Let me make a list of only some of the things a person might carefully consider when judging such probabilities. Every one of these variables or numerical considerations is relevant to the likelihood of life appearing on other planets or the likelihood of intelligent life appearing on other planets, or is relevant to the degree of confidence you should have when estimating such things. I will usually try to briefly mention why such numbers are relevant to the likelihood of life or intelligent life appearing on other planets, although in a few cases I may skip such an explanation for the sake of brevity.
Relevant number 1: The average and median number of amino acids in a protein.
The higher this number is, the harder it is for functional proteins to arise, and the more unlikely that life and intelligent life would arise. The median number of amino acids in a protein molecule has been estimated as 375.
Relevant number 2: The total number of possible amino acids that can exist in any one position in a protein (or in any one spot in the sequence of amino acids corresponding to the protein).
The higher this number is, the more unlikely that there could arise a fine-tuned protein molecule consisting of hundreds of amino acids arranged in just the right way to achieve a particular functional effect. Given how the genetic code works, this number is about 20. When we combine this number with the previous number, we get what is called a combinatorial explosion, meaning a vast number of possible combinations. The total number of ways to arrange the amino acids in an average-sized protein is something like 20 to the 375th power. Only the tiniest fraction of such arrangements would result in a functional protein.
Relevant number 3: The minimum number of types of proteins in the simplest living thing.
The higher this number is, the more unlikely that life could arise by chance. There are reasons for thinking this number must be at least 50, meaning that at least 50 types of complex inventions (each a different type of protein molecule) must occur for life to get started.
Relevant number 4: The total number of types of proteins in an intelligent species such as man.
The higher this number is, the more unlikely that you could ever get life as complex as a human being. The number is more than 20,000.
A good indicator of the complexity and functional intricacy of a cell is the number of protein molecules inside the cell. This has been estimated as being 42 million. The higher this number is, the more complex cells are, and less likely that cells could naturally appear.
Relevant number 4: The total number of types of proteins in an intelligent species such as man.
The higher this number is, the more unlikely that you could ever get life as complex as a human being. The number is more than 20,000.
Relevant number 5: The percentage of protein molecules that have been classified as single-domain proteins.
To try to explain the appearance of so many fine-tuned protein molecules in living organisms, scientists may resort to some kind of "proteins are built from smaller components" idea that claims that a protein molecule arises from smaller parts called protein domains. But many protein molecules are single-domain proteins that cannot be explained as having formed from such smaller parts. The higher the percentage of single-domain proteins, the more unlikely it is that you would end up with species such as man built from so many types of proteins. It has been estimated that 35% of eukayrotic proteins are single-domain proteins, and that 60% of prokaryotic proteins are single-domain proteins.
Relevant number 6: The percentage of protein domains that have been shown to be independently useful components.
There are many claims that protein molecules are built from smaller units called protein domains. But little has been done to show that such protein domains can actually function independently. If this Relevant Number 6 is small enough, protein domains aren't much help in explaining the origin of proteins, and we are left with a "proteins are too hard to form naturally" situation that should reduce estimates of the likelihood of extraterrestrial life and extraterrestrial intelligence.
Relevant number 7: The average size of a protein domain
If proteins can be built from smaller components that are relatively easy to form, that would make the natural appearance organisms such as man easier. But if a protein domain is itself a very hard thing to achieve, all the worse for explaining the appearance of proteins. The scientific paper here states that "the average length of a protein domain is approx. 120 amino acids." So a functional protein domain isn't any easier to randomly form than a fine-tuned functional paragraph consisting of 120 characters.
Relevant number 7: The average size of a protein domain
If proteins can be built from smaller components that are relatively easy to form, that would make the natural appearance organisms such as man easier. But if a protein domain is itself a very hard thing to achieve, all the worse for explaining the appearance of proteins. The scientific paper here states that "the average length of a protein domain is approx. 120 amino acids." So a functional protein domain isn't any easier to randomly form than a fine-tuned functional paragraph consisting of 120 characters.
Relevant number 8: The average number of domains in a protein
If this number is high, such as ten or twenty, the appearance of so many functional proteins would be much easier to explain. Unfortunately, the number is low. A table in this paper gives us an indication of the average number of domains in proteins, and suggests the average number of domains in a protein is only about 1.3.
Relevant number 9: The “average promiscuity” of protein domains
Protein domain "promiscuity" occurs when a single domain is used by more than one protein. If there is evidence for a great deal of protein domain "promiscuity," something like "code re-use," it would make it more likely that there might arise creatures such as humans with so many fine-tuned proteins. But the study here found that only 147 protein domains are used by more than one protein. It also found that when protein domains are promiscuous, they are usually used by only between 1 and 5 different proteins. Similarly, the science textbook here concludes "there are few common folds" in the universe of all proteins.
Many proteins cannot fold correctly by themselves, and require other molecules called chaperone proteins. The higher the percentage of proteins requiring such chaperone proteins, the greater the hard-to-explain interlocking dependencies of molecules, and the less likely that an intelligent species might appear through natural evolution. According to the source here, twenty to thirty percent of protein molecules require chaperone proteins.
Relevant number 11: The probability of a random mutation breaking the functionality of a protein molecule
The higher this number is, the more fragile protein molecules are, and the less likely that some planet could ever evolve an intelligent species such as man. The paper "Protein tolerance to random amino acid change" suggests that a random mutation will have about a 34% chance of breaking the functionality of a protein molecule in which it occurs.
Relevant number 10: The percentage of proteins requiring helper molecules called chaperone proteins
Relevant number 11: The probability of a random mutation breaking the functionality of a protein molecule
The higher this number is, the more fragile protein molecules are, and the less likely that some planet could ever evolve an intelligent species such as man. The paper "Protein tolerance to random amino acid change" suggests that a random mutation will have about a 34% chance of breaking the functionality of a protein molecule in which it occurs.
Relevant number 12: The number of protein molecules in a cell
Relevant number 13: The number of cell types in an organism such as man
The greater this number, the more hard-to-achieve an intelligent organism would be. Humans have about 200 types of cells.
The greater this number, the more hard-to-achieve an intelligent organism would be. Humans have about 200 types of cells.
Relevant number 14: The number of organelles in the most complex cell types
This number is very high, and is constantly misrepresented by deceptive cell diagrams which make it look like a cell has only a few organelles. The higher the number of organelles in a cell, the more the cell is a hard-to-achieve unit unlikely to appear through natural processes.
Relevant number 15: The number of mammalian body plans specified in genomes
If we know that body plans are specified by genomes (DNA), then we might have some idea of how new large-sized organisms might appear (from modifications of DNA). This number is actually zero. DNA only specifies low-level chemical information, not high level structural information such as body plans. The nonexistence of body plans in DNA should make us lose confidence in any estimate of a likelihood of large organisms such as humans appearing elsewhere, since there is no real understanding of how such body plans could appear, contrary to boastful claims about this topic.
Relevant number 16: The number of organs, limbs or appendages specified in genomes
This number is zero. DNA only specifies low-level chemical information, not high level structural information such as how to construct an organ or limb. The nonexistence of such information in DNA should reduce our confidence in any estimate of a likelihood of large organisms such as humans appearing elsewhere, since there is no real understanding of how organs or appendages of such organisms could appear, contrary to smug brags about this topic.
Relevant number 17: The number of cell structures specified in genomes
This number is zero. DNA only specifies low-level chemical information, not high level structural information such as how to construct the incredibly complicated units that are cells. The nonexistence of such information in DNA should reduce our confidence in any estimate of a likelihood of large organisms such as humans appearing, since there is no real understanding of how the roughly 200 cell types required by such organisms could appear, contrary to pretentious boasts about this topic.
Relevant number 18: The number of natural protein molecules or natural genes that have been proven to have originated from random mutations, natural selection, or any combination of the two
Of the total number of different types of protein molecules in the animal kingdom (estimated to be between 10 billion and 10 trillion), how many have been proven to have originated from random mutations, natural selection, or any combination of the two? The answer is zero. This is certainly a relevant number to consider when we are judging the likelihood of large intelligent organisms appearing elsewhere through something like a Darwinian process.
Relevant number 19: The number of living things or functional proteins that have appeared through experiments realistically simulating the early Earth
This is a very important number to consider when judging the chance of life naturally arising elsewhere. If we knew that attempts to simulate the early Earth had producing a living self-reproducing cell, that would give us confidence that such a thing is not too hard. If we knew that attempts to simulate the early Earth had produced at least a functional protein molecule, this be a reason for thinking that maybe the natural origin of life was not too hard. But all such attempts have failed. Neither a living cell nor a functional protein has ever been produced in experiments realistically simulating the early Earth.
Relevant number 20: The number of biologically relevant amino acid types that have been produced through experiments realistically simulating the early Earth
There are twenty types of amino acids used by living things. The fewer the number of amino acid types that can be produced through experiments simulating early Earth conditions, the less likely it would be for there to occur the random appearance of life from such chemical units. The actual number of types of biologically relevant amino acids that have been produced in experiments realistically simulating the early Earth is no greater than one. Of the twenty amino acids used by living things, only glycine has been produced in experiments realistically simulating the early Earth. The famous Miller-Urey experiment that produced some amino acids was not a realistic simulation of the early Earth. Most other experiments producing amino acids do not qualify as realistic simulations of early Earth conditions.
Relevant number 21: The number of amino acid yields with homochirality that that have been produced through experiments realistically simulating the early Earth
In earthly life there is a propery called homochirality, which means that essentially all amino acids in proteins are "left-handed." The origin of this homochirality is a great mystery. No experiments designed to simulate the early Earth have produced any amino acid mixture having such homochirality. This failure is a reason for being pessimistic about the likelihood of the natural origin of life on other planets.
Relevant number 22: The number of nucleosides that have been produced through experiments realistically simulating the early earth
Nucleosides are molecular units that are building blocks of DNA. The fewer the number of nucleosides that can be produced through experiments simulating early Earth conditions, the less likely it would be for there to occur the random appearance of life from such chemical units. Nucleosides have never been produced in experiments realistically simulating the early Earth. You can read here about the failures of such experiments.
Relevant number 23: The total number of stars that have been searched for radio signals from extraterrestrial civilizations
This number is very relevant for any estimate of the likelihood of intelligent life appearing on other planets. If countless millions of stars have been searched unsuccessfully for radio signals, this would seem to reduce the chance that extraterrestrial intelligence is common.
Relevant number 24: The total number of neuroscience observations or case histories raising doubts about claims that intelligence comes from the brain
If there any neuroscience observations or case histories raising doubts that the brain is the source of the human mind or the storage place of human memories, this has a negative effect on any optimistic claims about the odds of intelligent life appearing on other planets; for if we don't understand where our own minds come from, we have no business calculating about the odds of intelligence on other planets. There are many such neuroscience observations and case histories which you can read about at great length at this site. They include observations of people with good minds or sometimes above-average intelligence who had lost most or almost all of their brains due to injury or disease, and observations that synapses consist of proteins with lifetimes far too short to store memories for even a year, let alone the 60 years or more than humans can remember things.
Relevant number 25: The total number of parapsychology observations or case histories raising doubts about claims that intelligence comes from the brain
If there any parapsychology observations or case histories raising doubts that the brain is the source of the human mind or the storage place of human memories, this has a negative effect on any optimistic claims about the odds of intelligent life appearing on other planets; for if we don't understand where our own minds come from, we have no business calculating about the odds of intelligence on other planets. There are many such parapsychology observations and case histories, including innumerable accounts of apparition sightings by reliable observers (with the same appartion often seen by multiple observers), along with countless accounts of people who had near-death experiences when their brains were shut down because of heart stoppage or cardiac arrest (including observations of details that should have been neurally impossible during such brain shutdowns).
Relevant number 26: The number of planets in the habitable zones of sun-like stars
We know that this number is very high. There are probably billions of such planets in our galaxy alone.
Relevant number 27: The time between the Earth's formation and the appearance of life
A short enough number here might be a point in favor in claims that extraterrestrial life is common.
Relevant number 28: The time between the Earth's formation and the appearance of intelligent life
A short enough number here might be a point in favor in claims that extraterrestrial intelligence is common, although there is no such short number.
Relevant number 29: The total number of sky anomalies beyond any earthly or astronomical explanation
If this number is greater than zero, it may be a factor in favor of more optimistic estimates of the likelihood of extraterrestrial life.
Relevant number 30: The total number of reliable reports of abductions by extraterrestrials or sightings of extraterrestrials on our planet
If this number is greater than zero, it may be a factor in favor of more optimistic estimates of the likelihood of extraterrestrial life.
It is clear from this discussion that there are very many numbers that should be pondered by anyone trying to calculate the likelihood of life naturally appearing elsewhere and the likelihood of intelligent life naturally appearing elsewhere. How many did David Kipping take into account when calculating the likelihood of extraterrestrial life and extraterrestrial intelligence? He seems to have paid attention to only two of these numbers, number 27 and number 28. Kipping's cosmic analysis is therefore extremely lazy. Kipping's paper fails to even use the word "cell" or "protein" or "genome" or "DNA" or "complexity." He seems to have paid zero attention to the complexity of life.
We can call this kind of analysis a straw hole analysis, because the analyzer is like someone looking through a straw hole, seeing only one or two little things that might favor the conclusion he wants to reach, and failing to give proper consideration to many other relevant things. When someone does analysis so lazy, it is useful if he has some glittering distraction to make his slothful analysis seem more impressive. Kipping does this by using what I call math spraying.
We may define math spraying as the abundant use of arcane arithmetic to create some superficial impression of deep thought and intelligent analysis, particularly when such mystifying mathematics is not necessary, or when it obfuscates or distracts you from realizing the author is speculating or hand waving or engaging in dubious logic. The biggest math sprayers are theoretical cosmologists. They love to use math spraying to fill up their papers with so much arcane arithmetic that you might be impressed unless you realize that they're just speculating like crazy.
The arcane arithmetic in Kipping's paper is unnecessary because at the core of his reasoning is Bayes' theorem, which is a very simple mathematical equation. Here is the formula for Bayes' theorem:
P (A | B) = (P (B | A) * P (A) ) / P(B)
where A and B are different events, P (A | B) is the probability of A given B is true, P (B | A) is the probability of B given A is true, P (A) is the independent probability of A and P (B) is the independent probability of B.
Any paper using reasoning based on this simple formula should have had nice intelligible math that anyone could have followed. But Kipping somehow manages to fill his paper with a heap of indecipherable math gobbledygook that not 1 in 1000 readers will be able to follow. This is a very big example of math spraying.
Somehow, through some reasoning process that very few will be able to follow, Kipping ends up with the conclusion suggesting that life should have a high chance of naturally arising elsewhere in the universe. He states, 'Life would likely reemerge rapidly on Earth were the clock to be rerun." His gallons and gallons of math spraying might cover up the very simple fallacy at the center of his reasoning, which is a fallacy along the lines of reasoning that it must be easy for life to naturally appear, because it naturally appeared fairly quickly.
His reasoning seems to be based on the claim that we know that life naturally arose quickly. But we don't know any such thing. No one has ever observed abiogenesis (the natural origin of life from chemicals) occur, and we do not know whether it ever did occur. Life might have appeared on Earth only after some extraterrestrial spaceship planted it here, or only after some divine agent caused life to appear. The complexity of even the simplest life argues very strongly that it never could have appeared on Earth from natural processes. The person who argues "it must be easy for life to naturally appear, because it naturally appeared fairly quickly" is guilty of the fallacy of begging the question, of assuming the truth of a contested point, the truth of which you have no business assuming.
I may give an analogy to illustrate the kind of fallacy involved in reasoning such as "it must be easy for life to naturally appear, because it naturally appeared fairly quickly." Let's imagine someone living with six others in a house goes into his backyard and places a deck of cards on a patio table in the backyard. The person then goes shopping, and returns two hours later to find that the entire deck of cards had been arranged into a house of cards that rested on top of the patio table.
Suppose the person were to reason like this:
"Aha, I see that random wind gusts have formed a house of cards while I was gone. Since this happened relatively quickly, in only two hours, I conclude that it must be relatively easy for gusts of wind to form a full deck of cards into a house of cards. I conclude that if everyone in my town were to put a deck on cards on their backyard patio tables, and go away for a few hours, then very many of them would come back and find houses of cards that formed by wind gusts."
This reasoning is, of couse, utter nonsense. The speed with which the house of cards was formed is a minor factor here. Vastly more worthy of the person's attention is the gigantic improbability of wind gusts ever forming a house of cards. Instead of concluding that it is easy for wind gusts to form houses of cards, the person should have presumed that an unseen agent formed the house of cards that was too unlikely to have formed by chance. Similarly, when considering the chance of life or intelligent life randomly appearing by chance on a planet, we should focus on the gigantic improbability of such an accidental miracle of organization, which would be far less than the chance of the wind blowing 52 cards to all form into a house of cards.
Life and intelligent life may exist in great abundance throughout our galaxy, but such a thing is extremely improbable unless there is some agency causing vastly improbable arrangements of matter to happen. Calculations ignoring such an agency and giving proper consideration to all the factors listed above will calculate very poor odds of life and intelligent life appearing by chance elsewhere in our galaxy.
As for Bayes' theorem, it should be used only in cases when we know of the precise probability of each of the inputs of the theorem: the precise probability of Event A, the precise probability of Event B, and the precise probability of Event B given Event A. Whenever any of these three probabilities is not exactly known from observations, then you have no business using Bayes' theorem. People trying to use Bayes' theorem to calculate the probability of extraterrestrial life do not have any precise probability to plug in as two of the three required inputs of the theorem. Using Bayes theorem in such a case is mathematical malpractice, kind of like someone trying to calculate your life expectancy when he knows neither your age nor your health status.
Relevant number 15: The number of mammalian body plans specified in genomes
If we know that body plans are specified by genomes (DNA), then we might have some idea of how new large-sized organisms might appear (from modifications of DNA). This number is actually zero. DNA only specifies low-level chemical information, not high level structural information such as body plans. The nonexistence of body plans in DNA should make us lose confidence in any estimate of a likelihood of large organisms such as humans appearing elsewhere, since there is no real understanding of how such body plans could appear, contrary to boastful claims about this topic.
Relevant number 16: The number of organs, limbs or appendages specified in genomes
This number is zero. DNA only specifies low-level chemical information, not high level structural information such as how to construct an organ or limb. The nonexistence of such information in DNA should reduce our confidence in any estimate of a likelihood of large organisms such as humans appearing elsewhere, since there is no real understanding of how organs or appendages of such organisms could appear, contrary to smug brags about this topic.
Relevant number 17: The number of cell structures specified in genomes
This number is zero. DNA only specifies low-level chemical information, not high level structural information such as how to construct the incredibly complicated units that are cells. The nonexistence of such information in DNA should reduce our confidence in any estimate of a likelihood of large organisms such as humans appearing, since there is no real understanding of how the roughly 200 cell types required by such organisms could appear, contrary to pretentious boasts about this topic.
Relevant number 18: The number of natural protein molecules or natural genes that have been proven to have originated from random mutations, natural selection, or any combination of the two
Of the total number of different types of protein molecules in the animal kingdom (estimated to be between 10 billion and 10 trillion), how many have been proven to have originated from random mutations, natural selection, or any combination of the two? The answer is zero. This is certainly a relevant number to consider when we are judging the likelihood of large intelligent organisms appearing elsewhere through something like a Darwinian process.
Relevant number 19: The number of living things or functional proteins that have appeared through experiments realistically simulating the early Earth
This is a very important number to consider when judging the chance of life naturally arising elsewhere. If we knew that attempts to simulate the early Earth had producing a living self-reproducing cell, that would give us confidence that such a thing is not too hard. If we knew that attempts to simulate the early Earth had produced at least a functional protein molecule, this be a reason for thinking that maybe the natural origin of life was not too hard. But all such attempts have failed. Neither a living cell nor a functional protein has ever been produced in experiments realistically simulating the early Earth.
Relevant number 20: The number of biologically relevant amino acid types that have been produced through experiments realistically simulating the early Earth
There are twenty types of amino acids used by living things. The fewer the number of amino acid types that can be produced through experiments simulating early Earth conditions, the less likely it would be for there to occur the random appearance of life from such chemical units. The actual number of types of biologically relevant amino acids that have been produced in experiments realistically simulating the early Earth is no greater than one. Of the twenty amino acids used by living things, only glycine has been produced in experiments realistically simulating the early Earth. The famous Miller-Urey experiment that produced some amino acids was not a realistic simulation of the early Earth. Most other experiments producing amino acids do not qualify as realistic simulations of early Earth conditions.
Relevant number 21: The number of amino acid yields with homochirality that that have been produced through experiments realistically simulating the early Earth
In earthly life there is a propery called homochirality, which means that essentially all amino acids in proteins are "left-handed." The origin of this homochirality is a great mystery. No experiments designed to simulate the early Earth have produced any amino acid mixture having such homochirality. This failure is a reason for being pessimistic about the likelihood of the natural origin of life on other planets.
Relevant number 22: The number of nucleosides that have been produced through experiments realistically simulating the early earth
Nucleosides are molecular units that are building blocks of DNA. The fewer the number of nucleosides that can be produced through experiments simulating early Earth conditions, the less likely it would be for there to occur the random appearance of life from such chemical units. Nucleosides have never been produced in experiments realistically simulating the early Earth. You can read here about the failures of such experiments.
Relevant number 23: The total number of stars that have been searched for radio signals from extraterrestrial civilizations
This number is very relevant for any estimate of the likelihood of intelligent life appearing on other planets. If countless millions of stars have been searched unsuccessfully for radio signals, this would seem to reduce the chance that extraterrestrial intelligence is common.
Relevant number 24: The total number of neuroscience observations or case histories raising doubts about claims that intelligence comes from the brain
If there any neuroscience observations or case histories raising doubts that the brain is the source of the human mind or the storage place of human memories, this has a negative effect on any optimistic claims about the odds of intelligent life appearing on other planets; for if we don't understand where our own minds come from, we have no business calculating about the odds of intelligence on other planets. There are many such neuroscience observations and case histories which you can read about at great length at this site. They include observations of people with good minds or sometimes above-average intelligence who had lost most or almost all of their brains due to injury or disease, and observations that synapses consist of proteins with lifetimes far too short to store memories for even a year, let alone the 60 years or more than humans can remember things.
Relevant number 25: The total number of parapsychology observations or case histories raising doubts about claims that intelligence comes from the brain
If there any parapsychology observations or case histories raising doubts that the brain is the source of the human mind or the storage place of human memories, this has a negative effect on any optimistic claims about the odds of intelligent life appearing on other planets; for if we don't understand where our own minds come from, we have no business calculating about the odds of intelligence on other planets. There are many such parapsychology observations and case histories, including innumerable accounts of apparition sightings by reliable observers (with the same appartion often seen by multiple observers), along with countless accounts of people who had near-death experiences when their brains were shut down because of heart stoppage or cardiac arrest (including observations of details that should have been neurally impossible during such brain shutdowns).
Relevant number 26: The number of planets in the habitable zones of sun-like stars
We know that this number is very high. There are probably billions of such planets in our galaxy alone.
Relevant number 27: The time between the Earth's formation and the appearance of life
A short enough number here might be a point in favor in claims that extraterrestrial life is common.
Relevant number 28: The time between the Earth's formation and the appearance of intelligent life
A short enough number here might be a point in favor in claims that extraterrestrial intelligence is common, although there is no such short number.
Relevant number 29: The total number of sky anomalies beyond any earthly or astronomical explanation
If this number is greater than zero, it may be a factor in favor of more optimistic estimates of the likelihood of extraterrestrial life.
Relevant number 30: The total number of reliable reports of abductions by extraterrestrials or sightings of extraterrestrials on our planet
If this number is greater than zero, it may be a factor in favor of more optimistic estimates of the likelihood of extraterrestrial life.
We can call this kind of analysis a straw hole analysis, because the analyzer is like someone looking through a straw hole, seeing only one or two little things that might favor the conclusion he wants to reach, and failing to give proper consideration to many other relevant things. When someone does analysis so lazy, it is useful if he has some glittering distraction to make his slothful analysis seem more impressive. Kipping does this by using what I call math spraying.
We may define math spraying as the abundant use of arcane arithmetic to create some superficial impression of deep thought and intelligent analysis, particularly when such mystifying mathematics is not necessary, or when it obfuscates or distracts you from realizing the author is speculating or hand waving or engaging in dubious logic. The biggest math sprayers are theoretical cosmologists. They love to use math spraying to fill up their papers with so much arcane arithmetic that you might be impressed unless you realize that they're just speculating like crazy.
The arcane arithmetic in Kipping's paper is unnecessary because at the core of his reasoning is Bayes' theorem, which is a very simple mathematical equation. Here is the formula for Bayes' theorem:
P (A | B) = (P (B | A) * P (A) ) / P(B)
where A and B are different events, P (A | B) is the probability of A given B is true, P (B | A) is the probability of B given A is true, P (A) is the independent probability of A and P (B) is the independent probability of B.
Any paper using reasoning based on this simple formula should have had nice intelligible math that anyone could have followed. But Kipping somehow manages to fill his paper with a heap of indecipherable math gobbledygook that not 1 in 1000 readers will be able to follow. This is a very big example of math spraying.
Somehow, through some reasoning process that very few will be able to follow, Kipping ends up with the conclusion suggesting that life should have a high chance of naturally arising elsewhere in the universe. He states, 'Life would likely reemerge rapidly on Earth were the clock to be rerun." His gallons and gallons of math spraying might cover up the very simple fallacy at the center of his reasoning, which is a fallacy along the lines of reasoning that it must be easy for life to naturally appear, because it naturally appeared fairly quickly.
His reasoning seems to be based on the claim that we know that life naturally arose quickly. But we don't know any such thing. No one has ever observed abiogenesis (the natural origin of life from chemicals) occur, and we do not know whether it ever did occur. Life might have appeared on Earth only after some extraterrestrial spaceship planted it here, or only after some divine agent caused life to appear. The complexity of even the simplest life argues very strongly that it never could have appeared on Earth from natural processes. The person who argues "it must be easy for life to naturally appear, because it naturally appeared fairly quickly" is guilty of the fallacy of begging the question, of assuming the truth of a contested point, the truth of which you have no business assuming.
I may give an analogy to illustrate the kind of fallacy involved in reasoning such as "it must be easy for life to naturally appear, because it naturally appeared fairly quickly." Let's imagine someone living with six others in a house goes into his backyard and places a deck of cards on a patio table in the backyard. The person then goes shopping, and returns two hours later to find that the entire deck of cards had been arranged into a house of cards that rested on top of the patio table.
Suppose the person were to reason like this:
"Aha, I see that random wind gusts have formed a house of cards while I was gone. Since this happened relatively quickly, in only two hours, I conclude that it must be relatively easy for gusts of wind to form a full deck of cards into a house of cards. I conclude that if everyone in my town were to put a deck on cards on their backyard patio tables, and go away for a few hours, then very many of them would come back and find houses of cards that formed by wind gusts."
This reasoning is, of couse, utter nonsense. The speed with which the house of cards was formed is a minor factor here. Vastly more worthy of the person's attention is the gigantic improbability of wind gusts ever forming a house of cards. Instead of concluding that it is easy for wind gusts to form houses of cards, the person should have presumed that an unseen agent formed the house of cards that was too unlikely to have formed by chance. Similarly, when considering the chance of life or intelligent life randomly appearing by chance on a planet, we should focus on the gigantic improbability of such an accidental miracle of organization, which would be far less than the chance of the wind blowing 52 cards to all form into a house of cards.
Life and intelligent life may exist in great abundance throughout our galaxy, but such a thing is extremely improbable unless there is some agency causing vastly improbable arrangements of matter to happen. Calculations ignoring such an agency and giving proper consideration to all the factors listed above will calculate very poor odds of life and intelligent life appearing by chance elsewhere in our galaxy.
As for Bayes' theorem, it should be used only in cases when we know of the precise probability of each of the inputs of the theorem: the precise probability of Event A, the precise probability of Event B, and the precise probability of Event B given Event A. Whenever any of these three probabilities is not exactly known from observations, then you have no business using Bayes' theorem. People trying to use Bayes' theorem to calculate the probability of extraterrestrial life do not have any precise probability to plug in as two of the three required inputs of the theorem. Using Bayes theorem in such a case is mathematical malpractice, kind of like someone trying to calculate your life expectancy when he knows neither your age nor your health status.
The Probability of Life is Zero
ReplyDeletehttp://thegodparadigmdiscussion.blogspot.com/2020/05/the-probability-of-life-is-zero.html