Introduction: The Story of Milo and James
Let us imagine two twin brothers named Milo and James who live under extremely unusual circumstances. They both live alone on a Pacific island that is so remote that ships virtually never pass by it. We can imagine that when the brothers were very young their rich widowed father took them to this very remote uninhabited island, and paid for construction workers to arrive and construct a very comfortable house. Included in the house and its surrounding land are many luxuries such as electricity, solar panels, a backyard swimming pool, a solar-powered kitchen, rainfall-accumulating vats that help make possible running water inside the house, and also quite a few fishing rods and a fishing pier. We can imagine that the father also arranged for quite a few fruit trees to be planted near the house. Sadly, when the brothers were only four years old their father died while swimming, being ate by a shark who left no trace of his body. But given all the fruit trees near their home and the convenient fishing pier and fishing rods, along with the running water, the brothers were able to survive all by themselves, alone on the very remote island.
Let us imagine Milo and James are now fifty years old, and have no memory at all of their father or the construction of their house (because people rarely remember things happening before age five). Milo has no memory of seeing anyone other than James, and James has no memory of seeing anyone other than Milo. They also do not know of anyone outside of their island, because their father had not yet finished constructing a TV antenna that would have allowed satellite TV reception.
One day Milo and James have a philosophical discussion regarding the origin of their house. It goes like this:
"A house like ours and its surroundings are so convenient that they could not have arisen by chance," says James. "Some mysterious power or powers must have designed them."
"No, we need not believe that," says Milo. "We should believe that our house and its convenient surroundings on our island arose merely because of some very lucky random combination of atoms, without any design being involved."
"That's ridiculous!" says James. "The chance of such luck occurring would be far less than 1 in 1,000,000,000,000,000,000,000,000,000."
"But we should not be surprised that mere chance would allow us to live as we do," says Milo. "For if we did not have a house to keep us safe from cold, rainy nights and typhoons, we would not even be here. Our house was a necessity for our existence."
"Oh really?" says James.
"Yes," says Milo. "We can call this an observer selection effect. All conscious observers would have conditions as lucky as ours, or they would not be living as conscious observers."
Milo has committed a very bad error of reasoning that we may call Milo's Error. There is a reason why Milo's reasoning is utterly fallacious: the fact that observers could have briefly existed under very harsh conditions very much worse than the conditions Milo enjoys, and the chance occurrence of such very harsh but observer-permitting conditions would have been more than a trillion quadrillion quintillion times more likely than the chance occurrence of the conditions that Milo enjoys. So it is very false indeed for Milo to be claiming that under a hypothesis of mere chance he should not be surprised to observe conditions as good as he has. Under a hypothesis of mere chance it would still be fantastically unlikely that Milo would have conditions as good as he has.
For example, there is no reason why an observer on a remote Pacific island would have needed the comfy house that Milo enjoys. Someone could have survived on such an island by sleeping at night in a hole in the ground covered by leafy branches, which would have provided barely adequate protection for years. It would be almost infinitely more likely for mere chance to produce a mere uncomfortable sleeping hole than for mere chance to produce a comfy house. There is also no reason why Milo needs to have the great convenience of fruit trees, fishing rods and a fishing pier on his island, which allow him to obtain food with little effort. He could have survived for years by the laborious method of just going out into the water and catching fish with his bare hands. Also, observers could have survived on the island without the solar power, electricity and running water that Milo enjoys. Rain water could have been obtained by laboriously scraping off water drops from leaves whenever it rained.
Accordingly, Milo's theory very much predicts the wrong thing. Under a theory of random chance effects producing conditions allowing observers, it would be almost infinitely more probable that Milo should find himself in conditions just barely allowing him to survive and live a short life, rather than conditions as good as the comfy conditions he enjoys, which have allowed him to live a long comfortable life.
Cosmic Fine-Tuning, Firing Squads and a Multiverse
Just as Milo and James pondered whether their convenient surroundings could be the product of mere chance, philosophers and other thinkers have pondered whether the natural conditions enjoyed by humans could be the product of mere chance. There are many laws of nature and fundamental constants of nature that seem to be fine-tuned or just right to allow our existence. Using reasoning like that of Milo, some have argued that such things are purely the result of chance. They speculate about some vast collection of universes (called a multiverse), and say that in such a collection at least one universe would allow observers. When someone points out the almost infinite improbability of such luck occurring in any particular random universe, our multiverse reasoners appeal to an "observer selection effect," telling us that we should not be surprised to find ourselves in a universe such as ours, because in only such universes could there be observers.
Such multiverse reasoners have committed a reasoning error very much like that of Milo. To explain why that is so, I must give an explanation like that I used to explain why Milo's reasoning was fallacious. To make such an explanation, it is convenient if I talk about firing squads, an analogy sometimes used by multiverse reasoners.
A multiverse reasoner will sometimes tell us that no one should be surprised if he faces the bullet volleys of a firing squad and survives to find himself in good health, on the grounds that because of an "observer selection effect" all survivors would find such a result. This is clearly an example of Milo's Error. A careful analysis of facing of a firing squad gives us probabilities like this:
Most-likely result of facing a 12-man firing squad of well-trained soldiers armed with rifles
Likelihood of 99.999%
Survival, but with wounds so bad that there will be only seconds or a few minutes until death
A thousand times more likely than the third-most-likely event
Third-most- likely event
Survival, but with wounds that will cause either death within hours or permanent disability or brain damage
Very much more improbable than the second-most-likely result
Survival with no wounds
Very much more improbable than the third-most-likely result
This situation is very much analogous to the situation of Milo and James. It would be thousands or millions of times more likely for chance results from a firing squad to have produced survivors just about to die than survivors who had no wounds. So it is fallacious to say that someone surviving a firing squad without wounds should not be surprised by the results. Similarly it would be trillions of times more likely that mere chance would have produced barely survivable conditions for Milo and James than the comfy conditions they enjoyed.
Moreover, when multiverse reasoners claim that we should expect to find ourselves in a universe like ours, they are committing the same kind of error as Milo's Error and the bad reasoning about firing squads listed above. The reason why is that observers could exist in barely habitable universes not allowing most of the luxuries we enjoy, and such a result would have been trillions of times more likely than observers enjoying results as good as ours.
To help explain this point, let's look at some of the "firing squads" that our universe and our planet have survived, typically getting the best result from facing such "firing squads." In each case I will explain why we luckily got neither the most likely result (one that would have prohibited observers), nor the second-most likely result (one that would have just barely allowed observers), but instead a very comfy third-most-likely or fourth-most-likely result (a result very much more improbable than the second-most-likely result, and vastly more improbable than the first-most-likely result).
"Firing Squad" #1: Matter and Antimatter
"Firing Squad" #2: The Ratio of Positive and Negative Electric Charge
We take for granted a feature of our universe that would be enormously improbable in random universes with electric charges: the electrical neutrality of matter. Electrical neutrality means that the total amount of positive electric charge that we observe on our planet is roughly equal to the total amount of negative charge that we observe on our planet.
Such a balance exists because of two things:
(1) Every proton has an electric charge that is the very precise opposite of the charge on every electron (a fantastically improbable "coincidence" that is unexplained by modern science). This seems very inherently improbable, because each proton has a mass 1836 times greater than the mass of each electron.
(2) The number of protons is about equal to the number of electrons.
The universe would be uninhabitable if there was not the type of balance listed above. The chemical reactions necessary for biochemistry require a rough balance of positive and negative charge in our bodies. Moreover, given that gravitation is a force more than a trillion trillion trillion times weaker than electromagnetism, even a slight imbalance in the ratio of positive charges and negative charges in large astronomical bodies would prevent large bodies like planets and suns from holding together by gravitation.
By far the most likely result from this "firing squad" would be an uninhabitable universe. The second-most-likely result (vastly more likely than the result we got) is one that would have left only a barely habitable universe. In the second-most-likely result there would be a large imbalance of positive and electric charges that might still barely allow observers, but which would be fantastically inconvenient. There would be excesses of electric charges all over the place, meaning people would very, very often die just by stepping on a rock and being killed by its static electricity.
Humans managed to escape this "firing squad" by getting neither the most-likely result nor the second-most-likely result, but a vastly improbable result in which electric charge imbalances kill almost no one.
"Firing Squad" #3: The Strong Nuclear Force and Radioactivity
The two fundamental nuclear forces in our universe are the weak nuclear force (involved in radioactivity) and the strong nuclear force (which holds together the nucleus of an atom). The nucleus of atoms such as carbon consists of neutrons with no charge and protons with a positive charge. All particles with the same charge repel each other, particularly when they are very close together. So if it were not for the strong nuclear force, the nucleus of an atom such as carbon and oxygen could not exist for more than a second; the electromagnetic repulsion of the protons would cause the nucleus to fly apart.
In his book The Accidental Universe physicist Paul Davies says that if the strong nuclear force were 5 percent weaker, the deuteron (a nucleus consisting of a proton and a neutron) could not exist, making it “doubtful if stable, long-lived stars could exist at all.” He also notes that if the strong nuclear force were 2 percent stronger, a nucleus called a diproton (consisting of only two protons and no neutrons) would exist, making it doubtful that “any hydrogen would have survived beyond the hot primeval phase” near the time of the Big Bang (and also causing all kinds of problems for the existence of stars like the sun). It is not just the strength of the strong nuclear force that is very convenient, but also its range. If the force was not so very short-ranged, it would preclude the possibility of the complex carbon molecules needed for life.
If you reduce the strength of the strong nuclear force by a small amount, then very common atoms such as carbon and oxygen would be radioactive, because the strong nuclear force would be weak enough that protons in such atoms would occasionally fly apart from electromagnetic repulsion. If you reduce the strength by a somewhat smaller amount, atoms such as carbon and oxygen could not even exist, because the electromagnetic repulsion of protons would prevent them from ever forming.
Cosmologist Luke Barnes states this in a recent paper:
"If the strong force were a few percent weaker, the deuteron would be unbound (Pochet et al., 1991). The first step in stellar burning would require a three-body reaction to form helium-3. This requires such extreme temperatures and densities that stable stars cannot form: anything big enough to burn is too big to be stable... Weaken the strong force by a few more percent, or increase the strength of electromagnetism, and carbon and all larger elements are unstable (Barrow & Tipler, 1986). The parameters of the standard model must walk a tight-rope in order to form stable nuclei and support stable stars."
The most likely result in a random universe would be either no strong nuclear force, or a strong nuclear force with a strength or range that would prevent the possibility of life. The second most likely result in a random universe would be a strong nuclear force that would just barely allow life or observers to exist, under very harsh circumstances. Either the stability of stars would be greatly less or radioactivity would be vastly more common, so common that bodies would be internally radioactive, which would prevent people from living beyond about 20, and make cancer very many times more common. We survived both the most likely result of this "firing squad," and also the second-most likely result. The result we have is the least likely result, one which allows for biochemistry, and in which radioactivity is almost no problem for humans.
"Firing Squad" #4: Particle Masses and the Fine Structure Constant
"In his book The Particle at the End of the Universe (page 145 to 146), Cal Tech physicist Sean Carroll says the following:
"The size of atoms...is determined by...the mass of the electron. If that mass were less, atoms would be a lot larger. .. If the mass of the electron changed just a little bit, we would have things like 'molecules' and 'chemistry', but the specific rules that we know in the real world would change in important ways...Complicated molecules like DNA or proteins or living cells would be messed up beyond repair. To bring it home: Change the mass of the electron just a little bit, and all life would instantly end."
Besides the luck involved in the electron mass having a suitable value, our universe also had great luck in regard to the neutron mass having a suitable value. Physicist Paul Davies says that if the neutron mass were .998 of its actual value, protons would decay into neutrons, and there would be no atoms at all (The Accidental Universe, page 65). Conversely, if the neutron mass were slightly greater, it would mean there could be no long-lived stars like the sun. Section 4.8 of the paper here discusses many different ways in which life and stable molecules and stable stars require a fine-tuning of particle masses and a fundamental constant called the fine structure constant. That section of the paper justifies these statements:
"Firing Squad" #5: Heavy Elements
After the Big Bang, there was only hydrogen, helium, and a little lithium and beryllium. Scientists tell us that all of the other elements were produced inside of stars or from stellar collisions or stellar explosions. Advanced life requires lots of carbon, oxygen, and nitrogen. Having a civilization requires additional elements such as iron. Iron may also be required for intelligent life to exist on planets. The scientific paper here tells us says "Life-forms that do not require iron are exceedingly rare; indeed, only two are known (Borrelia burgdorferi and Lactobacilli)." The same paper gives us geological reasons for doubting that a planet like Earth could have existed unless there was abundant iron in its core.
Astronomers say that some of the elements originated in stars that did not blow up, and others originated in stars that did blow up in supernova explosions. A universe must meet many requirements to get all the needed elements in abundant amounts. For one thing, there has to be something like the weak nuclear force that exists in our universe, because that is needed for supernova explosions. Another thing needed are just the right nuclear resonances, which have to exist in the right way to assure the abundant production of carbon and oxygen by stars. In this paper scientists conclude, “Thus, even with a minimal change of 0.4% in the strength of the N-N force, carbon-based life appears to be impossible, since all the stars then would produce either almost solely carbon or oxygen, but could not produce both elements.”
Below are the number of protons in the nucleus of different elements:
Hydrogen: 1 proton in nucleus
Helium: 2 protons in nucleus
Lithium: 3 protons in nucleus
Beryllium: 4 protons in nucleus
Boron: 5 protons in nucleus
Carbon: 6 protons in nucleus
Nitrogen: 7 protons in nucleus
Oxygen: 8 protons in nucleus
Phosphorus: 15 protons in nucleus
Iron: 26 protons in nucleus
Copper: 29 protons in nucleus
Gold: 79 protons
The heavier the element, the more requirements there are for its large-scale existence. Scientists can explain the lightest elements (hydrogen, helium, beryllium and lithium) solely by appealing to the Big Bang, although their predictions about the amount of lithium are currently off the mark. To explain the origin of carbon and oxygen, scientists evoke dying low-mass stars. To explain oxygen, scientists also currently appeal to supernova explosions (things that have many dependencies and prerequisites). To explain iron, scientists appeal to both supernova explosions (involving very massive stars), and also exploding white dwarf stars.
Scientists currently lack any credible explanation for the existence of elements such as gold and silver. They are currently trying to explain such elements by imagining the extremely far-fetched hypothesis of colliding neutron stars. Since the estimated number of neutron stars in our galaxy is only about 2000, and since the chance of neutron stars colliding in a galaxy as large as ours is extremely low, this explanation fails to be credible. An alternate theory (imagining something almost as far-fetched) is way off in its predictions of gold and silver abundances, off by about 500%.
There are very many fine-tuned dependencies all over the place when we talk about element abundances. Because of the requirement mentioned above, the most likely outcome from a random universe would be either not enough carbon for life or not enough oxygen for life. The second most-likely outcome would be only enough carbon and oxygen for life to occur only as a very rare fluke on a planet (with few organisms), and not enough iron, copper, and other very heavy elements for a technical computerized civilization such as ours to exist. Instead against all odds we got the least-likely result of a universe in which we pretty much have all the elements a computerized technical civilization needs, in high abundances, and also essentially inexplicable luxuries such as the existence of gold and silver.
"Firing Squad" #6: Dark Energy (aka the Cosmological Constant)
Dark energy (basically the same as the cosmological constant) is one of the great unsolved mysteries of the universe. It's not simply that we don't know enough about it. The mystery is that dark energy in our universe is so very small, even though quantum field theory suggests it should be so vasty larger. Scientists say that quantum uncertainty should cause an ordinary vacuum to be teeming with short-lived, fleeting particles called virtual particles. Those particles should give an ordinary vacuum a very high energy density. When scientists do the calculations, they come up with a number indicating that ordinary space should be filled with a vacuum energy density more than 10100 times greater (more than a million billion trillion quadrillion quintillion sextillion times greater) than the maximum value consistent with astronomical observations (a problem known as the "vacuum catastrophe"). The simplest explanation is that there is some lucky balancing by which negative contributions to the vacuum energy density cancel out positive contributions, resulting in a net value near zero. But such a lucky balancing is incredibly improbable (far more improbable than the chance that all of the money you earned in your life would match to the penny, by coincidence, all the money that some stranger spent during his life).
If dark energy had anything like the density predicted by quantum field theory, life would be impossible, as the space between suns and planets would be so dense that sunlight could not travel through it (and also movement around on a planet would be impossible). Although the issue is poorly studied by cosmologists, we can be all but certain that a lesser but still fairly high dark energy would have left us only a barely habitable universe. The most likely situation by far would be dark energy preventing any observers, and the second-most likely situation would be dark energy causing a universe that was just barely habitable, without luxuries such as abundant biodiversity, long-lived observers and long-lived technical civilizations. We escaped both the most likely and second-most likely results from this "firing squad," and enjoy the luxury of a universe in which dark energy causes zero problems for us.
The Many Luxury Results We Enjoy
Let us consider some ways in which our human and earthly results are vastly better than merely what is needed to have observers. They include the following:
(1) An observer might exist without any planet at all, perhaps arising on some comet or interstellar cloud or harsh moon. But on Earth observers enjoy a beautiful planet to explore.
(2) In a barely habitable universe, an observer might exist as some fluke occurrence, with zero or only a handful of other observers known to him, without any society surrounding him. But on Earth observers have a fascinating society all around them to enjoy.
(3) In a barely habitable universe, each observer might have an incredibly hard and painful life, wracked by problems such as stellar fluctuations, radioactivity, explosions caused by antimatter, and death or painful results caused by excess electric charges. But most people on Earth enjoy comparatively comfortable lives.
(4) In a barely habitable universe, all observers might be immobile, existing as organisms like trees or sponges. This is because the amount of cosmic fine-tuning luck needed for mobile observers is much greater than the amount of luck needed for immobile observers. But on Earth people have the luxury of being able to move around. In fact, nowadays (thanks to the luxury of heavy metals such as iron) people even have the luxury of being able to explore distant lands by using trains or jets.
(5) In a barely habitable universe, conditions might be so harsh that most observers might have either ridiculously short lives or lives that do not last much beyond reproduction. But on our planet very many people live comfortably for sixty years or more after first being a mother or father.
(6) In a barely habitable universe, it would be very unlikely that societies could exist, and if societies did exist, they would be short-lived affairs because of things such as stellar instability which would wipe out any civilization after fifty years or more of its existence. But on Earth we have societies and cultures that last for centuries or thousands of years.
(7) In a barely habitable universe, there would be very low biodiversity on any planet, as the appearance of any new species would be fantastically unlikely. But on Earth we have gloriously extravagant levels of biodiversity, with more than a million animal species for us to use and enjoy. The paper here says, "Planets with Earth-like levels of biodiversity are likely to be very rare," a claim it makes based on only geological and astronomical reasons.
(8) In a barely habitable universe, conditions would be so harsh for life that there would probably be no observers capable of communicating with each other through luxuries such as speech and language.
(9) In a barely habitable universe, conditions would be so harsh that there would probably be no intelligent life at all, but merely very stupid observers (such as fish or reptiles or blob-like organisms) incapable of advanced thought or philosophy.
(10) In a barely habitable universe, it would be very unlikely that there could ever exist advanced civilizations that developed computers and something like the Internet. Harsh conditions would prevent societies from lasting long enough for the development of high technology. Moreover, a lack of metals such as iron and copper would tend to prevent the existence of machines such as computers.
(11) In a barely habitable universe, fundamental constants might vary from spot to spot, so that observers might find themselves in some rare little fluke spot in which the constants allowed habitability, preventing any possibility of taking long journeys. We, on the other hand, have the luxury of being able to travel around a whole habitable planet.
Because of all of these factors, our situation is very much comparable to the situation of Milo and James described in the beginning of this post. We should not commit Milo's Error which I described at this post's beginning. An "observer selection effect" cannot at all explain the luxury results we enjoy, just as an "observer selection effect" cannot explain the luxuries that Milo and James enjoyed. Knowing the luxuries he was blessed by, it was logically right for James to have presumed that design was involved in such blessings; and it is logically right for us to presume something similar about our cosmic blessings.
When multiverse reasoners appeal to an "observer selection effect," they are committing a fallacy of simplistic bifurcation, the error of putting everything into two categories, when more than two categories should be used. Totally failing to consider the category of barely habitable universes that allow only observers with no luxuries like we enjoy, they speak as if a universe must either be a universe like ours or a universe excluding observers. The same fallacy of simplistic bifurcation goes on if someone says, "My child, when you grow up, you'll either be a manual laborer, or the leader of a company."
The diagram below helps to illustrate a much more realistic classification scheme, one involving four categories: uninhabitable universes, barely habitable universes, moderately habitable universes, and luxury-permitting universes like the one we live in.