design for humans, it is important to incorporate the fact that the microorganisms that inhabit humans today, might have evolved to have very different features and functions as when they first became linked with humans.
Application of the rules pertaining to life produces an unimaginably large number of diverse possibilities. However, the possibilities are not infinite. As with all else in existence, the resultant entities still must comply strictly with the constraints imposed by the laws of Physics and Chemistry. So let's examine the broader parameters that drive life-as-we-know-it. One of the fundamental controls for life is temperature-range. Each particular cellular structure or organism has a certain temperature-range for survival. As humans, we are doomed if we stray beyond the bounds of our temperature survival-band – at the low end of the scale we freeze, the other, we fry. Somewhere in between is a comfortable balance where we thrive and multiply.
To a large degree, Earth's atmosphere controls what forms of life can exist on the surface of the planet. It provides a mechanism to supply the essential elements required to sustain life. Chemical composition of the atmosphere is key, but there are also other atmospheric properties that have an influence on life – primarily Pressure and Temperature. External pressure from the surrounding environment determines many of the internal characteristics of animals. Some of the more exotic lifeforms on planet Earth exist deep in the ocean where there are vents through the Earth's crust ( Thermal-Vent Creatures ). As well as the extremes of temperature and pressure, these hardy creatures coped with a toxic chemical environment that would have excluded previously known forms of life. The comfortable existence we enjoyed on the surface of the planet, encouraged the belief that such conditions were essential for all life. These creatures completely rewrote the book on what we imagined would be limitations for life.
One of the more obscure and sometimes overlooked aspects controlling life, is background radiation. If that exceeds a certain critical level, we would cease to exist in the form that we might recognise. There seems to be an influence on life from radiation, both particle and electromagnetic radiation. At this time, the extent of that influence has not been clearly established. One of the more radical suggestions is that perhaps the radiation continually bombarding Earth plays a part in our evolution by causing the mutation of genes. In addition, there are the undesirable effects of home-grown radiation, and these have been well documented.
Up until this point, we have been developing the theory that everything in existence is driven by a predetermined set-of-rules. This concept becomes most challenging when we attempt to examine the origins of complex lifeforms like humans. Humans are intimately woven into the intricate fabric of life, and hence have a special interest in trying to understand the purpose behind the rules, and where these rules might ultimately lead. The rules defining life as-we-know-it affect the full gamut from single-cell beginnings, all the way through to the recognizable human form. Because humans enjoy maximum flexibility and freedom to play in three of the common four-dimensions, they possibly might require many more rules to control their existence. The difficulty here is to determine if there are specific rules for human life which differ from the generic rules that apply to all forms of animal life?
Posing the question another way, “Is there a specific blueprint for humans; for human life?”. In attempting to find an answer, let's imagine a human is composed of basically two parts; the physical-human and the psychological-human. Much of the physical-human can be explained by the generic rules governing evolution for all life. The psychological human is more difficult to wrap in a precise definition, and is related to brain activity and the resulting behaviour. Human behaviour can sometimes be identified in animals, and thus it is not always easy to determine which traits are uniquely human. Emotion is something often seen as a characteristic belonging uniquely to humans. Darwin first raised the issue of animal emotions over a century ago, and it has been a hot topic for debate ever since ( Emotion in Animals ). As medical science discovers ever more detailed information about which parts of the brain are responsible for what function, we may be nearing the point of determining whether animals have emotions or not. If there is evidence that human characteristics, like emotion, can also be found spread among various animal species, it would become increasingly hard to argue that mankind is special and subject to its own set of rules.
In spite of spectacular advances in the biological sciences over the last few decades, many more questions remain than have been answered. As yet unexplained is the formula common to all animal lifeforms – “What rules govern the choice of partners to ensure the survival of the species?”. One of the fundamental rules for life is that different species can originate from a common ancestor, and yet those species remain in a separate reproductive stream with little crosstalk between species. The consequences of not having such a simple rule for separation, would be disastrous. There is another more subtle rule that dictates partners for procreation. To many, the idea of discouraging sex between siblings or close relatives might seem like a man-made rule that has become institutionalised, rather than a more fundamental rule supporting survival of the species. Over time, inbreeding prevents the diffusion of genes that is so essential to healthy evolution. In turn, this can lead to mental illness or deformities that discourage future participation in continuing the bloodline. Somewhere these rules have already been defined and we are just playing along. Thank heavens the rules have been so carefully crafted. Otherwise, chaos would reign.
There is a simple observation when comparing plant and animal life on our planet. Plants have a symmetrical randomness, and their construction results mostly from the need to obey the laws of physics. Take as an example the way that the branches of tall trees are distributed around a vertical axis. Although branches on one side of a tree would rarely mirror branches on the other side, there is nearly always a balance in the way the branches are distributed around the vertical axis. If too many branches formed on one side of the tree, resulting forces on the root system could overwhelm its anchoring ability, and remove the tree from future participation in evolution of its species.
Animals on the other hand, have a very distinguishable external lateral symmetry in their design. Lateral symmetry makes good sense when considering how important balance is to animals with the freedom of movement. Any lopsidedness in an early mutation would have evolved out of a species, purely on the grounds of survival. The real problem arises when we look at the internal design of animals. For organs that consist of two parts or are duplicated, like lungs for example, good design suggests locating these organs around the lateral centre-line. Many organs in animals are one-offs, like the heart for instance. There is no way to fit all these on a centre-line to maintain good symmetry, and therefore there must have been very careful planning on how to fit all these elements within a given structure. Again, taking the heart as an example, this sits exclusively on the left side of the chest in humans, except perhaps for the occasional mutant. And the burning question is, “Why?”.
This question about alternative designs is equally valid and mysterious for all animal-life, not just humans. The template for all animal species has a clear, asymmetric layout for most internal organs. Did natural-selection play a part in deciding the internal organ structure for humans? Given their limited knowledge of anatomy, would it be sensible to speculate that some early cave-dwellers might have been more attractive to sexual partners because of the location of their internal organs? In previous situations we've examined, there is usually a reason for each and every rule-of-nature that we can identify. Could the phenomena described here be an example of a completely arbitrary choice that became a blueprint for all life that followed? Life is bursting forth spontaneously and independently right across planet Earth, and there is not always a tie back to any single ancestor for any particular species. To be consistent with this observation, the rules governing life would need to specify preference for a certain format, even though there may be no identifiable advantage.
To further investigate what might be missing from our picture of mankind's evolution, think about possible alternative designs for man that would not have altered the species in any significant way. For instance, we might have had a heart on our right-side instead of our left, or maybe even two hearts. The laws of evolution dictate that the best choices eventually win out over options less conducive to long-term survival of the species. But what happens when there are options that are absolutely equal in terms of benefit to the species? Would it be reasonable to expect that both alternatives survive and develop in parallel? It is hard to imagine why having a heart on one side of the body would be a better option for survival rather than having one on the other. And yet, there seems no evidence that evolution experimented with these alternatives during the earliest manifestation of mankind. This does seem to offer a subtle challenge to the mainstream theory of evolution which focuses on the selection of options which provide a discernible benefit.
In our quest to try to understand how the system of rules might fit together, we now find it could be necessary to accept there are some rules which are arbitrary, that have no additional benefit one way or the other. Back to the logic behind having the animal heart on a particular side. The basic layout of things anatomical has a common theme throughout most of the animal kingdom. We could believe that all life relates back to a single ancestor. If you accept this theory, then there must also have been parallel experiments that were discarded. Normally we should not expect the rules to give preference or bias to any particular animal blueprint, without there being an associated benefit. Could there be some bias written in the rules? The concept that we will develop a little later on is that all rules have purpose. And yet, here is an example where the rules seem to be enforcing one choice in preference to another, rather than giving equal opportunity to multithreaded, equally-viable solutions.
Another school-of-thought has it that the whole of everything resulted from Intelligent Design. While it is not the intention here to give weight to that idea, it is difficult to dismiss that concept entirely. Whatever understanding we might claim about our origin, two things are hard to dispute: everything has been magnificently designed, and designed intelligently. And the point that differentiates between all interpretations... Who or what was responsible? The conclusion we would hope to make obvious at the end of this book, is that nothing was responsible for creation because there was no actual beginning. We have quite an insignificant role in the grand scheme of things. The playground where this incredible exercise takes place has existed forever, and will continue to exist forever, regardless of whether there might be lifeforms participating in and observing the process or not.
Let us explore the rules that might contain blueprints for life. If we believe there is a blueprint for every possible life-form, then that leads to the conclusion that there is a near-infinite number of blueprints. A more plausible concept is to perhaps deal with a smaller number of blueprints that apply when certain preconditions for life exist. If the blueprint for man as he exists today, was drawn long ago, it might be possible that man could jump the evolution-queue. That might fit well for Creationist Theory supporters. However, the fossil record on Earth does not support that notion. One interesting analogy is to think about the way Science and Technology have developed. Advances-of-the-day draw heavily on preceding discovery and knowledge. For instance, we could not have had mobile-phones before the invention of the transistor and large-scale integration of electronics. We might map that to the grander scheme, and conclude there is a requirement for certain life levels to exist before specific rules can be applied to facilitate the next level of life.
So far, we have covered situations that are governed by rules. It is equally important to investigate areas where there appear to be no rules. Much of human endeavour is devoted to artistic and cultural development. It is hard to argue that the direction of such development is preordained, rather than a free-will application of chance. As an example, let's look at music as an art-form. What constitutes good music, bad music, or just plain noise, is very subjective. Could there be rules built into the human animal that allow it to distinguish music from noise? In physics, most objects have a natural frequency, and it seems humans may have a similar property. If we analyse marching music – there is a particular rhythm and frequency ideally matched to a fast walking pace of the average human. The suggestion here is that, even though we have complete freedom to create music, there could be some quite obscure rules giving bias to cause certain types of music to be more appealing than others. Widespread rejection of avant-garde styles of art suggests that familiarity is paramount, and that familiarity could result from exposure to things in nature that are in turn controlled by rules.
In the broader context of artistic endeavour, it is hard to imagine any influence from some background rules would be detectable against the influences of chance. Because artistry and culture are driven almost entirely by chance, the odds of there being another William Shakespeare pumping out high-quality literature somewhere on one of the trillions of Earth-like planets, is very remote.
Let's project way into the future when our Sun is nearing the end of its life, and temperatures on Earth might require completely different characteristics for carbon-based lifeforms. Thankfully there are several billion years before we need to be overly concerned. There would appear to be two limiting factors regarding rising temperature and life as we know it – Water and Atmosphere. Once they have evaporated from our planet, there seems to be very little chance for carbon-based life to survive. Recent data from Mars missions strongly indicates what our future might be when we lose these two essentials for life. If Earth maintains its current orientation and spin, we might expect there to be some temperate zones that are more conducive to life than others. And these zones would change location on a regular basis. Thus we might expect that animals with the best ability to migrate, would be the most likely to survive. The ocean depths may also provide respite from the searing surface temperatures. Large surface-based creatures would be the first to go. Heat dissipation might become a deciding factor – skinny creatures with large surface-areas in proportion to their volume, have a better chance of staying within the temperature band best suited to Carbon lifeforms.
Planet Earth has existed nearly half as long as our Universe. This has provided ample data for scientists to look back and study results from the many and varied experiments with life. It has also created an excellent opportunity to identify factors common to all forms of life. One remarkable conclusion to be drawn from the evidence so far, is that all life appears to be carbon-based. When dealing with such complete unknowns as the possibilities for extraterrestrial life, it is never a good idea to say 'never'. In predicting such things, we are constrained between “very likely” and “very unlikely”. It would be a reasonable assumption to expect carbon-based life forms similar to those found on Earth, to exist somewhere out in the vast expanses of space. What we can be less certain about, is the possibility of non-carbon-based life because there is nothing here on Earth that gives any hint that such things are credible. Trying to define what separates life from non-life is difficult, but one clue is in the way that Darwinian evolution belongs exclusively to living entities. There is no evolution involved with Chemistry or Physics – the processes that existed billions of years ago are identical to those observed today.
No matter how thoroughly we investigate the origins of life, it is impossible to avoid the chicken-and-egg question. Did the template for life arrive in our solar system the same way heavy atoms were delivered – from beyond? That theory has a significant number of subscribers, and recent data from the Rosetta mission indicates at least some organic material may have originated outside the bounds of planet Earth ( The Rosetta Mission ). Alternatively, pre-existing rules defining where life might be allowed to form could have been just lying in wait for the right conditions. In other words, there was no requirement for the chicken to pre-exist the egg. But there is an unmistakeable message here; the RULES permitting creation of both chicken and egg must have existed long before presenting a paradox for philosophers.
There are as many guesses as to what form life might take in other solar systems, as there are science-fiction writers. One proposition that will likely remain unchallenged is that the possibilities are endless. Life on all the planets, in all the galaxies, is driven by the same rules, so the diversity we see on planet Earth is merely a glimpse of what may happen elsewhere as a result of varying conditions, and chance.
So putting all these factors together really highlights what a delicate balance there is to create exactly the forms of life that we know about. Unfortunately, this does not offer any clues as to the possibilities for life beyond what we might imagine to be the norm. Given that essentially the same circumstances as we have here on Earth might exist in some far-flung corner of the Cosmos, it is interesting to contemplate whether or not the same lifeforms could have evolved. That's where the rules come into play because they exist absolutely uniformly throughout the space and time of our universe. It would be logical to argue that the same circumstances would produce similar outcomes, chaos theory notwithstanding. Given the untold billions of opportunities for life in the universe, it is quite conceivable that this experiment has already been repeated many times. Even given the endless opportunities for life out there, the probability of having exactly the same civilisation as we have today, is quite small. There has been a lot of chance variation in our history that could have led to a very different outcome. If the dinosaurs still roamed the Earth, would humans have the same population distribution as we currently do? Would we even have evolved at all, or would our progenitors have been eaten long before evolution had a chance to perform its party-trick?