Q: How do I estimate the probability that God exists?

Mathematician: Before jumping into this question, it is important to realize that probabilities are not objective, observer independent quantities. We can think of the claim that a particular outcome will happen with a probability of 0.30 as meaning (loosely speaking) that given the information available to me right now, if I could replay this scenario many times, then in about 30% of those occurrences I would expect that particular outcome would occur. Notice that this means that my estimated probability may change if the information that I have changes.

To illustrate this concept, consider what happens when different people have different information about the nature of a single coin. For instance, suppose that I flip a coin, and you have to guess whether the coin lands on heads or tails. From your perspective, you estimate that the probability of a head occurring is 50%, based on what you know about coins in general, and the fact that you have no knowledge indicating that a head would be either more or less likely to occur than a tail for this coin. I, on the other hand, am aware that this is a trick coin with a head on both sides. So from my perspective, the coin has a 100% chance of landing on heads. Little do I know, however, that the coin is in fact a magic coin (the warlock who sold it to me at the carnival forgot to mention this fact) — 30% of the time this two-headed coin is flipped it magically changes into a two-tailed coin before landing. Hence, from the warlock’s perspective, the probability that the coin will end up showing heads is 0.70, whereas from my perspective the probability is 1.0, and from your perspective it is 0.50.

So getting back to the God question, we cannot talk about a single, universal probability that God exists. Rather, this probability will necessarily be dependent on the information that you happen to have.

Another important observation is that it is problematic to throw around the word God relying on the assumption that we all know what that means. How are we going to define God? If it turns out that Zeus exists, would we consider that God? What if our universe was created by a pair of powerful, omniscient, omnibenevolent beings? Would we consider them both God? Or how about if our universe was created by an alien scientist, would we consider that scientist God?

We cannot possibly assign a probability to “God” without specifying further what is meant by this term. Hence, rather than a single God probability, it is more reasonable to consider the probability that each possible god G exists (using whatever definitions for G we care to analyze). This information can be encapsulated by a function P. For each event Gexists, representing the existence of god G, P(Gexists) gives the probability of that event (i.e. the probability that G exists). As we have seen, the function P will depend on all the information that you currently have, which we will call your evidence E. Therefore, it is more rigorous to write this function as P(Gexists|E). This is what’s known as a “conditional probability”, and the vertical bar “|” is typically read as “given”. Hence, P(Gexists|E) can be thought of as “the probability that god G exists given our evidence E.”

Estimating the function P(Gexists|E), which assigns probabilities to the existence of possible gods G, is no trivial matter. For one thing, the human brain misjudges probabilities all the time (See this, that, this other thing and also this for some standard examples). Despite these challenges, we can talk about some useful rules that should be taken into account during this process of estimating P(Gexists|E):

  1. If the evidence E that we have is really unlikely to have occurred given the existence of a particular god G (but not so improbable otherwise), then that will tend to make the god G less likely. An extreme example of this is that if G is defined to be “an all powerful god that would never allow human beings to live”, then because our evidence E includes living human beings, that god G can’t exist (so we’ve just disproved a god!). Another example is that if your evidence says that there is a lot of evil in the world, then that is going to make any very powerful god that wouldn’t allow evil pretty unlikely.
  2. The more conditions we tack onto our definition of a god G, the less likely it will necessarily be that the god G exists. For example, a god that “is omnipotent and omnipresent” is going to be strictly less likely than a god that is just defined to be “omnipotent” or just defined to be “omnipresent”, since the probability that two conditions are met is always less than or equal to the probability that just one of those conditions is met (and neither omnipotent nor omnipresent implies the other, making this inequality strict). Similarly, a god that “helped the Jews escape from Pharaoh” is going to be more probable than a god that “helped the Jews escape from Pharaoh by parting the sea”, since the latter is the same as the former except with extra conditions. And this is not a statement of opinion, but rather, a consequence of the rules of probability.
  3. Make sure that the way you use probabilities conforms to Bayes’ Rule. This mathematical rule tells us that something is evidence in favor of a particular hypothesis if that something is more likely if that hypothesis is true than if the hypothesis is false. So, for example, the fact that canaries exist is (a small amount of) evidence in favor of a creator god that loves canary-like-things (compared to the hypothesis of a creator god that doesn’t love canary-like-things) since the probability of canaries existing is greater if a creator god loves canary-like-things than if a creator god does not.
P(“God of two giant hands in the sky exists”) < P(“God of at least one giant hand in the sky exists”)


These rules aside, giving advice about how to estimate P(Gexists|E) is quite difficult. But, I can at least warn you away from a few very common but very flawed methods for estimating the probability of various gods.

Bad Method 1:

Set P(Gexists|E) = 1  for whichever god you were taught about as a child, and setP(Gexists|E) = 0 for all other gods. This strategy works well on average only if  (a) there really is a god and (b) that god is by far the most popular god. Given, however, that there is no religion which more than one third of the people in the world believe in (not to mention the huge amount of disagreement within each individual religion about the exact nature of god), this strategy will assign 100% probability to an actually existent god less than one third of the time, regardless of what the truth about god actually is. (At least, this is true as long as we consider the Muslim Allah to be a different god than the Christian one, and both of them to be different than Vishnu, etc.). In fact, the odds could be much worse, if it turned out that, say, only 3,000 people in the world have identified the one true religion (which implies that you almost certainly weren’t raised in that religion as a child, and hence that your function P(Gexists|E) will almost certainly assign 100% probability to the wrong god if you use this bad method).

Bad Method 2:

Use a definition of god that is vague enough that you yourself don’t have much of a clue what “god” really means (e.g. “god is a force” or “god is that which is good”), and then assign P(Gexists|E)=1 for this vague god and P(Gexists|E)=0 to, well, whatever is not covered by this definition. Definitions like these are just too fuzzy to mean very much. If you try to apply reasoning to fuzzy, ill-defined ideas, you’ll often get nonsense as a result. Case in point, lame attempts such as: “God is good” and “Good exists”, therefore “God exists.”

Bad Method 3:

Assign a high probability to things that appeal to you, and a low probability to things that do not appeal to you. Hopefully the problems with this approach are fairly obvious. You may have had a happy day dream about a guardian angel that is looking after you, you may desperately want there to be such an angel, you may spend hours thinking about such angels, but none of that constitutes useful evidence about whether an angel will actually catch you if you trip and fall down the stairs. You cannot (rationally) believe something simply because you want it to be true. You can only (self-delusionally) believe something because you want it to be true.

Bad Method 4:

Only seek out information that supports your pre-existing beliefs, and ignore or avoid information that might disconfirm your beliefs. In practice, this often amounts to starting with a high probability assigned to one particular god J that you happen to have been taught about, and starting with a low value assigned to P(Gexists|E) for other gods G. You then proceed to only ever read supportive literature (and talk to supportive people) arguing in favor of the god that you already think is likely, ignoring literature and people that discuss why god J might not exist. Of course, this approach naturally will cause you to keep increasing your probability P(Jexists|E) and keep decreasing P(Gexists|E) for the other gods, because you keep inundating yourself exclusively with information that supports what you already believed.

Imagine that someone alive in Greece in the 5th century BC were to follow this method. For instance, suppose that this person started out with only a moderately strong belief that Zeus exists, but then only ever listened to people talking about reasons why he should believe in Zeus. Because of this, his moderate belief in Zeus naturally would have risen over time until it became a strong belief. But this procedure would cause his belief in Zeus to rise whether or not Zeus exists! Hence, it is not a procedure that produces truth, it is merely a procedure that produces belief. This mistake is very common because people tend to surround themselves mostly with people who believe similar things to what they themselves believe, and members of religious communities work to convince each other to believe ever more strongly. For instance, our Greek friend would have been likely to spend most of his time around others that believed in Zeus, rather than those that were marking arguments against Zeus or in favor of a different set of gods.

In summary, to maximize your chance of believing the truth, you must not assume that what you were taught is necessarily true, you must define your terms as precisely as you can, you must surround yourself with the best possible arguments both for and against a particular belief, and you must evaluate these arguments objectively, without regard for what you want to be true.

You may at this stage be wondering: “How does the religious concept of faith factor into our probabilistic argument?” Well, the tricky part about faith is that, while it’s all very well and good to have faith in a benevolent god who does exist, it’s not a wise idea to have faith in a god who doesn’t exist. (I hope that most of us can agree on that point.) Therefore, one must choose carefully, considering the many mutually exclusive gods out there who are allegedly demanding our faith. Faith doesn’t really get us out of the probabilistic quandary of estimated P(Gexists|E). At best it just changes the probabilistic question from “which god should I believe in?” to “which god should I have faith in?” which doesn’t really help.

Probability theory provides a useful framework for thinking about God, not so much because of the specific nature of the God question, but because probability provides a useful framework that can be applied to nearly all questions of (non-tautological) truth.


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36 Responses to Q: How do I estimate the probability that God exists?

  1. dgsinclair says:

    Caveat: I’m not well versed in probability, so I’m doubting, not just out of coming from a theist position, but out of a lack of understanding of how it all works – so I could stand explanations.

    1. The more specific the definition of God, the less likely?

    I’m unclear on why this is necessarily so. I mean, I guess the probability that an ambiguous or broad statement is true is great, but how useful are such statements? I guess what I object to is the implication that the likelihood of God is small based on more succinct definition – less probable, perhaps, but improbable, not necessarily.

    Also, if two conditions are mutually inclusive (for example, necessary being and omnipotence), then including both in the definition would not change the probability – and for this reason, I might argue that all of the omni-great attributes might be as likely as only one.

    I know that might be a stretch, but just thinking out loud.

    2. Wm. Craig used a probablistic argument

    I found that Krauss failed to engage Craigs argument, but it sounds like he was arguing that the evidence is enough to get us behond a 50% probability. Do you think that any of the foibles you mention here apply to Craig’s arguments?

    3. Dembki on probability = 0

    In What Number Do We Use For Probability = 0?, I remarked on Dembski’s use of 10^-150 as statistical zero.

    This turns out to be what is called Dembski�s Universal Probability Bound. So much to learn.

    4. Pascal’s wager as risk calculation

    As part of a series, I wrote Pascal�s Wager – Part II: debunking the �all religions are equally improbable� ruse. In it, I applied the simple (likelihood x impact) equation we do in project management, and looked at Pascal’s wager – of course, if you have infinite impact, then even a small likelihood would mean that the risk of choosing atheism is infinite.

    Not that helpful, but if you back off the infinites, you get an interesting calculus, I think.

    5. Probability of Evolutionary Claims

    Even more interesting than applying probability to God is it’s application to evolutionary claims – such calculations have been done for a long time by both evolutionary proponents and critics.

    Of course, ID theorists use probability to promote their arguments and tear down Darwinism, perhaps convincingly.

    I think the best retort evolutionists can come up with is ‘there is a genetic process that we have not discovered yet which would reduce the improbability.’ I know that one experimental paper was recently published showing the incomprehensible improbabilty that two or three positive mutations to restore a bacterial process could occur.

    Also, see Quantifying the Statistical Challenge to Evolution

    Hope I’m not being too self promotional here, just wanting to contribute.

  2. David Iach says:

    Hi, I have a question. You said “The more conditions we tack onto our definition of a god G, the less likely it will necessarily be that the god G exists. For example, a god that “is omnipotent and omnipresent” is going to be strictly less likely than a god that is just “omnipotent” or just “omnipresent”, since the probability that two conditions are met is always less than or equal to the probability that just one of those conditions is met (and neither omnipotent nor omnipresent implies the other, making this inequality strict). ”

    I am not sure that is really the case. Lets say I am describing you a friend of mine and I say: my friend has a left arm and a right arm, he also has a right leg and a left leg. Would you say it is more probable that he only has a left arm but does not have a right arm and two legs? I guess not. Probably because if there is a friend of mine than its overwhelmingly more likely that he has all four of those. In fact if I tell you that all my friend has are two arms and two legs, he’s existence would be more improbable than if I tell you that my friend also has a head, two eyes, a nose and so forth.
    In the same way it might be that a god who is only omnipotent is actually less probable than one that is both omnipotent and omnipresent.

    It is less likely that someone likes both fishing and video games in the same time, than it is that someone likes only fishing or only video games because we know that there are a lot more people that like fishing but don’t like video games and people that like video games but don’t like fishing than there are people that like them both in the same time. But it is more probable that a person has both a left eye and a right eye in the same time than it is that he has only one of two eyes, because there are far more people with both eyes than there are people with only one eye.

    The problem when it comes to god is that we don’t know of any being that is either omnipotent or omnipresent or both so we can’t actually say it is like in the fishing/video games scenario or it is like in the two eyed/one eyed person scenario.

    Its 3:45 am, I might have said something stupid, but anyway this are my thoughts right now.

  3. The Mathematician The Mathematician says:

    Hi David, thanks for you comment. It helped me realize that the way I worded things was a little bit confusing. I made a slight change which should make it a bit clearer, modifying ‘just “omnipotent” or just “omnipresent”’ so that it reads ‘just defined to be “omnipotent” or just defined to be “omnipresent”’. The implication was not supposed to be that a god defined to be “omnipotent” was also specifically defined to NOT be “omnipresent”, but only that the condition of “omnipresence” is dropped from the definition so that there are now fewer conditions.

    So, in the arm example you give, the condition “my friend has a left arm and right arm” is less probable than “my friend has a left arm”, because saying “my friend has a left arm” has fewer conditions (it is in fact implied by “my friend has a left arm and right arm”) and is not intended to mean that the friend does not have a right arm.

    I hope that makes things clearer.

  4. g says:

    David, I’m pretty sure that our host means (1) It’s more probable that “an omniscient being exists” than that “an omniscient, omnipotent being exists” rather than (2) It’s more probable that “an omniscient but not omnipotent being exists” than that “an omniscient, omnipotent being exists”.

    You’re quite right that #2 could be wrong if omniscience and omnipotence tend to go together, as having a left arm and having a right arm do.

    dgsinclair: (1) “The more specific, the less likely” because, e.g., every (actual or possible) god who rescued the Jews from the Egyptians by killing the Egyptians’ firstborns is also an (actual or possible) god who rescued the Jews from the Egyptians; therefore, “There is a god who rescued the Jews from the Egyptians” cannot possibly be less likely than “There is a god who rescued the Jews from the Egyptians by killing the Egyptians’ firstborns”. (2) I think that if you want comments on Craig’s arguments you need to say more specifically which arguments and provide some pointers. (3) The term “universal probability bound” is Dembski’s and I don’t think the idea really contributes anything to human understanding; yes, in most contexts something that’s genuinely that improbable can probably be safely assumed not to have happened (but … deal out the hands for a game of bridge, note down the cards in each hand, do that again twice, and congratulations! you’ve just witnessed an event less probable than the “universal probability bound”); no, that doesn’t mean that a probability of 10^-150 is *the same as* a probability of 0; no, it doesn’t mean that evolution is wrong, and the examples creationists and ID advocates give to suggest it does are full of mistakes. (4) I don’t think I’ve ever heard anyone claim that all religions are equally (im)probable. (5) See #3: anti-evolutionists are very fond of statistical and probabilistic arguments, but time and time again they turn out to be full of errors.

  5. wrf3 says:

    … it’s not a wise idea to have faith in a god who doesn’t exist. (I hope that most of us can agree on that point.)

    Perhaps the wisdom of this should be debated a bit. After all, the number i doesn’t exist, except as a useful device for modeling part of the behavior of the external world. One cannot point to i apples or protons. i is a useful emergent property of the interaction of material.

    It isn’t hard, then, to make a case for something that is imaginary but is useful. We have evolved to think teleologically, and other studies have shown the utility of religion in increasing the quality of life.

    If materialism is true, then the only thing that really matters isn’t evidence (since the external world is the same for the theist and the atheist), but how brains process that evidence. And the only way to decide which brain is better is by those which have a reproductive advantage. Demographics don’t appear to favor the atheist. While atheism appears to be growing, it doesn’t appear to be keeping up with overall population grown. One writer has said, probably contentiously, “… [atheists] own children are converting to religion faster than religious children are converting out of it.”

  6. ATB says:

    I’m sort of surprised nobody has mentioned Swinburne’s Bayesian approach to the confirmation of religious hypotheses. The first third of his much discussed book “The Existence of God” deals with the relationship between philosophy of science and probability theory and theism (http://books.google.com/books?id=qL-GWmeSXCQC&printsec=frontcover&dq=the+existence+of+god&hl=en&ei=3XrFTd66HNLAtge2krSZBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDEQ6AEwAA#v=onepage&q&f=false), and in two subsequent books (“The Resurrection of God Incarnate,” “Revelation: From Metaphor to Analogy”) he actually assigns specific values to certain portions of the probability calculations and calculates the posterior probability of certain religious tenets (these are meant to be rough values, of course, intended to show the general force of his arguments). This isn’t some hack either — he’s an emeritus professor at Oxford, and he’s been enormously influential in philosophy of religion over the past several decade.

  7. g says:

    wrf3, of course it is not true that (conditional on materialism) the only way to decide which brain is better is by comparing reproductive success. Neither do I see any reason to think that (conditional on materialism) that’s the *best* way to decide. Atheism is growing faster than population in some places but not others; making long-term guesses about the population dynamics of religion seems like a mug’s game.

    ATB, Swinburne’s calculations are mostly OK (though arguably oversimplified) but the probability estimates he feeds into them are highly contentious; to my mind, some of them are absolutely ridiculous. (The same goes for some things that he claims are general principles of rationality; for instance, I think his “principle of credulity” as he states it goes way beyond what’s reasonable.) Being an emeritus professor is not necessarily incompatible with being a hack, any more than it’s incompatible with being absolutely crazy (which Swinburne probably isn’t, but some emeritus professors whom I shall not name certainly are). At any rate he isn’t *just* a hack, though.

  8. Chelly says:

    I think the use of ‘strictly’ is wrong as evidenced by the later sentence ‘less than or equal to’. A strict inequality is where there is no possiblity of the two sides of the inequality being equal. So just the ‘less than’ part and not ‘less than or equal too’. The probability of an omnipresent and omnipotent god may be equal to the probabilty of just an omnipresent god, but it cannot be greater than.

    @dgsinclair: including two mutually exclusive events in the conditioning will change the probability — it will make it zero, because two mutually exclusive events cannot both be true. I think you mean two independent events.

  9. The Mathematician The Mathematician says:

    Hi Chelly,
    Thanks for the comment, as I should have made this clearer in the post. It is true that a god defined to be “omnipotent and omnipresent” is going to be strictly less likely than a god that is just defined to be omnipotent or just defined to be omnipresent, so long as omnipotence does not imply omnipresence and omnipresence does not imply omnipotence. Here is why. By a basic rule of probability:

    Probability(omnipresence and omnipotence) = Probability(omnipresence given omnipotence) * Probability(omnipotence)

    Hence, if

    Probability(omnipresence and omnipotence) = Probability(omnipotence)

    that implies that

    Probability(omnipresence given omnipotence) * Probability(omnipotence) = Probability(omnipotence)

    and therefore (so long as Probability(omnipotence) is not zero) that

    Probability(omnipresence given omnipotence) = 1

    which means that if the inequality becomes an equality here then omnipotence implies omnipresence, or in other words, an omnipotent god has a 100% chance of also being omnipresent. I reject this implication (and the reverse implication as well), which is why I used the word “strictly”. The only other way the inequality could be an equality is if omnipotence or omnipresence had zero probability.

    But, sure, you can say less than or equal to if you like, that is still true of course.

  10. To find out about God, we go to the Bible. The Bible describes God and the nature of God. The Bible teaches that God is Truth. If God is Truth, then everything that can be proved is a part of God. Physics can be proved; Chemistry and math can also be proved. There are many more laws of nature that can be proved so it’s safe to say that the laws of nature are all a part of God. You don’t need math to prove God, just a little simple logic. If you want to dig a little bit deeper, then the laws of nature are eternal laws. We see the laws of physics working all the way back to the big bang and imbedded in the background radiation. Logic also tells us that the laws of nature had to come before the background radiation or the big bang because both are controlled by the laws of nature. In Proverbs 8:22-31 in the Hebrew text, you will find an outline of how God brought forth the universe. Solomon’s description fits with what we see with the Hubble telescope. How did Solomon know that?… By Understanding. … How did we get the laws of Physics? … By Understanding. … How did God separate Truth from fiction? … By understanding. … Understanding was the first thing that God brought forth in his creation of the universe. By total understanding God designed the elementary particles to bring forth all the chemical elements, the universe, and life. If you ever question if there is a God, then ask the questions,
    1. Where did the laws of nature come from?
    2. How did the elementary particles form?

  11. Brian says:


    Please replace the word God with Barney. Read your comment again with replaced words. Have fun with that. In short, a book can be written about anything, real or imaginary.

  12. Andrew says:

    A bit late but another comment for Herman is this statement: “To find out about God, we go to the Bible.”. (Not so) hidden assumption.

    How about the Koran? My not so sophisticated but much quicker reply (allowing my to go onto useful things) is, what is the probability that the text you read is inspired by “God” or people-say-weird-things-as-usual?

  13. Jordy B says:

    To all ‘truth seekers’..
    Perhaps you will find this link interesting:

    It’s a 4-part series. Watch it all, follow the instructions given, see what it does to you.
    I really respect this man for his sincerity and perseverance.

  14. If you want to use Barney in place of God you can, but you will have to explain to God (very soon) why you did that. If you want to read the Koran instead of the Bible you can, But someday real soon you will have to explain to God why you chose the Koran over the Bible. Keep in mind that God has a son named Jesus Christ and Allah don’t. There is a difference.

  15. Anthony Rose says:

    I’m really enjoying this site. Lots of fascinating info and discussion! In fact I’m spending too much time here right now, but I can’t resist this one.
    On the probability that G exists, I think that we can say with certainty that either it is 1, given the information we have, or it is entirely non-calculable.
    This is because we are using our minds to calculate the probability. Now, if our minds are pure matter and energy, then our thinking is entirely an effect of the atomic motion of our brain, and we have no superintendent means of changing the direction of our own atomic motion in any independent or self-chosen way. We will think what we will think, just as a stream follows its course. Whether we are actually being rational and logical or not, we cannot tell, no matter how much it may feel that we are being so, because we have no external power to re-direct our thoughts, no superior control over that part of nature which is us.
    However, if our minds have a super-natural element, then we do have a real ability to control and re-direct our thoughts, to interrupt or influence the tumble of atomic motion going on in there.
    If the first is true, then our probability that G exists is simply a predestined effect of atomic motion, rather than a truly fairly calculated equation.
    But if the second is true, then we have a non-phsyical, non-natural, supernatural element to our being: something of a higher dimension than the universe. This indicates firstly that there is a supernatural dimension with power of the natural, and seondly that there is existence in that dimension. Now of all the beings in that dimension, one at least is greater than the others. This one ought to satisfy the common definitions of G.

  16. Mark Wick says:

    I don’t think it’s useful to construct a probability model in the manner I’ve seen in this thread. However I do agree with one of the first points mentioned that the term “god” must be defined (otherwise you initiate a useless semantic battle). The definition of god as simply is and always has been is too ambiguous I believe because it leaves no room to include evidence other than evidence that refutes it (ie we know of nothing to ever have existed always and so the probability of such would approach zero from our understanding). The creator god, on the other hand, I believe enables us to consider various forms of evidence when considering the probability of a creator god. Now I believe some evidence can be factored into a universe-creating god but I see substantially more evidence to consider for a life-creating god. I see it as follows:

    The theory of abiogenesis describes how matter can turn into organic matter that replicates with increasing complexity. When mimicking Earth’s early atmosphere in laboratory conditions, simple matter readily forms nucleotides and polynucleotides (A,C,T, and G – the abbreviation for the “letters” of the genetic alphabet which comprise all living genomes). The theory also shows how a lipid layer can readily form a stable vesicle in the natural world that can actually consume another nearby lipid vesicle based on osmotic pressure (proto-competition). The initial lipid layers weren’t as well adapted as the lipid layers that exist today and monomers would have been permeable to the lipid membrane. While inside of the lipid layer, the monomers could for polymers that were no longer permeable and could no longer escape the membrane wall. Another quality common among living organisms are proteins. Again, in the laboratory, amino acids readily assemble when you mimic Earth’s early atmosphere. These amino acids can replicate into long-chain amino acids (proteins). Initially, these proteins would be simple proteins (no complex protein machinery) but time and fitness of a design to compete for resources would select for more and more complex and effective nucleotides, lipid barriers, monomer sequencing, enzyme production or accumulation, etc. allowing a natural process to explain systems of replication creating more and more complex “proto-cells” and eventually multicellular organisms. We are sure that the aforementioned can and readily would have occurred in early Earth’s aquatic conditions. However, it is difficult for many people to imagine even one of today’s complex eukaryotic cells evolving over time because we would have to witness precisely how this occurred over billions of years. People also have a difficult time imagining this process creating the complexity inherent in the human brain. Nevertheless, we can see that we are related to all life on Earth by examining our genome sequences. We all have paragraphs and paragraphs of identical DNA (nucleotide arrangement) as bacteria. Our genetic information is almost identical to chimpanzees (suggesting a closer genetic relation than that of bacteria). If we compare in this way to fossil records and theories of the chronological order of types of species, we see a triangulation that suggests a single origin (a single-celled organism). If you consider animal breeding, what you have is human selection rather than natural selection. This accounts for the evolution of wolf to chihuahua. In fact, when evolution is guided by human selection, new breeds of cats and dogs can come very quickly, even in one generation. Okay so at this point, we have all the evidence required to prove that species will in fact change over time (this comes from transcriptional errors [mutations] in genetic sequences). If we are genetically related to bacteria (common ancestry), we know that genetic transcriptional errors will in fact occurs in every generation (evolution/adaptation), and we are certain that the environment (competition, changing conditions and availability of resources, etc.) will select more and more efficient, complex, and well adapted life-forms over the course of billions of years, then to deny a common origin (a sort of singularity) would require quite the leap of faith. So far, when you weigh in all of the evidence here, you have a model that suggests only one thing: all life originated from a single cell, and although no one was around to observe it, the formation of that original cell can be readily explained through natural means (within the constraints of physics and time). Sure, no one was there to witness the process which took billions of years, but all evidence suggests it is what took place.

    On the other hand, you have religious literature which describes the origin of the Earth and life that contradicts what science proves about our world (the timeline for instance). These beliefs were perpetuated for thousands of years because we’ve always seen life come from life. A natural explanation made no sense. So the concepts of a creating-god (which would require an even more complex explanation to account for its creation) was posed and intimately tied to a religious ideology that has is now held by billions of people. Humans believe any given thing because of an emotional association that occurs simultaneously with the internal reflection of that belief. Our beliefs aren’t based on logic but rather how they make us feel. All of the thoughts behaviors in our brains have an associative emotional valance which prioritizes the realization of those thoughts and behaviors. For many people, the fear of eternal damnation is associated with not believing in god or rejecting him/her/it as a creator. There really isn’t any evidence to support the belief in a creator-god. Many people will refer to a religious experience they had yet that is thrown out the window when you remember that the brain specializes in simulating and supporting any belief you have. Religious experiences can be a product of the brain and there is no evidence to support otherwise.

    To tie all of this to probability, it would be difficult to factor in all of the evidence. This is why I believe a heuristic model to be of significant importance. Before one considers the evidence of a creator-god vs. abiogenesis and evolution it may seem logical to assign 50-50 probability. However, when you consider the evidence, the result is quite different. Evidence for a creator god: none that anyone is aware of. Evidence for abiogenesis and evolution as the creators for life as we know it today: supported by every bit of research and laboratory testing. Supported by fossil records. Supported by triangulation. Supported by genome sequencing. Supported by human-facilitated evolution (animal breeding). Supported by carbon dating. Supported by organic matter forming on its own in space. Based on the heuristic model that ties all of these things together. The list goes on and on. When the evidence here is tied to probability, it appears as though the only explanation that is supported whatsoever is a phenomenologically natural explanation. What percent probability is this? I don’t know because we certainly don’t have all of the variables but I’d guess it’s somewhere damn near 100%.

  17. Mark Wick says:

    ***Forgot to add that chemistry supports it and that the only thing that is lacking from all of these elements is precisely how abiogenesis was carried out because we don’t have any witnesses; nevertheless, the evidence to explain abiogenesis is abundant while creator-god evidence is inexistant (ancient written material isn’t evidence of a creator-god rather it is evidence of people writing things thousands of years ago).

  18. Rob says:

    God exists or does not exist but only in the minds of Man. God cannot be defined as rejecting a hypothesis and thus statistics is irrelevant to such a question. God requires a “leap of faith” within a supernatural world invented by Man thus defines no measurable criteria or likelihood thus not measurable or predicable. Those who want it true perceive it upon their faith in needing someone to Shepard them thru their life thus no complicated statistical based analysis is required. Just because you are a mathematician don’t think you have to force yourself to answer questions of a supernatural kind. Man is either ignorant thus looks for the supernatural to see what is on the other-side while those who believe in themselves look at supernatural as a fun house. Man has been around for only a few hundred thousand years so maybe that would;d have been quite a statistical challenge in itself. Can we get to exist 160 million years to meet the Dinosaur’s years of rule? What is the statistics on that?

  19. samir says:

    At that time Jesus prayed this prayer: “O Father, Lord of heaven and earth, thank you for hiding these things from those who think themselves wise and clever, and for revealing them to the childlike. Yes, Father, it pleased you to do it this way!” ~Matthew 11:25-26

    To have the Ultimate Truth revealed to you, you MUST have the following 3 prerequisites:
    1) Humbleness in your own knowledge and thus knowing there is a Mastermind Designer who is way greater than you, who have created you. God resists the proud but gives grace to the humble (James 4:6).
    2) Fear and acknowledgement of God as the Ultimate Power and Authority. The fear of the LORD is the beginning of ALL wisdom (Proverbs 9:10).
    3) Faith in Jesus Christ as Lord and Savior, even if you do not fully understand nor comprehend to start with.

    True understanding comes supernaturally from God. It isn’t deduced by study. No matter how much you read or study you cannot arrive at it. To get this grace, this undeserved gift, one MUST have faith in Christ. God saves whoever believes in His Son Jesus as Lord and Savior; salvation (and thus knowledge of Truth) happens at one’s appointed time.

    And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him. ~Hebrews 11:6

    God bless.

  20. Phyllis McLemore says:

    God is the net of frequencies we vibrate within. Who vibrates our DNA? Who vibrates our atoms and subatomic particles/wavicles? Who vibrates neutrinos and quarks and electrons? Who charges the charge of all of this? Might as well be a God because people don’t know how to do it.
    I used to read that God is love. God is omnipresence. I used to read that the Kingdom of God is within us. Why do people look out there when God is within us, vibrating as us? What is within us but vibrating atoms and quarks and electrons and the frequencies those come from? God is within us totally because we vibrate something that we don’t even know how to start. And it is healing always unless we stand in the way with our emotions.
    Read “Hands of Light” by the physicist Barbara Brennan. You can get a bachelor’s degree teaching all of the things above and more. She says that we vibrate totally 100% energy. This energy that we are vibrates so fast that it turns into light as it slows down at this dimension. Physicists cannot believe in faster than light activity because their instruments are not fine tuned enough to pick up frequencies faster than light. We come from a dimension that vibrates faster than the speed of light. All of our electrons vibrate faster than the speed of light. That is why spiritual people say that we are spirit. How can we be spirit and still live on earth? Is it a lie? If it is a lie, then Oprah Winfrey and a whole lot of other people have got it wrong. They say “we are spirit living human lives”.
    Physics is holding people back with what they believe to be true. I believe that beings that live in another dimension are my parents. When not one human would be my friend a voice in my head and from across the room, etc spoke to me with compassion. When I listened to this voice I made the right decisions. When I listened to people and their fears, I made the wrong choice. According to physics, energy beings that live in other dimensions are not true. Yet, I have learned more about the “real” nature of reality from reading books written by “spirits” such as Seth.
    And because of these books written by spirits I have experienced waves of energy flowing into me and out of me, sometimes to heal, sometimes to just feel.
    Because I have read these “spirit” books I have learned to heal myself almost instantaneously. Children should be taught this from the beginning.
    So when I have felt these waves of energy I like to think of them as faster than the speed of light electrons and quarks that magnetize to me because I want to help and teach healing. These electrons and quarks are full of all the compassion and intelligence that people are and more. Physics says our environment is full of electrons and quarks in a field of nonlocality. It is the 100th monkey effect.
    Prayer is for real and is stronger than a laser beam. It is electrons and quarks all swimming together to form healing, to remove restrictions in our bodies, to picture wholeness for us. Since we all vibrate 100% these electrons and quarks of compassion all the time, then we are constantly healing ourselves in the moment. It is our thoughts of non-unity with others that restrict this energy. Stop being greedy and sour and sarcastic and unforgiving and you will have healing because you are already a healing machine. We are already perfect. Picture perfection in a holographic universe and you will have it.

  21. slick rick says:

    proving that god exists is impossible because we can’t measure him. There’s a possibility that he does exist but who knows how huge that possibility is it could be infinitely small. A being who is omnipresent and omnipotent does bring up paradoxical problems. For example can god create a rock too heavy for him to lift? If yes he can’t lift the rock he can’t be omnipotent if no he can’t create the rock which also means he’s not omnipotent. Furthermore if god can exist out of time that means he doesn’t exist but being omnipotent means you can do anything right? From a religious point of view ( Christianity for example) how can evil arise from a perfectly good God ( the devil and sins for example). Personally i would say the probability that god exists is 0 but who knows

  22. Singing Rain says:

    How do I estimate the probability that God exists?

    Measure anything, any wave at all and you have a picture of God, a temporary spot, a standing wave, a snapshot, an estimate. Everything everywhere is vibrating as points within fields of eternal, indestructible waves people call God.
    God must be like a huge holographic multidimensional creature, full of so much energy that the sun is like a cell within IT’s body. Maybe our whole universe is like a cell within IT’s body. And we are exact replicas of this creature. Each of our atoms is vibrating this God energy of waves as points of God’s mind, as estimates.
    Our whole universe is magical according to what humans know how to do. Why do people take away this magicalness by calling it solid? When it is not. There is no solidity anywhere, yet God is measured in anything as everything, as estimates. Sounds like zen.

  23. Ben Hanowell says:

    Fascinating read. Here are my comments:

    1. Your approach is not necessarily more useful than asking a simpler question, which is, “Does any god or goddess exist?” Why? Because this is just a reformulation of your question, which is described by a categorical distribution over all the types of god situations (presumably including situations where more than one god exists and the special case where no god exists).

    2. Your arm example is incorrect and calls into question whether your “simple gods are more probably than more complex gods” axiom is correct. Why do I know your arm example is incorrect? Because empirically, having two arms is much more common than having only one, and this is common enough that it would swamp any prior distribution that placed low probability on having two arms. Similarly, there are many cases in genetics where heterozygotes are more common than homozygotes. The underlying reason is that the probability of having a left arm and the probability of having a right arm ARE NOT INDEPENDENT. As for the covariance matrix of all the properties of a god situation, it is….? What? It’s something that you have to estimate, that’s what.

    3. So we at trying to estimate the probability that particular god situations are true. We are not only uncertain as to whether or not a particular situation holds, but we are also uncertain in the probabiity parameters that define the categorical distribution over those situations. So if we are good Bayesians, we must take that uncertainty into account.

  24. Pingback: Evidence For God? | toadliquor

  25. slick rick says:

    interesting. Without any firm evidence there seems no way to distinguish Gods from each other or to even begin to state with certainty that a God exists. Therefore the way I see it when it comes to God existing you get 4 choices.

    1).An infinite amount of Gods exist for the infinite amount of Gods that can exist.
    2).Many Gods exist for the infinite amount of Gods that can exist.
    3).One God exists for the infinite amount of Gods that can exist.
    4).No Gods exist for the infinite amount of Gods that can exist.

    The question then becomes which outcome do you choose to determine the chances of God existing.
    If you choose option 1, well infinity/infinity is indeterminate. So option 1 doesn’t give you a clear outcome. Option 2 and 3 are basically the same in a sense. 1 or many are nevertheless integers and you could assign any definite integer a value no matter how big or small they are. Lets call that value x. x/infinity would be infinitely small if you approached it in terms of limits. lets say x was 1 perhaps and let say we had a situation like x/a.
    1/1000=0.001 and so on…
    the bigger a gets the closer x is gets to 0 but doesn’t touch it. If a was infinity x would be infinitely close to zero that you could say the chances of x were negligible and you could basically say it was the same as zero. In reality though x/infinity would also be indeterminate.
    As for option 4 well 0/infinity is 0. From all the indeterminate answers, it would seem that option 4 would be the most logical answer that no Gods exist, but realistically its possible for a God, many Gods to exist. So the question does pose quite the frenzy

  26. AC says:

    I strongly agree with The Mathematician that the more aspects of God we imagine & try to use in the calculation the less will be the probability of such God to exist.
    And that not all candidates for God have equal rating/probability. E. g., if natural God exists as subject to laws of Nature, the law of Time & law of Space, then such God must be subject to these laws. Being subject to laws of Nature/KnownTotalExistence such God has much higher chance to exist, then supernatural God who is not subject to any laws of our environment/Existence. Even higher change has the God who is the Reality/Existence/Totality/AbsoluteNature/Cosmos/AbsoluteWorld, since there is no need to prove that IT has a corporeal body, we can observe the existence of IT’s body all around us & partly within us. However, in this case we need to calculate the probability that God=Existence as candidate for God has its own special form of consciousness.
    Obviously, if we imagine a supernatural & unnatural God who is not subject to our known laws of Existence and doesn’t need to be part of our Existence or our Existence itself, then we enter entirely fictional/unnatural/vague/magical territory which is obviously allowing to anything to be/become possible and for such imagined or imaginary/fictional God to have any imaginable and unimaginable properties/aspects.
    Hence, the more real/natural, closer to Existence/Reality/Nature/Cosmos & all-encompassing a candidate for God is, the more likely IT can able to be in control of its inner content as its collective body. If Space is infinite and is the fundamental aspect of the God, then such eternal uncaused God=Existence has infinite body. I hope what was said will help some of you to assign some rating of realism to the possible candidates for God which you have on your list, before you begin to evaluate their probabilities.

  27. David Burroughs says:

    I know this is simplistic, but my roommate and I took a different approach and just looked at the values as “Man’s explanations for the Origin of the Universe”.

    We gave R (One version of a deity), a conservative 90 percent that your particular religion was based on your geographic location and time in history of birth. Looking at a few sources we also took a conservative number of deities since we have been able to record history and that number was 2780.

    We then looked at competing scientific theories for the origins of the universe and are still trying to make sure we have them all covered but that would include string theory,Cyclical Universe, Steady State theory, Plasma Cosmology theory, Universe always existed and Chaos theory.

    Now I am no cosmologist so I need to look at each one to make sure that one theory is not just an add-on to an existing theory, etc. And I am certain I am missing others, nut let’s take those figures. It would look like this.

    .90(G+T) 1
    R = ____________ or S = ____ = Probability of the Origin of Universe
    2870 6

    .90(3.13 X 10 -4) or .166 = Mans explanation of the Probability of the Origin of the Universe

    R = 1 version of God probability of the origin of the universe
    S = competing scientific theories on origin of universe

    I know this is simplistic, but I think it is a valid argument.

  28. David Burroughs says:

    Well the formula did not publish the way it should, but I am sure you can tell what I mean. I would love some input on it. I realize it is a different argument than “the probability of God”, but it is an argument I am trying to address.

  29. Lance says:

    It is easier to figure out the probability of spontaneous creation of life, than the probability of God. The lower the probability that life was not created by some being (like God), then the higher the probability that God exists.

  30. NXTangl says:

    If God is truly just, then He will take me in despite the fact that I did not believe in Him on the basis that there was no evidence for Him over thousands of other potential Gods, as long as I still spread His message of love and brotherhood. If He is not truly just, then I should not like to worship Him anyway, and any Eternal Bliss I might feel from getting to heaven would be brainwashing anyway. Finally, if He does not exist, then I’ll know I spent my life doing something that mattered: building an immortality machine.

    Paraphrased (except the very last bit) from something said by Marcus Aurelius.

  31. outsidethebox says:

    As far as I know the bible was not written by God and hasn’t spoken to anybody (although some people using certain mind-expanding substances may say otherwise).

  32. Tom Rose says:

    I am with Marcus Aurelius on this. Although I suspect that all the Gods mankind has believed in throughout history are inventions of his mind, and they are accepted voluntarily because they are in some way comforting and meet a psychological need, or involuntarily, as a result of childhood indoctrination, or through fear of the priestly class that used (and still uses) fear and religion as weapons of control.

  33. John S says:

    You aren’t thinking about all of the available evidence to study properly.

    1) Near Death Encounters with omnipresent beings.

    2) The lack of an explanation why people who do see these things believe that what they are feeling is real, and a common experience among NDERS.

    Now let me admit the math is still a struggle to get to, but setting a narrowly defined equation for the probability God exists, I have heard a figure that the odds that he doesn’t exist are 1 in a quintillion. Now that is tv for ya. I got on here, and expected a simple odds but you have expanded the idea to include a great deal of things I haven’t thought of, and some I have. OK, what I want to say is the above includes some knowledge of extraterrestrials, as well as the design, width and breadth of the universe. Taking constants and assuming the odds of things happening in a particular way for the exact outcome to occured naturally if possible would be the best way.
    Can I do it. Maybe if I get some serious probabilities time on a Neural Network, or a Fiber Optic networked Super Computer with Probabilities modeling software.
    So thanks for the mind meld.

  34. Gdavis says:

    The mathematical probability that the universe should be, rather than absolutely nothing has to be considered. My hypothesis is : it is easier for to have nothing exist eternally. Than something. Nothing is easier to maintain. There is no intelligent reason, given those two options why something ought to be, rather than nothing.

  35. RoundEarther says:

    John S

    People see a light at the end of the tunnel or something similar because they expect to, even atheists always have doubt and some don’t have a near death experience but their stories aren’t reported. Always be cautious when using anecdotal evidence in science.

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