Does the Anthropic Principle Explain the Fine Tuning of the Universe?

Post Author: Bill Pratt

One of the most fascinating discoveries of modern science has been that the universe is finely tuned to support human life.  Philosopher of science John Lennox, in his book God’s Undertaker, notes that “this perception on the part of scientists, that the universe has to be very precisely structured in order to support life, has been called the anthropic principle.”

Christian theists argue that this fine tuning calls for an intelligent creator of the universe as an explanation.  How do non-theists respond to the fine tuning of the universe?

Lennox explains:

Some scientists and philosophers maintain that we ought not to be surprised at the order and fine-tuning we see in the universe around us, since if it did not exist then carbon-based life would be impossible, and we would not be there to observe the fine-tuning.  In other words they use the anthropic principle against the inference of design.  In fact, Richard Dawkins in The God Delusion tells us that the anthropic principle and God function as alternative explanations.

One response, then, to fine tuning, is to say that we should not be surprised at fine tuning because if there were no fine tuning to explain the origin of intelligent observers, then we would not be alive, as intelligent observers, to observe the fine tuning.  Does this really explain anything, though?  This explanation seems like a sleight of hand, or no explanation at all.  Lennox reveals why we feel this way:

All the anthropic principle does is to tell us that for life to exist, certain necessary conditions must be fulfilled.  But what it does not tell us is why those necessary conditions are fulfilled, nor how, granted they are fulfilled, life arose.  Dawkins is making the elementary mistake of thinking that necessary conditions are sufficient.  But they are not: in order to get a first class degree at Oxford it is necessary to get into the University; but, as many students know, it is certainly not sufficient.  The anthropic principle, far from giving an explanation for the origin of life, is an observation that gives rise to the need for such an explanation.

One of the easiest ways to see that the anthropic principle, by itself, is not a sufficient explanation, is by reviewing an illustration given by philosopher John Leslie.  He says that using the anthropic principle against the design hypothesis

sounds like arguing that if you faced a firing squad with fifty guns trained on you, you should not be surprised to find that you were alive after they had fired.  After all, that is the only outcome you could possibly have observed – if one bullet had hit you, you would be dead.  However, you might still feel that there is something which very much needs explanation; namely why did they all miss?  Was it by deliberate design?  For there is no inconsistency in not being surprised that you do not observe that you are dead, and being surprised to observe that you are still alive.

Rather than give an explanation of the fine tuning of the universe, the anthropic principle merely invites us to ask for a real explanation.  I think we would all like to know why all 50 people in the firing squad missed us.

  • Todd

    “How do non-theists respond to the fine tuning of the universe? …” – strawman constructed by Bill.

    “ … I think we would all like to know why all 50 people in the firing squad missed us.” – strawman still standing.

  • Todd,
    This is the exact argument that Dawkins uses, so are you saying that Dawkins is himself a caricature (or strawman) of atheism? If that is the case, then why is he such a hero to so many atheists?

  • Todd

    Bill,
    Perhaps you are correct that the argument is not a complete strawman, but you present it in the post as how “non-theists respond to the fine tuning of the universe.” Perhaps I would take less exception if you posted it as how Dawkins responds in his book.

    However, I think Dawkins point still stands that the anthropic principle is an alternative explanation of why the cosmological constants are what they are. On the one hand, we can suggest that there is a god or “knob twiddler” as Dawkins puts it that tuned the cosmological constants just right to support life. There is, as always when god is suggested, no proof for this premise aside from conjecture. The anthropic principle offers the explanation that the cosmological constants have the life sustaining values, because if they were values that were not life sustaining, we would not be here to observe them. The reason this is not a satisfying answer is because the question “why are the values of the cosmological constants the values that they are?” is not a rational question. They simply are because they cannot be any other way. The anthropic principle just states the obvious. To draw the conclusion that god exists because cosmological values cannot be any other value than what they are seems absurd to me.

    Looking at your firing squad analogy; if the firing squad were to only fire once at a single person, it would be unlikely they missed and in fact a strange coincidence. But even that does not necessitate someone designing the miss. If we were to modify the scenario, one might not be surprised to be alive if they knew that they were to be one of a trillion executions performed and that perhaps the squad might completely miss every now and then. Similarly, Dawkins says in The God Delusion, “If the odds of life originating spontaneously on a planet were a billion to one against, nevertheless that stupefyingly improbable event would still happen on a billion planets. The chance of finding any one of those billion life-bearing planets recalls the proverbial needle in a haystack (back to the anthropic principle) and beings capable of looking must necessarily be sitting on one of those prodigiously rare needles before they even start to search.”

    Aside from the anthropic principle, I find myself and Dawkins in agreement on another point regarding the idea of fine-tuning. I found this quote from Dawkins in his eulogy of Douglas Adams, which is closely in line with my last post on the subject that when we look at the universe through the lens of time, it is not an environment built for human life, he says more eloquently:
    “… imagine a puddle waking up one morning and thinking, ‘This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn’t it? In fact it fits me staggeringly well, must have been made to have me in it!’ This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it’s still frantically hanging on to the notion that everything’s going to be all right, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.”

  • Boz

    Bill Pratt said: “One of the most fascinating discoveries of modern science has been that the universe is finely tuned to support human life.”

    I don’t think this is accurate to say.

    The fine-tuned universe is the proposition that the conditions that allow life in the Universe can only occur when certain universal fundamental physical constants lie within a very narrow range, so that if any of several fundamental constants were only slightly different the universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood.

    fine-tuning refers to circumstances when the parameters of a model must be adjusted very precisely.

    We don’t know the allowable ranges of the universal constants. It might be that there is only one possibility. Or an infinite range of possibilities. Or anything in between. We just don’t know.

    For example, the fine-structure constant is 1/137.035999074. (maybe). We don’t know the allowable range, so we cannot assert that this value is fine-tuned for human life.

    Asserting that the fine-structure constant is fine-tuned implicitly asserts that it has a wide allowable range. This implied assertion has not been demonstrated to be true.

    (incidentally, this argument feels like confirmation bias, but it also looks sound. #FirstWorldProblems)

  • Andrew Ryan

    To me the more accurate ‘shooting’ analogy is the sharpshooter fallacy. We’re talking about hits here, not a bunch of misses – with the ‘hit’ being ‘the right scenario to allow life’. In the sharpshooter fallacy we take a wall punctured with holes and we draw targets round them, saying ‘Look, the targets have been hit’.

    The point is that the ‘goal’ has been asserted after the fact.

    Humans could say “The world was set up to allow ape-like creatures to rule”. A different run of evolution might have seen smart lizards in charge, figuring it could have been no other way. We could imagine a thousand different ways evolution could have gone, with different creatures dominating – many wouldn’t even have the intelligence or self-awareness to imagine it was a deliberate result – but they’d be wrong if they COULD think it.

    Now, instead of thinking ‘We’re in charge, that must be deliberate’, change the thought to simply ‘We’re alive and self-aware, that must be deliberate’. isn’t this still the same principle of drawing the target after the fact?

    Imagine there are a thousand different ways the universe could be to sustain intelligent life. For each one, we can imagine a lifeform saying “The universe is set up perfectly for US. It must be deliberate”. I think we can all agree that each would be wrong – they would be indulging in Douglas Adam’s fallacy of the puddle. Just because THEY are the life the universe has produced, doesn’t mean the production of them was deliberate, or the universe’s ‘rules’ were made just for them.

    Now, if we re-jig that so that that there are still a thousand different ways to allow life, but only a couple of them lead to INTELLIGENT life, then obviously only two scenarios would lead to lifeforms saying “It’s deliberate” – by definition the other 998 wouldn’t be able to think it. But if they COULD, they’d be wrong too.

    Now, re-jig it again – imagine we have a thousand different ways the universe could be, and only ONE allows intelligent life – why is it any less of a fallacy for the life in that one scenario to say “It must be deliberate”?

  • Andrew,
    It seems to me that when scientists look at the laws and constants that govern the universe, they see that if these laws and constants were changed even a little, life could not exist. This is a truly surprising result. Why? Because it seems much more likely that the laws and constants should be able to change a lot and that life would still exist regardless.

    If you think of each of one of the fine tuning elements as a knob on a giant universe making machine, then each of the knobs has to be in a precise position relative to all the other knobs for life to come into existence. If we spin the knobs around and we try out all kinds of other combinations, then we get no life. This is highly unexpected and certainly not intuitive.

    What scientists have expected to find is that the knobs could be spun around into just about any old position, and all of those positions would support life, but that is exactly the opposite of what the case is.

    Surely the fact that only one precise combination of the knobs produces life begs for an explanation. This just seems so obvious to me.

  • But the puddle hasn’t found physical constants and complex forces of nature that are balanced on a razor edge, has it? It’s not just that we humans look around and say, “Wow! The earth is warm and provides us food. The universe was finely tuned!”

    No. It’s far more incredible than that. Here is one example of the fine tuning:

    “Many have estimated that the cosmological constant—a fundamental number that governs the expansion rate of empty space—must be precisely set to one part in 10 to the 120th power in order for life to occur; if it were too large, the universe would have expanded too rapidly for galaxies and stars to form, and if it were too small, the universe would have collapsed back on itself.”

    Comparing this kind of precision to a puddle on the ground just isn’t convincing. The analogy doesn’t work.

  • Todd

    Bill,
    I think you are getting the two concepts confused. The analogy of the puddle is simply how to look at life over time. To say that the hole was designed for the puddle is not a true statement because over the course of time, life evaporates.

    Your analogy of the cosmological constant points again to the anthropic principle. That conststant simply is that value. To engage in ‘what if it were different’ and then infer design from the consequences is not a rational argument.

  • Anonymous

    The anthropic principle is based on the same reasoning that makes casinos rich: misunderstanding probabilities. It’s looking at the problem of ‘tuning’ from the wrong end where the odds are long against it; instead start with what is.

    What are the chances that this lottery winner won? The probability is 1. It happened. No matter how unlikely it may be from the front end, no matter what the odds might be calculated that the lottery winner turned out to be the lottery winner before the draw , the result is now assured; this ticket, and this ticket alone, was the winning ticket. This universe and this universe alone is the winning ticket regardless of how unlikely we calculate how unlikely it turns out to be.

    Those who wish to use unlikeliness to suggest agency are not thinking straight. For example, if you tried to calculate the probability of you being you right this instant, starting from the first sperm out of tens of millions to fertilize the egg from which you developed, and factored in all the probabilities of survival from that moment until now, all the necessary and formative experiences you underwent, you might be surprised at how unlikely the chances are for you to be reading this… perhaps somewhere in the vicinity of one chance out of a trillion trillion trillion. How can such a slight probability be made manifest without divine agency?

    The answer is all around you: billions of such slight probabilities have become manifest in every human being there is, was, or shall be. In fact, the odds are just as long if not more so for many other life forms here on earth.

    Let’s extend the point. What are the probabilities that all life is exactly the way it is right at this moment? The result is a probability of 1. It is. But the calculation for taking all variances that could have produced a different result means multiplying all the trillions of trillions of trillions to one by each and every life form on earth. Yet here we are. Here they are. The chances are almost at zero when measured from the front end but assured when measured from the final result. And that’s the key point: almost. In that word lies exposed the false assumption believers in the fine tuning argument hold… that ‘almost’ means something along the lines of ‘therefore Jesus’, or ‘therefore Allah’ or therefore Shiva. But in not one single case is there good evidence for divine fine tuning – not in your life, not in mine, not in the geranium in the old apartment. This is the way life is here on earth, the way life has become, subject to understandable natural forces and process over time. For these we have remarkably good evidence overlapping in every line of inquiry we follow… except in much of theology that presumes the need for a divine lottery commander, a divine erosion commandant, a divine evolutionary engineer.

  • John Lennox is a genius

  • IntelligentAnimation

    Andrew, you misapplied the sharpshooter fallacy, although that is a fallacy often referenced in anthropic principle arguments. Just because Bill used an analogy with guns doesn’t mean he was talking about an after-the-fact drawn target. He did no such thing, at least not with his analogy.
    He was refuting Dawkins’ foolish argument disputing the AP because otherwise we wouldn’t be here to observe it. Bill could have as easily put his subject at ground zero of a nuclear bomb detonation, coming out unscathed. It would be a reasonable question for him to ask why he survived. To dismiss his question as silly because otherwise he wouldn’t be around to ask it, is nonsensical reasoning.
    Likewise it makes perfect sense to question why life exists considering the fine tuning needed for it to do so. To say “Otherwise we wouldn’t be here!” dodges the important questions at hand.

  • IntelligentAnimation

    tildeb, actually you are precisely the kind of gambling expert the casinos love to invite to their establishments.
    What if someone wins the lottery each and every week for a couple of years with one ticket per week. Do you still say that it is foolish to ask why they are able to do that? Do we still say “hey, it just is.”?
    It makes perfect sense to question how something happened if it is statistically impossible. It makes no sense, knowing the odds against something happening by luck are infinitesimal, to claim it happened by luck.
    Apply that last paragraph to your biological analogy and you see why Darwinists are so foolish as well.
    See if you can see the difference between these two statements:
    “What are the odds that X exists by chance?”
    “What are the odds that X exists?”
    You are foolishly claiming that the answer to the second question must also be the answer to the first and that is blatantly incorrect. There can be other explanations besides chance, and if the odds are prohibitive, a non-chance explanation becomes a virtual certainty.

  • IntelligentAnimation

    Dawkins thinks the odds of life forming on earth by chance are a “stupefying” one in a billion? Not in his wildest dreams are the odds that possible.

    Why do you say “’why are the values of the cosmological constants the values that they are?’ is not a rational question.”?

    It seems like an entirely logical and important question and a worthy scientific pursuit. Perhaps you don’t like the answers, so you try to squelch intellectual curiosity on the subject?

    You explain it this way: “They simply are because they cannot be any other way.”
    How do you know this? If what you say is true, then the leading argument against teleological AP (infinite universes) is of no use. If there is only one way it can be then it will be the same in every universe, and the mathematical problem still stands.
    Say two human siblings were raised by wolves never seeing human life. The sister finds a glove and, seeing it perfectly fits her hand, remarks that it probably was designed for a hand. Her brother scoffs and insists such a thing is not possible.
    See? The puddle analogy works both ways. We actually know how puddles form and it is a simple, matter-based explanation. For your analogy to hold in the case of the anthropic principle, we would need a material reason that the constants are so finely tuned, a hopeless folly.
    That is, unless you are claiming the puddle fits the hole it is in because there are infinite holes and this one just happens to fit the puddle.