The Anthropic Principle:

is Fine Tuning of Nature due to

Multiverse and/or Intelligent Design?

 Three explanations for a fine-tuned world that is "just right" for life: 
Is this fine tuning due to INTELLIGENT DESIGN and/or a MULTIVERSE?

by Craig Rusbult, Ph.D.

Why is an explanation needed?

      Fine Tuning of Nature in Our World

      Sunshine warms our bodies and grows our food.  But why do we have sunshine?  It occurs because natural processes — which depend on the mass of particles, conversion of mass to energy (e = mcc), rate of nuclear reactions, and sizes of nuclear and gravitational forces — are "just right" to produce a balance between opposing forces.  One force pulls the sun's fiery atmosphere inward, while others push it outward, in a cosmic tug-of-war lasting billions of years.
      To understand fine tuning, imagine that you are sitting in front of a control panel with dozens of dials.  To allow life, each dial — which controls one property of nature in the universe — must be fine-tuned to a specific setting within a very narrow range.  You are alive, reading this web-page, because all dials are properly tuned, so we have stable atoms and molecules, stars that produce energy and heavy atoms (our bodies are made from stardust!), the amazing chemistry of DNA, water, and enzymes, and much more.
      An amazing discovery of scientists, in recent decades, is that many properties of the universe are "just right" for life.  Most scientists are convinced that the fine-tuning constraints on a universe that allows life or produces life are very tight because small changes would make the existence of life impossible, and that the probability of a universe having these properties (fine tuned to be "just right for life") is extremely low.


TWO THEORIES claim to explain why our universe is what it is:

      • One Universe (with Intelligent Design)

      One response to the fine tuning is "wow!"  And the simplest causal theory is divine intelligent design plus design-directed action, with our universe being designed and created.  We can imagine a process-of-designing in which God ran complex thought experiments with many different combinations of dial settings to "see what happens" for each, at all levels of natural phenomena ranging from the physics of galaxies to the chemistry of life, before selecting the optimal combination of nature-properties to use in creating our universe.   { This theory proposes one of the four types of intelligent design. }

      • A Multiverse (with many universes, and maybe Intelligent Design)

      Scientists have analyzed the probability of a universe capable of supporting life-forms that are intelligent, and have estimated the odds to be extremely low.  If there is only one universe, and it was not designed for life, we must conclude that we are extremely lucky.  But if we live in a multiverse containing an immense number of universes, then (if the universes are numerous enough, and if their properties are distributed across a wide enough range so it's a diverse multiverse) the odds would favor having at least one universe with intelligent life.  Basically, a diverse multiverse provides a way to beat the odds and thus decrease the logical support for design-claims.


Intelligent Design is compatible with
the Anthropic Principle, a Multiverse, or a Grand Unified Theory

      The Anthropic Principle (with or without Intelligent Design of Observers)

      Perhaps we should just say "so what?" because if we are observing a universe, it obviously must have properties that allow our existence.  This anthropic principle — which states that because humans exist, we MUST observe a universe consistent with our existence (due to the anthropic selection effect for the type of universe-properties we can observe) — is logically valid, and is compatible with either design or non-design so it doesn't favor either possibility.  This neutrality, with no logical support for intelligent design or against it, occurs because the anthropic principle does not explain WHY our universe is fine-tuned for life.  But the anthropic principle might imply two selection effects:  in addition to restricting WHAT we can observe in our universe, in a multiverse it might explain WHERE fine tuning is observed.  And beating the odds might explain WHY we see fine tuning.    definition of anthropic principle — in four versions ! }

      Would a multiverse require intelligent design?

      Robin Collins explains why "even if a ‘many-universes generator’ exists it seems to need to be well designed" in order to produce a multitude of universes with widely varying properties.  If this is true, the two most plausible theories are:  • one universe that was intelligently designed, or   • a multiverse (with many universes) that was intelligently designed.   But if you think a multiverse does not need to be designed, an undesigned multiverse is a plausible theory.
      Therefore, the choice is not
      EITHER design OR multiverse,
      but instead is
      EITHER designed universe or designed multiverse OR non-designed multiverse,
      so currently we have THREE plausible theories, not just two, for explaining the fine-tuned "just right" world we observe:
four combinations
(and we live in it)
is plausible and is
   one option for theists 
is extremely improbable
( practicaly impossible? )

   (with many universes)   
is plausible and is
one option for theists
is plausible and is the
only option for non-theists


two options:  1) You can read a condensed summary of the main ideas in this page — Was our "just right" universe designed by God? — to get a quick "big picture" overview, and then return to this page for more ideas in more detail.   2) Or just continue reading below.


      Life-Allowing Universe and Life-Producing Universe:  We are here, and this logically requires (as stated in the anthropic principle) that the properties of nature must allow intelligent life;  nature must be able to maintain life, letting us survive.  A more demanding requirement is a universe with properties of nature that also can produce intelligent life by 100%-natural evolution.  A universe that is only life-allowing (but not life-producing) is logically consistent with a basic anthropic principle, unless it is supplemented by assuming a totally-naturalistic history of nature, with this assumption based on methodological naturalism (requiring "only natural process in scientific theories") and/or philosophical materialism (claiming "only matter/energy exists").   /   Some theists, who propose miracles during the initial origin and/or subsequent development of life, think a life-allowing universe is sufficient.  But this is not sufficient, so a life-producing universe is necessary, for anyone proposing a totally natural history of life, for theists who are evolutionary creationists, plus deists, pantheists, rigid agnostics, non-theists, and others who claim a naturalistic history.
      Universe-Types and Universe-Actualizations:  If a multiverse exists, we need to consider both factors (types & actualizations) when we ask "how many universes are in the multiverse?"  Using calculations based on string theory, scientists estimate that a multiverse might contain 10500 different universe-types, each having different laws of nature;*  and each type might occur in an immense number of actualized-universes of the same type — so they would all have the same properties of nature — but each actualized universe would have different initial conditions (plus the divergences described by chaos theory) and thus each actualization would have a different historical result for "what happens" during the history of that particular universe, even if they have the same properties of nature.  In addition, each actualized universe might be (according to a purely speculative interpretation of quantum physics popularized by Hugh Everett) "quantum-split into many worlds" that are divergent variations on the same basic history.   {* When claims for possible universe-types are based on string theory, most estimates range from 10100 to 101000, with 10500 often cited as a middle-of-the-range number.}
      Informed Speculations:  I say “might contain... types of universes” and “might occur... actualized universes” to remind you that these should be considered potential types and potential actualizations because, as explained below, “there is no direct observational evidence for a multiverse.”

      Mechanisms - How could a multiverse be produced?  In an effort to explain the origin of a multiverse containing many universes, including our own, scientists have proposed a variety of mechanisms:
      According to one currently popular proposal:  An immense number of universes (including many actualizations for each of the many possible universe-types) are produced, like bubbles in foam, during a period of extremely rapid chaotic inflation in the early stage of a Big Bang;  after this process begins, it continues producing additional "big bangs" forever, so it is future-eternal and is therefore also called eternal inflation, chaotic eternal inflation, eternal chaotic inflation, or chaotic inflation.  The many variations of nature-properties (in different universe-types) are produced by many variations of string-properties that form the string landscape predicted by M-theory, which elegantly unifies five versions of string theorydifferent sets of string-properties specify the nature-properties in different types of universes, and let universes have diversity, analogous to the way that different combinations of DNA specify the biological-properties of different organisms, and let organisms have diversity.   {the DNA analogy is from Leonard Susskind}
      Proposed mechanisms for producing universes have included the chaotic inflation model (above), an ekpyrotic model with a cyclic sequence of colliding string-membranes, other models (now generally considered implausible) in which our universe has passed through sequential cycles, collapsing black holes, a purely speculative philosophical interpretation of quantum physics claiming that each universe is quantum-split into "many worlds" at every instant of time, and more.

      Max Tegmark imagines and describes four possible multiverse-levels:
      Level 1 — our universe is part of a vast mega-universe (produced by inflation) containing many large spatial domains, including the one where we live, that are actualized-universes;  these are all the same universe-type, but with differing initial conditions.
      Level 2 — contains many Level 1 multiverses, with a wide variety of universe-types (possibly spanning a string landscape?) having different observable properties of nature;  possible generating mechanisms include chaotic inflation, colliding string-branes, and black holes.
      Level 3 — a "many worlds" interpretation of quantum physics proposes that each universe is continuously quantum-split into many independent realities with sequentially diverging histories;  but there are theological problems with Level 3;
      Level 4 — instead of a multiverse containing universes that can differ only in their initial conditions {in 1-2}, histories {in 1-2-3}, or low-energy observable effective laws of nature (for its dimensions, equations, physical constants, particle properties,...) {in 2}, in 4 the fundamental laws of nature also differ.   /   Tegmark says he would be bothered, for reasons I cannot understand, by "a fundamental, unexplained ontological asymmetry built into the very heart of reality, splitting mathematical structures into two classes: those with and without physical existence.  As a way out of this philosophical conundrum, I have suggested that complete mathematical democracy holds, that mathematical existence and physical existence are equivalent, so that all mathematical structures exist physically as well.  This is the Level IV multiverse.  It can be viewed as a form of radical Platonism."  Although he tries to defend the rationality of a claim that "mathematical existence and physical existence are equivalent," this seems silly and I don't think it can be rationally defended.  But the essence of Level 4 — the existence of universes with different fundamental laws — might be true (I think it is possible, although unlikely) without going to his Platonic extreme.
      A non-design explanation for fine tuning based on "beating the odds with a multiverse" can be plausible only if a multiverse contains many different universe-types with different laws of nature.  This variability-of-types occurs with Levels 2 (different effective laws) and 4 (different fundamental laws & thus different effective laws) but not with 1 (same effective laws, despite the differing initial conditions) or 3 (nothing differs except the divergent histories).


Can scientific evidence-and-logic help us distinguish between a universe and a multiverse?

      Universe or Multiverse? — Is there any scientific evidence?

      There is no direct observational evidence for a multiverse.  But according to most multiverse theories, other universes are in a different space-time framework so in principle they cannot be observed, or they are very far away so in practice they are unobservable.  Therefore, the fact that we do not observe any other universe does not count as scientific evidence against theories proposing the existence of many other universes.
      Can a multiverse theory be scientific? 
      Direct Evidence:  Because empirical testing is the foundation of scientific method but multiverse theories cannot be empirically tested using direct observational evidence, some scientists and philosophers claim that untestable multiverse theories are philosophical speculations rather than authentically scientific theories.  But could we have indirect observational evidence, now or in the future?
      Indirect Evidence:  The logical foundation of modern science is hypothetico-deductive logic, which permits a theory to propose unobservable entities if these help the theory explain observable outcomes, either by theory-based predictions (of future observations) or retroductions (of already-known observations).  This is why modern scientific theories proposing the existence of unobservable electrons (in chemistry) and ideas (in psychology) are widely accepted, because these theories — which propose that unobservable causes (electrons and ideas) help to produce the effects we observe — are the most satisfactory explanations for our observations.  Why is this relevant for a multiverse?  One possible mechanism for producing a diverse multiverse involves eternal chaotic inflation and string/M theory;  in various ways, each theory seems theoretically interesting and scientifically promising, but currently neither seems capable of being empirically tested, and both are incompletely developed theoretically;  but if these theories become useful in hypothetico-deductive logic, or in stimulating fruitful scientific research, and if the combination of these theories make a multiverse with diverse universe-types possible (or even probable), this would provide indirect observational evidence for a diverse multiverse.   Science and Unobservables
      Cause-and-Effects:  Maybe the cause of our universe also caused other universes, if our universe-mechanism and a multiverse-mechanism are related.
      Fine Tuning:  Evidence for fine tuning can be considered indirect evidence supporting the best explanation for the fine tuning.
      Naturalism:  If scientists demand methodological naturalism so they can propose only natural causes, and if a diverse-multiverse theory is currently the best naturalistic explanation for fine tuning, then it is now the best scientific explanation for fine tuning, whether or not it is true.  In this way, direct evidence for fine tuning is used as indirect evidence for a multiverse and against the divine design of our universe as a single-universe, although not against its divine design as a multiverse-universe.
      Simplicity, Parsimony, and Elegance:  Does a multiverse theory lack "simplicity" because it requires zillions of entities?   { Does a multiverse theory, or atomic theory, violate Occam's Razor? }
      Type of Explanation:  As described below in the second part of this section asking "is it scientific?", some scientists hope there is only one way for nature to be, while others prefer the diversity of a string landscape.

      A Delayed Conclusion — In my opinion, we should avoid claiming "it isn't science" if this claim is being used as a trump card to prematurely eliminate multiverse theories from serious consideration.  Instead we should be patient while learning what we can, and trying to infer what we can based on evidence-and-logic, even if these inferences cannot be proved.  Of course, we should use critical thinking to evaluate all theories, aiming for a logically appropriate confidence that is not too little, not too much.  When we do this for the current evidence-and-logic, in 2010, the arrogant overconfidence of many multiverse advocates is not warranted.  We should remember that multiverse proposals are informed speculations, not scientifically supported conclusions, so we should think "IF a multiverse exists in reality (not just in some imaginations), then..." and adopt a logically appropriate humility.

      String Theory as a Unified Theory of Everything?  The developers of string/M theory want it to be a unifed "theory of everything" that explains all of the known low-energy forces (electromagnetic, weak, strong, gravity) and elementary particles (quark-combinations and leptons) in a way that is consistent with our major theories, especially general relativity and quantum physics.  So far, M-theory cannot achieve these goals, but it shows promise, and some scientists (but not others) are optimistic about its potential.
      Metaphysical Humility:  Scientists should think of this goal as a Theory of Everything Physical (TOEP) rather than a Theory of Everything (TOE) because a unified scientific theory would not include the spiritual realm.  Theists believe that a spiritual realm does exist, so we claim that a scientific TOE would be incomplete so it's actually a TOEP.  Scientists should be metaphysically humble about their goals by explicitly acknowledging that their unified theory — if it's ever developed — might not describe everything.
      Two Types of Explanation 
      A Unified Theory with One Possibility?  Some scientists, especially those who are dedicated to finding non-theistic explanations for everything, are hoping that a unified "theory of everything" will show why it is necessary for the properties of nature to be what they are, because they think this would provide a materialistic non-design explanation for fine tuning.  But if scientists ever discover/construct a unifying super-theory that specifies a unique set of nature-properties (and this may not even be possible), wouldn't it be more rational to conclude — if there is only one way to combine all properties of nature into one set, and if this one set produces a universe that allows life — that our universe, operating as described in this elegantly unified theory, has been cleverly designed?
      A Unified Theory with Many Possibilities?  In contrast with hopes that a unified theory would explain why there is only one way for things to be (so they must be the way they are, and there is no need for design), with string theory the hopes for non-design depend on having many variations for the way things can be, in a string landscape of possibilities that provides a way to beat the oddsBut a multiverse would not prove non-design, because a mechanism that produces a diverse string-based multiverse might need to be intelligently designed.
      Types of Explanation and Philosophical Preference:  Some scientists are hoping that a unified theory will predict a unique set of nature-properties.  But other scientists prefer the diversity of string theory which predicts many possible sets of nature-properties, partly because this diversity might be useful in explaining the fine tuning of nature.  This philosophical preference, for one type of explanatory theory instead of another type, is one factor when we ask "Can a multiverse theory be scientific?" in this section, and in the tiebreakers for intellectual agnosticism below.


      Divine Design versus Materialism? — Philosophy not Certainty
No Proof or Disproof:  Why does the universe have properties that allow life?  I think the most plausible explanation, whether or not we live in a multiverse, is that our universe was designed and created by a divine designer/creator whose intelligence and power are far beyond our abilities to comprehend.  But this theory cannot be proved (beyond a reasonable doubt) by science or in any other way.  Alternative theories, proposing a non-designed multiverse, also cannot be proved or disproved.*  We cannot be certain about design or non-design, mainly because our evaluations are hindered by an absence of empirical data about what existed and what happened before the Big Bang Beginning of our universe.  And philosophical or theological objections to a multiverse are not conclusive.   {* In the future, maybe conclusive scientific evidence-and-logic will show that either a multiverse is impossible, or a multiverse is a necessary result of theories that are accepted.  But currently "the jury is still out" on this question. }
      In the beginning, ... :  Theistic and non-theistic worldviews propose descriptions of reality — and explanations for why and how things happen — that agree in most ways but differ in some important ways, including different ideas about what existed before the beginning of our universe or (if it exists) our multiverse.  A non-theist (atheist, pantheist,...) assumes the existence of a materialistic capability for creating our universe.  A theist assumes the existence of God, who has this creative capability.  Each asks the other, "Can you explain what caused the existence of what you assume as the starting point?"  Neither offers an answer that satisfies the other, and neither assumption can be proved, so theism and materialistic non-theism (atheism, pantheism,...) both offer an explanation that is possible but cannot be proved.
      Tiebreakers for Intellectual Agnosticism:  If non-design and divine design are both possibilities, and our questions about a multiverse (does it exist? would it be designed or undesigned?) cannot be decisively answered by scientific evidence-and-logic, our multiverse views can be strongly influenced by non-scientific factors, by our personal worldviews that include a religious view and its associated way of life, plus other factors that include philosophy of science (is a multiverse theory scientific?  what type of explanation do you prefer?) and philosophy of life (e.g. would you be bothered by "duplicates" in other worlds?), our individual psychology & community sociology, and more.

      Divine Design without Proof? — Worldviews and Faith

      Should this lack of proof bother a Christian?  No.  In fact, I think "a state of uncertainty" is the way God wants it to be, because a lack of certainty forces each of us — no matter what we believe in our personal worldview — to live by faith in what we believe.  What is the spiritual significance of this uncertainty, with humans apparently unable to logically prove or disprove the existence and actions of God?  Some interesting ideas to think about are briefly outlined in two sections (A Summary, Living by Faith) in a page asking Why isn't God more obvious?


Philosophy and Theology in a Multiverse
Philosophy:  Would a multiverse be compatible with conventional scientific rationality?
Theology:  Would a designed multiverse be compatible with traditional Christian theology?

      Wouldn't it be strange (for science and theology) if EVERYTHING happens?  —  4 rational principles
      A "strangeness" criticism of a multiverse — claiming that in a multiverse everything would happen, and that would be strange — is based mainly on philosophical preference rather than logic.  Here are some reasons to think we should say "wait a minute" and put the strangeness into perspective by thinking rationally:
     • Rational Principle #1 (physical possibility):  There are important differences between an immense multiverse (where MANY THINGS happen) and an infinite multiverse (where EVERYTHING happens).  The mathematics of infinity produces results that seem absurd in our normal non-infinite ways of thinking.  An argument based on converting these mathematical absurdities into philosophical absurdities will seem much less impressive when we think about the important differences between an infinite multiverse (which is physically impossible, and would be very strange) and an immense multiverse (which might be possible, and would be less strange).  Yes, the immensity would be unimaginably huge if, as proposed in chaotic inflation, the number of universes has been increasing exponentially since the beginning of inflation, continually growing by a factor of e (= 2.718...) every 10-37 second, but it would not be infinite.
    • Rational Principle #2 (actual experience):  If we imagine an omnipresent super-observer who is simultaneously EVERYWHERE and who thus can observe all of the many things that would happen in an immense multiverse, this super-observer might see some strange things.  But this would not occur with normal physical creatures like you and me, because we would observe things in the same way we do now, as one creature living in one universe.  The strangeness of a multiverse is only in your imagination;  in your actual experience, nothing would be different.
    • Rational Principle #2h (humility):  As a theological supplement to Principle #2, a humble theist should acknowledge that if God — who is an omnipotent super-observer, contrary to Principle #2 for creatures — understands the "many things" happening, and approves, that should be sufficient for us, whether or not we understand or approve.
    • Rational Principle #3 (theology):  An essential principle of Judeo-Christian theology is our claim that God is sovereign;  therefore, Christians should believe that in an immense multiverse the "many things" that happen would include only what God allows to happen.  Theists should not accept a non-theistic interpretation of a multiverse;  instead, we should formulate our own theistic interpretations.
      Let's apply these principles to the two questions for this section:

      Would a multiverse be compatible with conventional SCIENTIFIC RATIONALITY ?
      If we allow appeals to "beating the odds with a multiverse", will science be unreliable because scientists cannot reject a claim for any event, even if it seems extremely improbable, if the event might occur somewhere in an immense multiverse?  For example, will we have to accept implausible claims for a "perpetual motion machine" that violates the probability-based Second Law of Thermodynamics?
      No.  To see why, let's look at what a diverse multiverse might do, and what it would not do:
      We might consider "beating the odds" to be a valid logical argument for only one type of scientific question — when we ask about ingredients of reality (such as life-allowing properties of nature, plus a life-producing history) that would be necessary for our existence — because only in this case could anthropic selection (*) provide a logical reason to reject a probability-based scientific claim for an intelligent design of nature before history began, or for intelligent design-action during history.  For these questions about anthro-essential design, if scientists ever conclude that any stage in a natural process leading to humans (in the properties of nature, initial origin of life, or life's evolution into humans) would be extremely improbable without intelligent design, thus making design seem probable, their probabilistic logic might indicate that they should propose two if-then conditional conclusions:  • IF we live in a single universe (or even a moderate-sized multiverse), then a claim that "design seems probable" is scientifically supported;  • but IF we live in an extremely large multiverse, then scientists can remain agnostic by saying "we don't have the certainty of indisputable scientific evidence either for or against design" because a multiverse could be either designed or non-designed (as explained earlier) and because a claim for design-action cannot be scientifically proved (due to "beating the odds" logic) or disproved (perhaps there are not enough universes to beat the highly unfavorable odds and produce the observed feature; and science cannot evaluate the possibility of undetectable natural-appearing design-directed action).
      For all other scientific questions, scientists should logically conclude that "the best way to bet" is governed by the principles of their science.  Why?  Because, as stated in Principle #2, scientists in a multiverse would not be omnipresent super-observers;  they would live in a single universe, and in every universe, whatever is most likely to happen is what is most likely to be observed.  Therefore, in any universe-type where nature is reliable (where natural process is consistent, as in our universe) science can be based on "the best ways to bet" and it will be reliable, because scientists will not observe frequent highly improbable events (on a "tail" of a probabilistic distribution) that would threaten confidence in their science.  We have no reason to think that "tail of the distribution" events — such as perpetual motion machines (defying the Second Law) or wingless flying pigs (defying gravity) or everyday improbabilities such as Aunt Bertha winning 20 consecutive state lotteries — would be more probable in other universe-types with science (if they exist) compared with our universe-type.  And we can imagine some events (such as wingless pigs flying around the world?) so improbable that they would NEVER occur in any universe, even in an extremely immense multiverse.  Our own science can continue as usual, based on our own universe-specific observations, whether or not we live in a multiverse.  And all actualized-universes of the same universe-type (if different types and actualizations really exist) should develop the same basic scientific principles, although in actualized-universes the differences in initial conditions would lead to different details in their histories of nature, and differences in worldviews-and-culture would produce some variability in the formulations of these principles.  But if more than one universe-type has intelligent beings and science, each distinct universe-type will have different scientific principles.

    * With anthropic selection, what is being selected?  It depends on the perspective:   • From our viewpoint the observations are selected, because "we must observe a universe that is consistent with our existence" so the type of observaions we can make (i.e. the universe we can observe) is selected-for by the fact of our existence.*    • But from the viewpoint of an omnipresent super-observer (if a multiverse exists, and if such an observer exists) there is a selection for observer-AND-observations, because both can exist only in a universe that is consistent with the observer's existence.
    * An observation-selection effect, restricting the type of universe we can observe, applies to everything we observe.  The Anthropic Principle is called anthropic because we humans are the observers, but the essential logic involves WHAT we observe, not WHO is observing.  For example, a logically analogous Kangaroo Principle states that the properties of nature in our universe must be consistent with the existence of kangaroos, because we observe them.
    exceptions?  —  If super-natural miracles occur, our observations of these miracles would not be logically constrained by The Anthropic Principle, because we're observing supernatural process, not natural process.  

      Would a designed multiverse be compatible with traditional CHRISTIAN THEOLOGY ?
      I think the answer is "yes" because imaginary theological problems don't seem to be actual theological problems for Bible-based theology.
      Is it a theological problem if we can imagine strange situations, such as a "duplicate" of you (with the same DNA) living in another universe within a multiverse?  No, this is not a problem, for three reasons:
      First, remember Principle #1 (above) and ask, "Would duplication be an actual problem, or only an imagined problem that occurs only in imaginative speculations about ‘everything’ happening in an infinite multiverse?"
      Second, remember Principle #2.  Even if duplicates exist, this would not be a theological problem because each person (you and the genetic duplicate) would be living independently — with no knowledge of the other person — in different universes, and God would hold each of you morally accountable for the way you live, for your decisions and actions in your own here-and-now situations.  This would be similar to identical twins (having the same DNA) living in our world now, which causes no theological problems because God holds each twin accountable, as an individual person, for the way they live.  If identical twins are not a problem for God (if He "approves" and loves these people, as in Principle #2h) then we should not consider twins to be a theological problem;  and if actual twins are not a problem, potential duplicates are also not a problem.   /   In the Level 3 multiverse proposed in a Many Worlds Interpretation of quantum physics (MWI), history constantly diverges in many branches, and the here-and-now principle fails because you could say "yes" to salvation in one branch, but "no" in another branch, so which history would be the YOU that is being judged by God?  Also, by definition MWI seems to deny the possibility of divine control, so in some branches uncontrolled evil and suffering would occur.  These would seem to be genuine theological problems, from our perspective, but from God's perspective they might not be problems.  And a Level 3 multiverse is speculative;  I think it does not exist in reality, and if it doesn't exist it won't cause any problems.  For a more thorough discussion of MWI, click the end-of-section link (for my responses to Robert Mann) and search for quantum.
      Third, remember Principle #3.  Judeo-Christian monotheists who believe the Bible will believe that God is sovereign.  We should reject a non-theistic interpretation of a multiverse.*  Instead, when we think about "many things happening" we should view this as "only things allowed by God" because God has sovereign control over everything that occurs in everything He has created.  If God created an immense multiverse, He could decide that life will exist on only our Earth — and He could achieve this goal either by miraculously creating life only here (if life cannot evolve naturally) or by instantly "killing the life" whenever it does naturally evolve on any other planet — and this is what would occur, no more and no less;  or God could also create life, or allow life, in other places in our universe, or in more than one universe, perhaps in an immense number of universes.  And whatever God decides — whether it's life only on Earth, or also on other planets, or also in other universes — that is fine with me, and is compatible with what the Bible teaches.
      * theistic interpretations of a multiverse are analogous to theistic interpretations of evolution:  Although non-theists can claim that "natural = without God" for natural neo-Darwinian evolution, this is not the way "natural" should be viewed by Judeo-Christian theists.  Instead, we should define natural process as being designed, created, sustained, and guided (occasionally or continually) by God.   Is evolution unsupervised? NABT and Biology-Theology   Is "theistic evolution" an impossible combination? (What can a Christian believe about evolution?)
      If we remember the rational principles of thinking about a multiverse, we'll see that claims for theological problems involve only a conflict with personal philosophical preferences, not with essential Bible-based theology.

note: Most of the ideas in this section, about the philosophy and theology of a multiverse, were stimulated by my responses to a paper by Robert Mann.



If you're curious, some questions in this page are examined in more detail in Part 2 which is an earlier less-condensed version of some parts of this page.  Or you can look at pages by a wider variety of authors in the links-page for INTELLIGENT DESIGN OF THE UNIVERSE.

      The Properties of Nature depend on its Characteristics, Constants, and Conditions:

      qualitative CHARACTERISTICS — time and 3-dimensional observable space, energy/matter in elementary particles (quarks in protons, neutrons, ... plus electrons and many more), + and - charge, photons of light, wave/particle duality and resulting quantizations, Pauli Exclusion Principle, four low-energy forces (electromagnetic, weak nuclear, strong nuclear, gravitational), 3-dimensional physical space, and causal relationships such as those formulated by Newton, Faraday, Maxwell, Einstein, ...
      numerical CONSTANTS — Some important features of these characteristics depend on physical constants, such as those for the strength of forces, Planck's Constant for the quantization of energy, the charge and mass for each particle, cosmological constant, ...
      initial CONDITIONS — The current state of the universe also depends on its initial quantum fluctuations, initial amounts and spatial distributions of matter-and-antimatter, initial rate of expansion, ...

      Four Types of Intelligent Design — Definitions

      These two excerpts are from INTELLIGENT DESIGN IN SCIENCE & SOCIETY:
      Some disagreements about design are unavoidable because people just disagree.  But in debates about design some of the "more heat than light" is due to confusion about definitions of design.  This is partly due to ignorance, when people don't think about what they're saying.  But some confusion seems intentional, when debaters (on both sides) think distortion will help them appeal to listeners they want to impress.  Do you think confusion should be minimized?  If so, then we should define different types of "design" so we can distinguish between them, so we can think and speak with more clarity.  .....<snip>.....
      When scientists study a feature of nature (a star, bacteria, whale, biochemical system, radio signal, house, car,...) they can ask about its origin.  Was it produced by intelligent design, by:
      • natural process because, before history began, the universe was designed so this would happen;
      • natural process that was supernaturally guided in an undetectable natural-appearing way to produce a particular natural-appearing result that was wanted, or
      detectable design-directed action by a supernatural agent (•) or natural agent (•), which was necessary because undirected natural process would not produce the feature;
      or maybe there was no design, and the feature was produced by natural process that was not designed, not undetectably-guided, and not detectably-directed.

Beating the Odds to Neutralize claims for Intelligent Design
By combining the principle of anthropic selection with an appeal to "beating the odds" in a multiverse, any science-based claim for intelligent design that was necessary for the observer's life can be logically neutralized, whether the claim is for a design of the universe before history began, or for design-directed action during history.

      The argument for "beating the odds" is simple:  if enough universes exist, extremely improbable events will happen.  For example,...

      Odds for Poker
      To understand the concept of probabilistic resources, think about a five-card poker hand and the high odds against getting a royal flush (10-J-Q-K-A of same suit);  the probability of this happening is 1 in 649,740.  But with 450,365 deals (= 649740 x .693146853)* your chance of getting a royal flush is 50%, for 1-to-1 odds.*  And as the number of dealing opportunities increases, your odds improve dramatically:  with 2.25 million deals (only 5 times the 50% break-even number) the odds are 31-to-1 in your favor, because for every 32 sets-of-deals (25 = 32) you will get a royal flush 31 times while failing only once;  and with 9 million deals (only 20 times the break-even number) the odds are a million-to-one in your favor!    [* The multiplying factor for "breaking even" is .693146853 because "(649739/649740)(.693146853)(649740) = .500000000" which is the probability of not getting a royal flush after 450365 deals.]     {* I hand-calculated everything in this paragraph, using a simple TI-30 calculator.}
      an important concept:  This example shows that the available probabilistic resources (or probabilistic supply) — which is an important factor that must be included when we calculate the probability that an event will occur — increase when the number of poker hands increases;  these resources would also increase in a multiverse.

      Supply versus Demand — comparing Probabilistic Resources with Probabilistic Requirements
      There are important differences between an immense multiverse (where MANY THINGS happen) and an infinite multiverse (where EVERYTHING happens).  Using the bizarre math-of-infinities, it's easy to claim that “with an immense multiverse EVERYTHING would happen.”  But an infinite multiverse is physically impossible.  The math-of-immensities is much less simplisitc.  So... for an immense multiverse, how might we estimate the "many things" that could happen?  A credible math-of-immensity is much less simplistic than the math-of-infinity.  Here is an outline of a basic mathematical approach to immense Supplies and immense Demands:
      • estimating Probabilistic Supply:  With an immense multiverse — produced, for example, IF cosmic inflation continually causes rapid branchings of bubble universes — the Probabilistic Resources (= Probabilistic Supply) would be extremely immense, but not infinitely large.
      • estimating Probabilistic Demand:  To produce a “duplicate of you” — as one part of the “everything happening” that is often claimed — would require a very improbable sequence of events during the history of a universe, with a cosmic evolution (to produce stars/planets/etc) plus biological evolution (to produce humans with DNA) that will produce a human with the same DNA (with the same atoms combined in same number of base-pairs, on same number of chromosomes, etc);  the odds-for-this would be extremely small, so the Probabilistic Requirements (= Probabilistic Demand) would be extremely immense, but not infinitely large.   {Often a person talking about a duplication-scenario imagines their own duplicate giving a speech (that is identical in all ways, or is changed in some ways), which would require similar societal developments and life-histories, etc, and thus a much higher Demand.}     { Why should we say “so what” to concerns (philosphical or theological) about potential duplicates? }
      •• comparing probabilistic Supply versus Demand:  To estimate the odds-for-duplication in an immense (but not infinite) multiverse, we would have to estimate the Resources/Supply (it's immense) and compare this with an estimate for the Requirements/Demand (it's also immense).   /   The process of plausibly estimating a Probabilistic Demand would be very complex and extremely difficult, and it would be MUCH more difficult to get a plausible estimate for Probabilistic Supply.
      Currently, as I'm writing this in early 2016, I don't know if this kind of math-estimate has been done.

      Here are two important concepts, regarding universe-types and universe-actualizations:
      • A plausible "beating the odds" non-design explanation for the fine tuning of nature in a life-allowing universe (to oppose a claim for intelligent design that occurred before the history of our universe began, which is the main focus of this page) requires a multiverse with an immense number of universe-types whose nature-properties span a wide range.     (note: For this, the number of universe-actualizations for each universe-type would also be a minor factor to consider, for life to not just be allowed but to actually occur.)
      • A plausible "beating the odds" non-design explanation for features-of-nature produced during the history of our universe (to oppose a claim that a particular feature, such as the first living organism, was produced by intelligent design-directed action instead of by totally natural evolution) would be helped by a multiverse with an immense number of actualized-universes of the universe-type where the feature occurs.     (note: For these questions, the number of universe-types that are life-allowing would also be a minor factor to consider.)

      Odds for Life
A claim for intelligent design of a life-feature, or anything else, can be made by claiming that the feature was produced by natural process because (before history began) our universe was designed so this would happen, or that (during the history of our universe) the feature was produced by design-directed action rather than undirected natural process.  At either stage, before history or during history, a combination of observer-selection plus multiverse can "explain away" all evidence for intelligent design if this design was necessary for the observer's existence.
      For example, imagine that the probabilities are 10-400 for a life-allowing universe, and then 10-2000 for a natural origin of life within such a universe, and 10-1 for the subsequent biological evolution (and relevant cultural history, etc) of a life form with the capability to recognize fine-tuning and formulate the anthropic principle, so the overall probability is 10-2001 (= 10-2000 x 10-1) for the second stage of a process leading to anthropic observers, such as me writing this page and you reading it.  {note: These imaginary probabilities are not intended to be accurate estimates, they are just numbers I've assigned to illustrate the logic of a "beating the odds" argument.*}  In this situation, with probabilities of 10-400 and 10-2001 for the two stages, for the first stage if there are 10402 types of universes — and if their properties are "randomly distributed" as in dealing cards — the odds will be 1043-to-one in favor of getting at least one type of life-allowing universe.  And for the second stage, for what happens during history, if there are 102003 actualizations of this universe-type, the evolution of anthropic observers becomes a statistical certainty with odds of 1043-to-one favoring it.
      Due to our lack of experience, it's difficult for humans to understand the huge size of these numbers.  We're unable to visualize 1043 in a way that is intuitively meaningful;  10402, 10500, and 102003 are much larger but are not infinite.  Similarly, we cannot intuitively appreciate the tiny size of numbers like 10-400 or 10-2001.

      Life can occur without intelligent Anthropic Observers, and this happened for billions of years on our earth before humans arrived on the scene and, in the past few decades, discovered the fine tuning of nature.  If living creatures are intelligent enough to recognize the fine tuning that allows their existence, their universe will seem "special" to them;  but if the creatures are less intelligent, their universe would still be special and rare, even if they don't recognize this rarity.

      * An Opportunity for Humility in Life-Sciences:  Scientists who are confident about a total evolution of life — including its chemical origin and subsequent biological evolution — will think "beating the odds with a multiverse" is necessary only for the first stage (in pre-history) to get a type of life-allowing universe.  They think that only one actualized universe of this type will be necessary, because a life-allowing universe is also a life-producing universe in which life and intelligent observers will always develop by natural evolution.  But the option of appealing to "multiple actualizations of this universe-type" is available, so they have the freedom to be humble about the natural sufficiency of life-production in any aspects of life science (especially for the initial origin of life, but also for evolutionary biology) if they ever think some humility is warranted.
      A Possible Cause for Concern in Life-Sciences?  If we allow appeals to "beating the odds" when investigating a claim for intelligent design that was necessary for life, will we have a reason to doubt the scientific credibility of a negative conclusion (that there was no design) based on the odds-beating appeal?  This question is examined in Multiverse and/or Intelligent Design in Life-Sciences.

      Motivations to Propose or Oppose a Multiverse:  Theists who want to "win arguments for God" by their claims for divine intelligent design (before or during history) will be motivated to oppose a multiverse that can "neutralize" their claims for design.  And non-theists who want to avoid losing these arguments will be motivated to propose a multiverse;  they will defend it vigorously if they think it is necessary to maintain their worldview-beliefs;  a multiverse seems necessary for non-theism, but (since a multiverse might be divinely designed) it would not be sufficient as a proof of non-theism, or even to provide evidence for non-theism.  By contrast, theists who are not concerned with winning arguments can say "either way is fine, with a universe or multiverse."  They, and others who mainly just want to find truth, will try to evaluate the pro-and-con arguments — scientific (based on evidence and/or theory), philosophical, and theological — using unbiased logic, although reducing bias is difficult because none of the arguments seem conclusive so "our multiverse-views [to reject or accept it, and think of it as undesigned or designed] can be strongly influenced by our personal preference for a particular worldview and its associated way of life."

      Appropriate Humility — with a confidence that is not too little, and not too much — is a worthy goal and a useful attitude.  This important concept is explained by Bertrand Russell: "Error is not only the absolute error of believing what is false, but also the quantitative error of believing more or less strongly than is warranted by the degree of credibility properly attaching to the proposition believed, in relation to the believer’s knowledge."

      Scientific Simplicity and Occam's Razor
      Does a multiverse theory lack the simplicity and elegance often associated with a good theory?
      One statement of scientific simplicity, Occam's Razor (aka Ockham's Razor), says "one should not increase, beyond what is necessary, the number of entities required to explain anything."  Does a multiverse theory, which proposes an immense number of entities, therefore lack simplicity and elegance?  Not necessarily, because there is a difference between the number of types of entities and the number of entities.  If a multiverse theory has a simple logical structure (in its proposals for types of entities and their relationships), it should not be criticized just because it proposes a large number of physical entities (zillions of universes), for the same reason that atomic theory is not criticized for proposing that 1025 atoms (more than a million billion billion) are in a cup of water.
      Our main criterion for evaluating scientific simplicity should be the logical structure of a theory.  For example, a theory with 400 adjustable parameters (so it can explain 400 experiments) will be viewed with suspicion by scientists because it is not simple-and-elegant.  Instead, it seems to be "an inelegant patchwork of ad hoc components that have no apparent function except to achieve empirical agreement with known data." {quoted from my Integrative Model of Scientific Method which explains how "simplicity" can be useful for theory evaluation}
      Regarding theory structure, Victor Stenger explains: "Some theologians and scientists dismiss the notion [of a multiverse] as a gross violation of Occam's razor.  It is not.  No new hypothesis is needed to consider multiple universes.  In fact, it takes an added hypothesis to rule them out — a super law of nature that says only one universe can exist.  But we know of no such law, so we would violate Occam's razor to insist on only one universe."
      Also, we should remember that Occam's Razor is only a secondary strategy, used for comparing theories that already have been judged to be satisfactory in other ways, especially in the reality checks that are the logical foundation of scientific method.  We should not assume "the simpler theory is probably correct" because this assumption is often wrong.

      Four Definitions of Anthropic Principle

      Although the basic logical principle was proposed earlier, the term "anthropic principle" was introduced in 1973 by Brandon Carter.  Later, distinctions were made between four anthropic principles: Weak and Strong (by Carter), Participatory (John Wheeler), and Final (John Barrow & Frank Tipler, 1986, in The Anthropic Cosmological Principle).  Because many versions of the anthropic principle are defined in different ways by different people (4 definitions are below, and for details check Wikipedia) when someone says "anthropic principle" or "anthropic reasoning" without defining it, their meaning is not clear.  In this page the anthropic principle is a simple statement — "because humans exist, we must observe a universe consistent with our existence" — that is logically valid (*) but does not support either design or non-design, and does not explain why our universe is fine tuned for life.  Other definitions, claiming more than this, can be speculative and controversial, so when this term is used elsewhere you should try to determine the intended meaning.   /   * A life-allowing universe is logically necessary, so we must observe it, only if natural process (not a supernatural "continuous miracle") is maintaining our lives;  this is the assumption of most people, including me, and science seems to show that natural process is sufficient to maintain life.
      Here are definitions quoted from Barrow & Tipler, plus my comments.
      WEAK Anthropic Principle (WAP):  "The observed values of all physical and cosmological quantities are not equally probable but they take on values restricted by the requirement that there exist sites where carbon-based life can evolve and by the requirements that the Universe be old enough for it to have already done so."   ( Notice their naturalistic assumption that the universe must be not just life-allowing but also life-producing so "carbon-based life can evolve." )
      STRONG Anthropic Principle (SAP):  "The Universe must have those properties which allow life to develop within it at some stage in its history."   ( So... does SAP propose an intelligent design of our universe?  Does it claim that a multiverse is impossible, since most universes in a multiverse would not have life? or would their SAP-requirement apply only to the multiverse as a whole, by claiming that a multiverse without life is impossible?  Wikipedia says that prominent philosophers, John Leslie and Nick Bostrom, "reject the Barrow and Tipler SAP as a fundamental misreading of Carter" whose definition focuses on the selection effects due to the presence of observers. )
      PARTICIPATORY Anthropic Principle (PAP):  "Observers [who eventually must emerge during history] are necessary to bring the Universe into being."   ( This theory is based on a wildly speculative mystical interpretation of quantum physics, claiming that an act of "observation" produces reality, so "if no observers then no reality."  This bizarre mystical speculation is not supported by the science of quantum physics, as you can see in Philosophical Interpretations of Quantum Physics which explains why "oops, they used a bad word," and why, when we ask "Do we create reality?" you must arrogantly answer "yes" — for 13.7 billion years of previous history! — if you want to believe that the Participatory Anthropic Principle is true. )
      FINAL Anthropic Principle (FAP):  "Intelligent information-processing must come into existence in the Universe, and, once it comes into existence, it will never die out."   ( They also claim that, according to FAP, life will evolve toward an Omega Point when "the totality of life... is omnipotent, omnipresent, and omniscient" in a pantheistic version of God.  In a perceptive evaluation that seems accurate, Martin Gardner calls this the Completely Ridiculous Anthropic Principle, CRAP.  I agree with Gardner;  we should not believe that life will evolve into something with the characteristics that theists attribute to God, and that life can never end. )  (Wikipedia says, "In fairness to the authors, they state at the outset that they are not necessarily committed to the ideas they describe, and admit that the SAP and FAP [but not the arrogantly delusional PAP?] are ‘quite speculative.’")

this page is

copyright ©2003 by Craig Rusbult, all rights reserved,
with the most recent revision in 2010

Throughout this page you'll find links for related pages by me.
And for a quick overview plus related pages by other authors,
And more generally,
homepage and sitemap for Questions about Origins
and homepages for Whole-Person Education
and the American Scientific Affiliation.