The process of natural selection is central to the theory of evolution. Individuals that are somehow less fit to breed are less likely to have their genetics represented in future populations. However, as with life in general, things are not quite that simple. For example, if individuals didn't die then they could represent their own genetics in the future. Why have children at all? Well, one reason is that habitat is limited and there are usually several different species competing for that habitat. Selection not only works within a species, it works between them. With limited habitat, evolution can become a race between species. This race is why we die. Death, like sex, speeds the rate of evolution.
Habitat is finite; populations only have so much space to exist in. When new habitat becomes available, life will fill it very quickly. New habitat can appear either through changes in the environment or in the way a species can use an environment. There are the obvious environmental changes like variations in climate and corresponding sea levels. There are less obvious changes as well. For example, when a species goes extinct, it changes the environment that other species operate in. If one predator in a given environment goes extinct, then there is an evolutionary niche for other predators to evolve into. New environments can also open up when a species evolves ways to utilise resources it could not before. For example, being able to eat a new food, or survive in a different temperature. A salt-water fish that could live in a lower salinity environment would have river estuaries open up to them. Another way a new environment can open up for a species is when barriers to migration are removed. Sea levels could drop enough to allow an island population access to the mainland, or vice-versa. A species could be transported to a new habitat through various means. Whenever new habitat opens up, in whatever way, a competition between species often results. Existing species may be out-competed by a new invading species, or several new species may vie for niches after existing species go extinct. This competition between species makes evolution a race.
An unoccupied environmental niche is easy for a species to evolve into. Even a slight improvement in an individual's ability to exploit this niche provides an advantage that natural selection can favour. With succeeding generations, further slight improvements would also be selected on. However, once a niche is filled by a species, another species would have to evolve a correspondingly better utilisation of the niche. This is very difficult to do when the intermediary steps provide no benefit to be selected for. Species that evolve into a niche first can maintain a permanent advantage. Thus, species that evolve quicker are more likely to expand into new niches and whole new habitats when they open up. The earth is populated by species that won this evolutionary race.
Selection in evolution is either by the individual or by the group. While it is easy to assume group selection is at work, individual selection dominates evolution. The unit of information in genetic evolution is, after all, the gene. However, just as genes work together and share the same fate in an individual, individuals do exist in species and share the fate of the whole. After all, an individual's genetic fitness is moot if there's no one to mate with. When a species goes extinct, by definition, all its individual members are dead. Thus, species are more likely to survive when individuals do things that benefit the species as a whole. Individual genetic lines that do nothing to benefit the species are more likely to go extinct.
Individuals don't evolve, populations do. Each individual's genetic make-up is fixed at conception and this make-up is what is passed to offspring. If an individual has a mutation after conception, positive or not, it is unlikely to be passed onto the next generation. Thus, the variation side of evolution happens at conception. This basic point, that evolution happens at conception, coupled with a limited habitat and inter-species competition to fill said habitat is the reason most life on earth evolved to die. A simple thought-experiment will show why this is.
If we imagine two simplified habitats, each populated by a different species, then the advantages of death become apparent. Each habitat holds a fixed number of individuals; if a new individual is born, it will die unless there is a vacant spot for it to live in. In one habitat, individuals live until they die of accident; in the other habitat, individuals live for a fixed period of time before dying. With the eternal species, creating offspring is risky as death is more likely during pregnancy. When this happens, both the parent and child die while a new space opens up for another individual's child to live in. Thus, having the time to wait for the opportunity to open up, evolution would favour those individuals that held off having children. Reproduction in this environment would be very slow; this slow reproduction means that mutations, and thus evolution, would have limited opportunities to happen. However, in the habitat where individuals die after a fixed period of time, each individual could have offspring with a reasonable chance of living. There would likely be space as other individuals die. The slight chance of dying during pregnancy would be more than offset by the certainty of dying in the end. Thus, the birthrate in each habitat would evolve to match the death rate. However, in the habitat where individuals die at a fixed term, the birthrate would be much, much higher.
The higher the birthrate, the more variations through mutation will occur for natural selection to act on. The same higher birthrate will also allow those positive variations to spread through the population via sex. These factors, combined, will make evolution happen at a faster rate. Eventually, a mutation will come along that allows an individual great benefit. For example, the ability to live in half the space, thus allowing a doubling of population, and a doubling of the rate of evolution. Eventually, a mutation will come along that allows this species to bridge the gap between habitats resulting in inter-species competition. With one species evolving much faster than the other, the slower one will likely be out-competed and eventually go extinct. Over time, species that live forever will be replaced by species that have evolved a mechanism to die.
From this thought experiment, it is clear that there are advantages at the species level when individuals die after a reasonable period of time. Death allows faster reproduction in a fixed habitat. The higher the reproduction, the higher the chance of positive mutations for natural selection to favour. The more selectable mutations that happen within a given period of time, the faster a species will evolve. The faster a species evolves, the better it will be able to compete against other species for habitat. Species that are less able to compete for habitat are more likely to go extinct. Individual genetic lines in an extinct species are dead. Thus, limited habitat and inter-species competition work together to provide an evolutionary advantage where death will evolve over time.
Death evolved because it allows us to have children. These children benefit our species by helping it adapt to new environmental niches. Our species, and thus our genetic line, continues because of this adaptability. In the great evolutionary race, adaptable children beat eternal life. We are what we are because we die.
2008-06-30
2008-06-19
Arguments From Ignorance
Philosophy categorizes several different types of arguments: one argument type is of logical necessity, arguing from experience is another, as is arguing from authority. Most arguments are pretty easy to identify. "This person is an expert in the field and she says X, so X must be true" is an argument from authority. The expert may have a different argument: "Under these circumstances, I've seen X and only X happen," which is an argument from experience. Unfortunately, there is another type of argument that people like to use, an argument from ignorance.
I'll start with a non-religious example. In a magazine article that shall remain nameless, an expert in materials engineering who also happened to be an Egypt buff wrote about his research into obelisk carving. He found a written record stating that a particular obelisk was being carved for a period of time but then the obelisk cracked and the project was abandoned. He then located this abandoned obelisk and noted how much of it had already been carved. Using his considerable skills in materials engineering and after conducting field-tests on rate-of-removal speeds with the tools ancient Egyptians were known to use, he determined that there was no way they could have removed the amount of rock they did in the available time. It was impossible. Thus, he concludes, aliens must have helped the Egyptians.
On the surface, this appears to be an argument from authority, but it is really an argument from ignorance. One other little story may help show this. A person I know grew up in a family that worked with rock. He was learning how to build rock walls, and the like, from his father, who learned from his father, and so on for generations. On the job-site, he watched as workers pounded away on rocks for hours, trying to get them into the right shape for the job at hand, while his father would pick up a rock, look at it, whack it once or twice, and the rock would split apart leaving the necessary shape behind. Because of this skill, his father could do the work of several other men on the job. There are many, many books on geology and working with stone, but the skills his father had to understand rock and work with its internal fault-lines is not something that's in a book. Even if it were written down, it's not something a person could learn by reading. It takes years and years of experience.
So, back to the Egypt example, we have an expert faced with two possibilities: 1) Ancient Egyptian craftsmen, being at the hight of stone-age culture that spanned all the way back to Homo-Habilis, might have known something about working with rock that he doesn't. Or, 2) Aliens came to earth, made contact with the ancient Egyptians, and instead of helping them with medicine, mathematics, or even weapons, they helped them carve big chunks of rock, which they screwed-up while doing such that the obelisk cracked and they had to start over. Given these two options, our expert chose the latter.
This is a typical argument from ignorance. X is impossible, so - insert favourite theory here - must be true; the Egyptians couldn't remove that much stone in the given time, so aliens must have helped. Not only is this type of argument incredibly arrogant, in stating categorically that something is impossible just because we don't know how, it is also incredibly weak as far as arguments go. Anyone wanting to counter this argument merely has to, in an argument from experience, list off the thousands of examples where ignorant people had concluded that gods were doing something, only to be proven wrong by science. There are flashes of lights and booming sounds coming from the sky; I don't know how that happens so the gods must be angry. I don't know why the sun disappeared in the middle of the day, so the gods must be giving us an omen. I don't know why it rains, so the gods must make it rain. The list is very, very long. Experience shows that while we may not know how something happens, it is a bad bet to assume that gods or aliens did it. It is far better to just say: we don't know how X happens, yet, but we'll probably figure it out at some point down the road.
Science often makes mistakes but it is also a self-correcting endeavor. When faced with one of these arguments from ignorance, a scientist will attempt to come up with alternative solutions. Things don't fall down because a god pulls them down, they fall down because of a predictable force called gravity. When one of these hypothesis gains widespread approval, it becomes a theory and, being the most likely solution, is the one taught to new students of science and used for explaining things to non-scientists. However, if enough proof comes along that the theory is incorrect, or incomplete, then it can change. The original theory of gravity has been somewhat replaced or augmented with the theory of relativity, which is being augmented even today. The theory of relativity also happens to be one of the most tested theories in all of science. Yet, someday, it too may be replaced with something better. As such, there are always competing hypothesis that are trying to replace accepted theories. That's how science works.
The evolution of species is a widely-accepted theory. It is what is taught in science class and is what is used to explain things to non-scientists. Life is a very complicated thing and this theory is not a complete explanation; there are things that remain unknown. Further, there are many competing hypothesis covering a myriad different aspects of the overall theory. Some scientists maintain RNA based origins to life while others suggest a more simple chemical synthesis route, for example. However, this ignorance does not mean that God did it; dissent within the scientific community does not mean that we know nothing.
People make arguments along the lines of: X is the mainstream scientific theory to explain Y. Scientists have shown an element of X to be impossible. Thus, X is impossible, so God did Y. By now, you should be able to recognise this as a classic argument from ignorance. While an element of X may bring its validity into question and leave us in a more ignorant position on Y, that just means that we simply don't know everything yet. Experience shows us that arguments from ignorance are useless; just because we don't know how something happens, it does not follow that gods of aliens did it. It just proves that we don't know everything yet.
I'll start with a non-religious example. In a magazine article that shall remain nameless, an expert in materials engineering who also happened to be an Egypt buff wrote about his research into obelisk carving. He found a written record stating that a particular obelisk was being carved for a period of time but then the obelisk cracked and the project was abandoned. He then located this abandoned obelisk and noted how much of it had already been carved. Using his considerable skills in materials engineering and after conducting field-tests on rate-of-removal speeds with the tools ancient Egyptians were known to use, he determined that there was no way they could have removed the amount of rock they did in the available time. It was impossible. Thus, he concludes, aliens must have helped the Egyptians.
On the surface, this appears to be an argument from authority, but it is really an argument from ignorance. One other little story may help show this. A person I know grew up in a family that worked with rock. He was learning how to build rock walls, and the like, from his father, who learned from his father, and so on for generations. On the job-site, he watched as workers pounded away on rocks for hours, trying to get them into the right shape for the job at hand, while his father would pick up a rock, look at it, whack it once or twice, and the rock would split apart leaving the necessary shape behind. Because of this skill, his father could do the work of several other men on the job. There are many, many books on geology and working with stone, but the skills his father had to understand rock and work with its internal fault-lines is not something that's in a book. Even if it were written down, it's not something a person could learn by reading. It takes years and years of experience.
So, back to the Egypt example, we have an expert faced with two possibilities: 1) Ancient Egyptian craftsmen, being at the hight of stone-age culture that spanned all the way back to Homo-Habilis, might have known something about working with rock that he doesn't. Or, 2) Aliens came to earth, made contact with the ancient Egyptians, and instead of helping them with medicine, mathematics, or even weapons, they helped them carve big chunks of rock, which they screwed-up while doing such that the obelisk cracked and they had to start over. Given these two options, our expert chose the latter.
This is a typical argument from ignorance. X is impossible, so - insert favourite theory here - must be true; the Egyptians couldn't remove that much stone in the given time, so aliens must have helped. Not only is this type of argument incredibly arrogant, in stating categorically that something is impossible just because we don't know how, it is also incredibly weak as far as arguments go. Anyone wanting to counter this argument merely has to, in an argument from experience, list off the thousands of examples where ignorant people had concluded that gods were doing something, only to be proven wrong by science. There are flashes of lights and booming sounds coming from the sky; I don't know how that happens so the gods must be angry. I don't know why the sun disappeared in the middle of the day, so the gods must be giving us an omen. I don't know why it rains, so the gods must make it rain. The list is very, very long. Experience shows that while we may not know how something happens, it is a bad bet to assume that gods or aliens did it. It is far better to just say: we don't know how X happens, yet, but we'll probably figure it out at some point down the road.
Science often makes mistakes but it is also a self-correcting endeavor. When faced with one of these arguments from ignorance, a scientist will attempt to come up with alternative solutions. Things don't fall down because a god pulls them down, they fall down because of a predictable force called gravity. When one of these hypothesis gains widespread approval, it becomes a theory and, being the most likely solution, is the one taught to new students of science and used for explaining things to non-scientists. However, if enough proof comes along that the theory is incorrect, or incomplete, then it can change. The original theory of gravity has been somewhat replaced or augmented with the theory of relativity, which is being augmented even today. The theory of relativity also happens to be one of the most tested theories in all of science. Yet, someday, it too may be replaced with something better. As such, there are always competing hypothesis that are trying to replace accepted theories. That's how science works.
The evolution of species is a widely-accepted theory. It is what is taught in science class and is what is used to explain things to non-scientists. Life is a very complicated thing and this theory is not a complete explanation; there are things that remain unknown. Further, there are many competing hypothesis covering a myriad different aspects of the overall theory. Some scientists maintain RNA based origins to life while others suggest a more simple chemical synthesis route, for example. However, this ignorance does not mean that God did it; dissent within the scientific community does not mean that we know nothing.
People make arguments along the lines of: X is the mainstream scientific theory to explain Y. Scientists have shown an element of X to be impossible. Thus, X is impossible, so God did Y. By now, you should be able to recognise this as a classic argument from ignorance. While an element of X may bring its validity into question and leave us in a more ignorant position on Y, that just means that we simply don't know everything yet. Experience shows us that arguments from ignorance are useless; just because we don't know how something happens, it does not follow that gods of aliens did it. It just proves that we don't know everything yet.
2008-06-05
Free Will
People have been arguing about gods and religions for a long time. Science, when it evolved from natural philosophy, added a new wrinkle to these age-old arguments, a new possibility, no gods at all. Those early natural philosophers weren't looking to do this; they were looking to see how their gods ran the world, they were looking for God. But, if you think about the modern God, then you will realise that we can never really find God in nature. Doing so would destroy free-will.
If you strip most modern religions to their essence, it basically comes down to: freely choose to worship God and you will receive salvation in the afterlife. The hows and whys of worship and the nature of salvation may vary, but the underlying message is about the same. People have to make the choice to worship. For most of human existence, this has been a choice between gods. Now, with the advent of science, it is a choice between God and a godless natural existence. And yet, so many people are still trying to prove that God exists, even though that proof would then destroy people's ability to chose. After all, if you knew for a fact that God existed, and that failure to worship would result in damnation, then your choice is going to be very biased. It would not be impossible to chose to not worship, and I've made an argument for it here, but it would be a hard choice. Because of this, if God wanted to maintain free choice, He has every reason to make proof of His existence impossible to get.
How would God ensure that there was never any proof of His existence? Well, there are two possibilities: create nature such that all things come into being through natural means, or create natural means along-side all creations. The first method would be the ultimate in a philosopher's God, a God that created the path for all things at the moment of original creation. It would be a single burst of creation where everything follows on its own path without any further meddling. The second method would involve, with each act of creation, creating a second natural path where that creation could also happen without intervention. Some may think this deceitful but it really isn't. God merely creates two alternatives, both worthy of belief: created by God or created by nature. This choice allows free will to happen. While the first possibility, that of a philosopher's God, is more rational, the second does allow for people that maintain the literal truth of holy scripture or traditions.
Thus, we reach a point where science is in the business of discovering the natural processes that led to the world as we observe it. Science attempts to describe nature, without God. Now, for this to happen, it does not matter if we exist in a godless universe, or if God created a universe that operates without further meddling, or if God creates natural processes alongside each act of creation. The result is the same; science is attempting to discover these natural processes. Discovering these natural processes will say nothing about the existence of God; if God exists, He would have created these processes along with everything else.
Nietzsche proclaimed that God is dead. In actuality, it was the birth of true free-will. Humans finally reached a point where they could reasonably consider a world without God. Before, choice was limited to this god or that god. After, the choice became God or no God. Science has given us this choice; it has given us true free-will.
There can be no proof of God's existence; there can be no proof that God does not exist. If scientists look hard enough, they will discover natural processes for every observable phenomenon. We, as individuals, will have to decide if we are going to worship God or not; we will have to make this decision without any proof. Worshiping God takes a leap of faith, an act of free will. How could it be otherwise?
If you strip most modern religions to their essence, it basically comes down to: freely choose to worship God and you will receive salvation in the afterlife. The hows and whys of worship and the nature of salvation may vary, but the underlying message is about the same. People have to make the choice to worship. For most of human existence, this has been a choice between gods. Now, with the advent of science, it is a choice between God and a godless natural existence. And yet, so many people are still trying to prove that God exists, even though that proof would then destroy people's ability to chose. After all, if you knew for a fact that God existed, and that failure to worship would result in damnation, then your choice is going to be very biased. It would not be impossible to chose to not worship, and I've made an argument for it here, but it would be a hard choice. Because of this, if God wanted to maintain free choice, He has every reason to make proof of His existence impossible to get.
How would God ensure that there was never any proof of His existence? Well, there are two possibilities: create nature such that all things come into being through natural means, or create natural means along-side all creations. The first method would be the ultimate in a philosopher's God, a God that created the path for all things at the moment of original creation. It would be a single burst of creation where everything follows on its own path without any further meddling. The second method would involve, with each act of creation, creating a second natural path where that creation could also happen without intervention. Some may think this deceitful but it really isn't. God merely creates two alternatives, both worthy of belief: created by God or created by nature. This choice allows free will to happen. While the first possibility, that of a philosopher's God, is more rational, the second does allow for people that maintain the literal truth of holy scripture or traditions.
Thus, we reach a point where science is in the business of discovering the natural processes that led to the world as we observe it. Science attempts to describe nature, without God. Now, for this to happen, it does not matter if we exist in a godless universe, or if God created a universe that operates without further meddling, or if God creates natural processes alongside each act of creation. The result is the same; science is attempting to discover these natural processes. Discovering these natural processes will say nothing about the existence of God; if God exists, He would have created these processes along with everything else.
Nietzsche proclaimed that God is dead. In actuality, it was the birth of true free-will. Humans finally reached a point where they could reasonably consider a world without God. Before, choice was limited to this god or that god. After, the choice became God or no God. Science has given us this choice; it has given us true free-will.
There can be no proof of God's existence; there can be no proof that God does not exist. If scientists look hard enough, they will discover natural processes for every observable phenomenon. We, as individuals, will have to decide if we are going to worship God or not; we will have to make this decision without any proof. Worshiping God takes a leap of faith, an act of free will. How could it be otherwise?
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