This is a question that I’ve been trying to wrap my head around that can be best illustrated as an example. SETI is a project that tries to monitor radio signals to detect extraterrestrial intelligence. It tries to detect certain sequences of prime numbers for example.

If we did detect them, it may seem reasonable to postulate extraterrestrial intelligence. For otherwise, it would be a very lucky coincidence.

But I can think of other coincidences that do not make many people postulate designers. One popular example is fine tuning. As a refresher,

the universe’s fine-tuning for life: according to many physicists, the fact that the universe is able to support life depends delicately on various of its fundamental characteristics, notably on the form of the laws of nature, on the values of some constants of nature, and on aspects of the universe’s conditions in its very early stages. Various reactions to the universe’s fine-tuning for life have been proposed: that it is a lucky coincidence which we have to accept as a primitive given; that it will be avoided by future best theories of fundamental physics; that the universe was created by some divine designer who established life-friendly conditions; and that fine-tuning for life indicates the existence of multiple other universes with conditions very different from those in our own universe.

If, say, we take the route that there is no multiverse and this universe is all there is, then we have two theories we can compare: one that includes a supernatural designer and another that doesn’t.

Let’s compare the argument that fine tuning is a brute coincidence vs. the argument that the constants of the universe were fine tuned to create life by a designer. Suppose now that a theist argues this: “well, we don’t have examples of such spectacularly improbable meaningful coincidences happening for no reason. But we do have examples of spectacular meaningful coincidences at this sheer level of improbability being explained by humans (such as multiple lottery wins by the same person suggesting that the person cheated). This then gives us atleast a weak inductive reason to prefer the designer explanation than the non designer one.”

How sound would this reasoning be?

  • 2
    Related: Anthropic principle. Mar 9 at 21:46
  • 10
    The universe isn't fine tuned for life. An infinitesimal fraction of the universe we know of allows for life to exist, and even less for human life. We don't even know the mechanism by which physical constants could have been different, if any. We don't even know that they are constant. There is simply no observation that reasonably allows to conclude the universe is fine tuned outside from wishful thinking.
    – armand
    Mar 10 at 1:21
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    "well, we don’t have examples of such spectacularly improbable meaningful coincidences happening for no reason" This seems to be begging the question by requiring a reason which necessarily rules out coincidences. What would be the criteria to consider something caused without reason but by coincidence? Even the example of lottery winning is shaky - each individual win is already highly improbable but not designed. Mar 10 at 12:23
  • 2
    You ought to check out the questions posed by "thinkingman" (philosophy.stackexchange.com/users/62907/thinkingman) who has asked many variations of this type of question about reasoning. Mar 10 at 14:58
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    You seem to be forgetting the third option "the constants of the universe appear fine-tuned but there's a further underlying theory that we don't yet know which explains simply why they must be the values they are" - which if you ask me is actually the most likely Mar 11 at 16:44

10 Answers 10


Things can be plausible because we exist, but things can't be more or less probable because we exist than they otherwise would be, because the existence of humans to think that things are plausible is a necessary precondition for humans thinking things are plausible. We can't compare plausibility to humans between the "no humans" and "humans" states because in the "no humans" state there's no human to think that something is plausible.

  • By an increase in plausibility, I don’t mean the number of humans who think it is plausible. I mean how rational it is to believe it Mar 9 at 19:34
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    @Baby_philosopher How rational it is for whom to believe it, though? Dolphins? It can't be humans, as I said.
    – g s
    Mar 9 at 19:50
  • What is rational to believe isn’t dependent on humans existing. One can assume an abstract entity’s belief if that helps Mar 9 at 20:10
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    Perhaps any other thinking being would come up with the Fine Tuning argument? And it would be equally daft?
    – Scott Rowe
    Mar 9 at 22:17
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    It would be perfectly rational for a dolphin, if we assume that dolphins can rationally contemplate origins, for a dolphin to say to herself "Hehehe, stupid humans who don't just play and eat and screw all day instead design and manufacture complex interacting systems like boats! What dweebs! Wheee, a boat! Yay! Splish splash! That makes it more plausible that the ocean, a complex interacting system, might have been designed by older, more powerful dweebs. Yay, waves! Splash! Whee! Let's have sex and eat fish!"
    – g s
    Mar 9 at 22:23

The problem with the fine tuning argument is that it delivers absolutely nothing but a maybe. The suggestion is that the twenty or so key parameters in the standard model of physics where somehow 'tuned' for the purpose of generating life. Fair enough. So let ask some questions. Who did this tuning? How did they set-up the necessary values of the parameters as preconditions of the Big Bang? Given that the kind of carbon-based life we see on Earth need not be the only possible form of life, why did they tune the Universe the way they did? Why did they tune the Universe so that most of it is utterly uninhabitable to the kind of life that has emerged on Earth? Why would they tune it so that kind of life only emerges after billions of years? How did they know that setting the parameters in a particular way would lead to life emerging in a particular way so long afterwards? What motivated them to do it? If enabling human life was the objective, surely it was overkill to create a Universe so large that we can never inhabit more than the tiniest fraction of it. Why create a Universe that conforms to the standard model at all? Etc etc. A theory worthy of consideration would address at least some of those questions. Its things stand, you have absolutely no way of attaching a meaningful probability to the existence of a designer.

Remember also, that if you have an effect with two possible causes, the fact that one cause is unlikely does not in itself make the other likely.

  • This actually does kind of remind me of generating things in code: Let's say I want to find a specific word in a random sequence of letters (with a seed) - the larger I make the sequence the more likely it is that I find the word I'm searching; the rest is just clutter. It could be plausible to think that the unusable size of the universe is just necessary to give enough room for a positive match, like searching a pattern in randomly generated noise.
    – Katai
    Mar 11 at 9:55
  • That last sentence doesn't make a lot of sense to me. If there are two (and only two) causes, and one is unlikely (whatever that may mean) with a possibility of x, the other cause has a probability of 1.0 - x. If there are only two possible causes, then of them is 50%+ likely. A lot depends on how you define "likely" vs. "unlikely", but still...
    – Beska
    Mar 11 at 15:35
  • @Beska I know what you mean, but there is a subtle difference between that and what I mean. Suppose you win the lottery. It happened, but we would have said beforehand that it was highly unlikely that you would win at random, with a probability of one in five million, say. If the only alternative explanation was that you rigged the lottery, you would not say that the probability of that was 4,999,999 in 5 million. Mar 11 at 16:33
  • @Beska both of the reasons why you might win the lottery were unlikely, and their respective probabilities don't sum to one. Mar 11 at 16:36
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    @MarcoOcram The respective probabilities of them being true do equal to one. But in this case, you were referring to the probability of a person winning the lottery given chance (I.e. not rigged). That is not the same as the probability that the lottery win occurred by chance. That would be a value p and 1 - p would be the probability that it is rigged. I’m not sure how you can define a probability for causes though. It seems inscrutable and possibly meaningless Mar 12 at 0:41

How sound would this reasoning be?

Not particularly, since it hinges on an assertion that is only upheld by blatantly ignoring the scope of its own example.

It primarily boils down to what one considers a "spectacularly improbable meaningful coincidences happening for no reason". This hides an internal conflict in the definition - if we know the reason why a coincidence happened, can we even consider it spectacularly improbable?
Notably, this is likely to be weighed differently by people agreeing or disagreeing with the reasoning. If a valid reason has the predictive power of a "theistic designer", then assigning such a reason does not increase our predicted probability of an event - we cannot predict the designer without reducing them to some automaton. If instead a valid reason must have the predictive power of, say, the scientific method then a reason (including "no reason"!) necessarily increases our understanding of the underlying mechanism and thus increases the probability, since we can predict the occurrence better. Thus, this categorisation implicitly selects against events which people that disagree would confidently acknowledge to have "no reason".
This bias already makes the reasoning not particularly sound.

However, in its counter example it hides - possibly behind the conveniently movable goalposts of being "spectacularly improbable meaningful coincidences" - an event which is exactly an example for a coincidence without reason: A specific person winning the lottery at all! Sure, the lottery itself and the persons winning numbers may be designed (they don’t actually have to be!) but the outcome notably is not. The coincidence of drawn and selected numbers matching is highly unlikely, yet not caused by design - which the reasoning even acknowledges by considering a forced (i.e. designed) winning event as not a proper lottery game but cheating instead.

  • This is a bit difficult to parse through. Do you mind expanding on this? Suppose that there is a theory that says a certain seemingly improbable and meaningful coincidence (outside the capacity of human design) occurred without further reason and a theory that says it occurred by a supernatural designer. Now, does the existence of humans designing things that would otherwise be very improbable meaningful coincidences give any sort of (even weak) support to prefer the supernatural theory over the other (such as in the case of fine tuning)? Mar 10 at 23:38
  • @Baby_philosopher I don’t see why the existence of humans, and the fact that some of them design some things sometimes, should have any support to things outside the capacity of human design and especially not extremely outside of it. Just because there exist people that are 6 feet tall doesn’t make it any more likely that there are people who are 12 feet tall let alone 24 feet. Mar 11 at 6:20

We know without need to question, that there are other "types of designers".

Beavers build damns, and somewhat complicated homes with underwater entrances for security. Their creations are not random accidents... they envision, gather resources, build, and settle in. Amazingly efficiently.

Weaver birds build complicated nests that often hang by their own strength from telephone poles or treetops. Just one of many birds to build complicated nests.

Bees create honeycombs and then fill them with honey. lol... I realized I was demonstrating creation by the birds and the bees. But they do.

Nature is pretty amazing.


Both multiverse/anthropic and design hypotheses are reasonable inferences from Apparent Fine Tuning.

A wildly improbable coincidence is logically possible inference, but comes with no intrinsic reason to accept it, unlike the other two (multiverse is an inference off the stochastic nature of QM, extended to universe creation, design hypothesis is inference off human and animal design agency). As a fundamentally unexplainable improbability, it also breaks the principle of methodological naturalism, of seeking for an explanation for things.

Both a multiverse, and a designer hypothesis, come with testable consequences.

For a multiverse, the most noteworthy testable prediction, is that when a universe supports life, most of them would be NON OPTIMIZED for life, hence one would expect a multiverse hypothesis to be fine tuned, but pretty far off optimum. and this is actually the case for our universe. Life is only possible in a tiny fraction of the mass/energy of our universe, and was not possible for several billion years after the universe started.

Most other aspects of a multiverse hypothesis are not testable, at least in its current String Theory form, because String theory has infinite free variables. See: https://www.amazon.com/gp/customer-reviews/R3JVQDAK1408BR?ref=pf_ov_at_pdctrvw_srp vs. https://www.amazon.com/gp/customer-reviews/R6JY5GBLAV2BV?ref=pf_ov_at_pdctrvw_srp

Design hypotheses are also partially testable. The most noteworthy tests are for the design claims of the world's religions, and these all suffer from refutations. Design is to achieve purposes, and one would expect deities to do better at achieving purposes than humans do. Our universe, if designed by a competent deity, should reasonably be expected to reflect and reveal the design purposes and character of the deity. Our universe, while fine tuned for life, is not well designed for it. It is also not well designed for any of the multiple other potential objectives proposed for deities: diversity of conditions (after the 10,000th galaxy, and 10 billionth star system, why not try something different?), beauty (some aspects of this universe are astonishingly beautiful, but far more are -- not), moral virtue (life multiples to the point of starvation, everywhere, AND must destroy other life to thrive), etc.

IF our universe is designed, then the designer can reasonably be inferred to not be very skilled at achieving goals, which is surprising given the level of skill needed to design a universe. An only partially successful school project, or a design by dysfunctional committee, make more sense as a design agent than a single masterful intelligence.

Both design and multiverse need to be further fleshed out, to see how well they can be evaluated with more testing. Design is, to my judgment at least, the more testable of the two. One has to have agents, operating with power over this universe, from some other plane. Of our current otologic options, this is closest to spiritual dualism, and can be tested by testing for spiritual dualism. The parapsychology project, ghost investigations, search for minor spiritual entities (sprites, demons, etc.) are all experimental directions that can be pursued.

In contrast, multiverses seem to be intrinsically non-interacting, and hence are very difficult to test for.

  • Isn’t everything a wildly improbable coincidence? The specific sequence of coin tosses if I toss the coin 100,000 times is wildly improbable. Would you say that there is no intrinsic reason to accept that that was a coincidence? Mar 10 at 1:10
  • @Baby_philosopher -- Meaningful outcomes that are wildly improbable, under naturalism, require an explanation if 10^n of random outcomes would not be meaningful. Intentional agency, or a selection process such as natural selection with massive variability, or the anthropic principle with a multiverse, can both explain meaningful outcomes. Naturalism calls for an explanation.
    – Dcleve
    Mar 10 at 2:13
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    So if I think about my ex girlfriend and she calls me right after that instant, it requires an explanation? @Dcleve Mar 10 at 3:00
  • @Baby_philosopher I don't know. Do you think about her a lot.? Does she call you a lot? Was the call important in any way?
    – Dcleve
    Mar 10 at 4:55
  • Let’s say I don’t think about her a lot and she doesn’t call me a lot and the call was very important @Dcleve Mar 10 at 5:38

If anything, I think it's the opposite -- human “design” is decidedly not intelligent. We come bare-bone hardware, with no knowledge of the world around us preinstalled (the concept also known as tabula rasa). Neither we have a data-port or any other means to download our "software". The only way for an individual to acquire their copy is to piece it together, model by model, in their mind. Not only it takes considerable amount of effort, one needs to be quite lucky to receive the right puzzle pieces when the moment is right. And even in the best circumstances, the hardest part is to start -- to connect your first dots, to have your first "a-ha" moments.

That's why many give up -- and that's why this world remains a mess. Many philosophers, poets, and scientists who managed to complete their copies of the puzzle realized, at some point, that all evil and suffering in this world boils down to sheer ignorance -- the ignorance of our own nature, first and foremost. And the reason that ignorance persists is not because we lack the knowledge as humanity but, again, because it is so difficult to translate even the most readily available information into individual understanding.

This, therefore, has been and still remains the holy grail of humanity -- to overcome our "design flaw". To find a way to teach every child (or adult) the mental skills that would let them put together and rely on their own understanding, their own knowledge, their own truth. To teach everyone to think critically, to think themselves.

  • Yes, we've done a better job in 200 years designing machines that can learn and connect with each other than evolution did in 200,000
    – Scott Rowe
    Mar 10 at 22:10
  • 1
    @ScottRowe -- and I hope we'll learn from that experience to better understand our own nature. Mar 11 at 4:17

Bayesians might look at the Bayes factor, which measures how much an observation of evidence changes the ratio of out prior beliefs. The Bayes factor is the ratio of the likleihood of the observation, given the two hypotheses.

So H1 = "designers exist"; H2 = "designers don't exist", O = "observation that humans exist"

K = P(O|H1)/P(O|H2)

if K > 1 then that means the observations should increase our belief that designers exist.

K > 1 if P(O|H1) > P(O|H2)

so the question is, is it rational to think that it is more likely that humans exist given that designers exist than if they don't.

If you believe that it is a coincidence (H2) then it is very unlikely that we exist and P(O|H2) is very small. If you believe there is a designer, then it depends on what you believe about the designer. If you believe the designer likes designing observers (e.g. us) then P(O|H1) = 1. Under those circumstances, yes, the existence of humans increases out rational belief about the existence of a designer. This doesn't depend on your prior belief about whether designers exist or not, P(H1) = 1 - P(H2).

However, it may not change our belief very much. If you believe that P(h1) = 0, then no evidence will overcome your profound disbelief.

At the end of the day, most discussions about this are unlikely to make much progress from your priors, especially as most people are not able to formally state their beliefs about e.g. what the designer is likely to do, should they exist.

BTW the answer to the question in the title is self-evidently "yes". Does the existence of leopards increase the plausibility of other big cats? Why should this be a special case of the existence of a member of a putative group not increase the plausibility of the existence of other members of the group?

  • Perhaps because other kinds of designers would be supernatural and we have no direct evidence of them? It seems that similarities should only be considered when relevant. Otherwise, the existence of white balls would increase the plausibility of white goblins since they’re similar in colour, but that doesn’t seem to intuitively hold weight Mar 10 at 15:45
  • @Baby_philosopher if you want to use reason you need to state your assumptions. P(O|H2) is negligible, to have P(O|H2) > P(O|H1) you would need to have a designer that really didn't want to create us - is that what you are saying? Your goblin example is specious as you are picking an unlikely member of the group of white things, rather than considering whether it makes it more likely that the group of white things has other members - which would be a consistent analogy. i.e. you are introducing a second unlikely element and it is the second element that makes it more unlikely. Mar 10 at 15:54
  • Bayes factors help us to reason about sorts of designer. If the designer is of the sort that tries very hard not to create humans, then our existence is reason to believe a designer doesn't exist. If the designer is the sort that likes to create things like humans, then our existence increases our rational belief in that sort of creator. Mar 10 at 16:00
  • “P(O|H2) is negligible” Not quite. In a deterministic universe with no designer that leads to humans, P(O|H2) is 1. You might argue that the kind of world that is determined to result in humans without a designer has a low prior probability, but one can argue that any kind of supernatural designer also has a low prior probability. Although personally, I don’t like the talk of probabilities when it comes to speculative hypotheses. You can simply discuss reasons for and against and the numbers are rarely relevant @Dikran Marsupial Mar 10 at 16:14
  • @Baby_philosopher "Not quite. In a deterministic universe with no designer, P(O|H2) is 1" no, you are confusing the fact that humans have been observed with the probability of observing a human if there is no designer. One is an unconditional probability, the other is a conditional probability. " supernatural designer also has a low prior probability" as I said in my answer, the Bayes factor is independent of the prior probability. "I don’t like the talk of probabilities when it comes to speculative hypotheses." you are sounding more and more like Thinkingman. Mar 10 at 16:19

No, the existence of humans does not increase the plausibility of a "designer" (i.e. God), unless of course you already believe in God.

The concept you are looking for is the anthropic principle. There are many variants of said principle, classified in "weak" and "strong" forms.

Strong antrophic principles boil down to intent (of some kind of designer): some aspect of the observable universe was designed in the way it is to allow humans (or intelligent live in general) to develop.

Weak anthrophic principles, instead, boil everything down to "survivorship bias". The features of the universe are what they are for whatever reason (not necessarily involving a designer or intent); and for whatever reason they allowed intelligent life, or an observer, to develop. Hence we observe. We cannot observe an universe which does not allow intelligent life because we would not exist.

Take from that what you will. If you already believe in god, it is easy for you to also believe in a strong anthropic principle. If you do not believe in god, then the weak antrophic principle explains everything just fine and the strong variant seems far-fetched or a prime candidate to be snipped away by Occam's Razor.

A slight tangent:

Note that the weak principle tells you absolutely nothing. It does not tell you that there are gods, nor intent, nor designers, nor multiverses, nor anything else whatsoever. If this seems "improbable", then that is our problem not the problem of the universe. This is the same as evolution in general: we just cannot imagine the time spans, numbers and probabilities involved. For a long time, opponents of evolution have brought the example of the eye, which presumably is too complex to have developed by random processes. Today, we are much farther - there are very plausible explanations (and the eye alone is just a tiny, tiny aspect of modern mamals, by far not the most complex issue).

Unfortunately, nothing of this kind of research is very available to the general public (if this interests you, I encourage you to read The Selfish Gene in its most current edition). For some people, our modern understanding of genetics helps a lot to accept that maybe, just maybe, the "finetuning" of the universe isn't required to be all that fine, anyways, as the very general principles of what we know about evolution today (without going into any specifics observed on earth) would probably work everywhere...


Does the existence of humans increase the plausibility of other kinds of designers?

Certainly, but plausibility is no guarantee of possibility or probability. These terms are not interchangeable.

Faster than light travel

This may be plausible (believable) but that doesn't mean it's possible or likely. Based on current knowledge, it's impossible but the inability to predict future discoveries keeps it plausible. Probability is not-applicable in this example.


There is an obvious answer to this question. But it seems to be elusive for the majority of people, probably because of the way the human brain was designed and programmed.

There are two main perspectives to think about ourselves and our understanding of the world.

  1. The ant is sitting on the leaf and looking at the world.

  2. The view from the perspective of a creator's level.

Yet, we fail to try to have a look from the creator's point of view.

If you try to look from above, you will quickly establish some of the important points of our existence:

  1. Is this world the original copy or just one of the numerous digital copies?

  2. What is the purpose of this particular copy (every computer simulator has some purpose)?

  3. What are the main rules that maintain the balance, human energy and desire to achieve meaningful results of this simulation?

  4. The most important truth - when (and if) we will be able to create our own world simulator and become creators themselves.

  • Okay, I'll bite. I read your post and still don't see an "obvious answer". Is it 42?
    – mattdm
    Mar 11 at 14:28
  • @mattdm - Sorry, I thought it was obvious. You need to get outside your box, and get into the head of the creator instead. Mar 11 at 23:01
  • I can do that as a thought experiment, just as I can do the experiment of considering the perspective of an ant on a leaf (and the related analogy). But, given that I have a limited mind, and one that is surely infinitesimally small compared to what some creator-mind must be, it seems like quite a lot of arrogance or even hubris to imagine that any such efforts would yield anything close to truth.
    – mattdm
    Mar 12 at 14:13
  • The four points you suggest seem really, really unlikely and seem to skip a lot of steps. (Digital copies? Why computer simulator? Where did human energy come into it? Wait, we've already decided that it's a simulation? Our goal is to become simulators....? To me, this reads more like putting whatever theoretical creator you're describing into an ant-sized box than the other way around.
    – mattdm
    Mar 12 at 14:15
  • @mattdm - Most people on Earth would agree with you. But I think your objections are more emotional than logical. For example: "But, given that I have a limited mind, and one that is surely infinitesimally small compared to what some creator-mind must be" - Aristotle lived 2400 years ago, computer processing capacity to start building "The Matrix" is expected 300–400 years from now. Do you think human intellectual capacity will make a giant leap in the next 400 years compared to Aristotle's time? Mar 12 at 22:51

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