The previous chapter made reference to the fact that all living things have an average life-span associated with their species. For humans, there has been an overall 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 optimized design for them 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 optimized design for humans, it is important to incorporate the fact that the microorganisms that inhabit humans today, might have evolved to have very different characteristics 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. Most researchers believe that around 150⁰C is the theoretical cut-off point for life. At that temperature proteins fall apart, and biomedical reactions cannot occur – a quirk of the biochemistry that life on Earth, as far as we know, abides by.
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 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 any form that we might recognize. 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 institutionalized, 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 illness or disabilities 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 bilateral symmetry in their design. Bilateral 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 random creativity, there is an exceedingly remote possibility of there being another William Shakespeare pumping out high-quality literature somewhere on one of the trillions of Earth-like planets.
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-based 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 being 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 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 civilization 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?
All things considered, life as we know it is only possible during a minuscule moment between the birth and death of each individual star. It is hard to understand the purpose of expending such a huge amount of effort to create a complex cosmological backdrop solely to support the brief appearance of one particular special species. Developing the theme that the whole purpose to everything within our field of observation is for the benefit of mankind leads one to question the need for such a grandiose scale. If all this was just for man's amusement, it could surely have been done in a more compact way. It would seem completely unnecessary to create totally unbounded opportunities for life in other times and other places, and not take full advantage of those opportunities.