I am excited to introduce to you Dr. William Lane Craig. Dr. Craig accepted an invitation to post to Fingerprints of God, and will expose you to some excellent philosophy regarding the argument for the fine tuning of the universe: That the fact that the universe is fine tuned can only be explained by design.
Dr. Craig earned his PhD in philosophy from the University of Birmingham, and his DTheol from the University of Munich, Germany. He is currently research professor of philosophy at Talbot School of Theology in La Mirada, California. He is also the founder of the Reasonable Faith website located at www.reasonablefaith.org. He has written numerous books and articles including Reasonable Faith, Hard Questions Real Answers, Time and Eternity: Exploring God's Relationship to Time, and Two Tasks of the Christian Scholar: Redeeming the Soul, Redeeming the Mind.
It is my pleasure to turn the mic over to my special friend, Dr. William Lane Craig!
CHANCE AND THE ARGUMENT FROM FINE-TUNING
Here’s a very simple argument from fine-tuning for a Cosmic Designer:
1. The fine-tuning of the universe is due to either physical necessity,
chance, or design.
2. It is not due to physical necessity or chance.
3. Therefore, it is due to design.
This is a logically valid argument, whose conclusion follows necessarily from the two premises. So the only question is whether those premises are more plausibly true than false.
The first premise is unobjectionable because it just lists the three alternatives available for explaining the fine-tuning.
As for the second premise, the alternative of physical necessity seems fantastically implausible. It would require us to say that a life-prohibiting universe is a physical impossibility. Few are prepared to swallow that claim. So the debate has focused on the second alternative: could the fine-tuning be due simply to chance? According to this alternative, it’s just an accident that all of nature’s fundamental constants and quantities fell into the life-permitting range. We basically just lucked out!
The fundamental problem here is that the chances of a life-permitting universe’s existing are so remote that this alternative becomes unreasonable.
Sometimes people object that it’s meaningless to speak of the probability of a fine-tuned universe’s existing because there is, after all, only one universe. So you can’t say that 1 out of every 10 universes, for example, is life-permitting.
But the following illustration from the physicist John Barrow clarifies the sense in which a life-permitting universe is improbable. Take a sheet of paper and place upon it a red dot. That dot represents our universe. Now alter slightly one or more of the finely-tuned constants and physical quantities. As a result we have a description of another universe, which we can represent as a new dot in the neighborhood of the first. If that new set of constants and quantities describes a life-permitting universe, make it a red dot; if it describes a universe which is life-prohibiting, make it a blue dot. Now repeat the procedure over and over again until the sheet is filled with dots. What you wind up with is a sea of blue with only a few pin-points of red. That’s the sense in which it is overwhelmingly improbable that the universe should be life-permitting. There are simply vastly more life-prohibiting universes in our local area of possible universes than there are life-permitting universes.
Sometimes people will appeal to the example of a lottery in order to justify the chance alternative. In a lottery where all the tickets are sold, it’s fantastically improbable that any one person should win, yet somebody has to win! It would be unjustified for the winner, whoever he may be, to say, “The odds against my winning were 20 million to one. And yet I won! The lottery must have been rigged!”
In the same way, they say, some universe out of the range of possible universes has to exist. The winner of the universe lottery would also be unjustified to think that because his universe exists, this must have been the result of design, not chance. All the universes are equally improbable, but one of them, by chance, has to win.
This analogy is actually very helpful because it enables us to see clearly where the advocate of chance has misunderstood the fine-tuning argument and to offer a better, more accurate analogy in its place. Contrary to popular impression, the argument from fine-tuning is not trying to explain why this particular universe exists. Rather it’s trying to explain why a life-permitting universe exists. The lottery analogy was misconceived because it focused on why a particular person won.
The correct analogy would be a lottery in which billions and billions and billions of white ping pong balls were mixed together with just one black ping pong ball, and you were told that one ball will be randomly selected out of the horde. If it’s black, you’ll be allowed to live; if it’s white, you’ll be shot.
Now notice that any particular ball which is randomly selected is equally improbable: no matter which ball rolls down the chute, the odds against that particular ball are fantastically improbable. But some ball must roll down the chute. This is the point illustrated by the first lottery analogy. That point, however, is irrelevant because we’re not trying to explain why this particular ball was picked.
The relevant point is that whichever ball rolls down the chute, it is overwhelmingly more probable that it will be white rather than black. Getting the black ball is no more improbable than getting any particular white ball. But it is incomprehensibly more probable that you will get a white ball instead of a black one. So if the black ball rolls down the chute, you certainly should suspect that the lottery was rigged to let you live.
If you still don’t see the point of this analogy, then imagine that in order to be allowed to live, the black ball had to be randomly picked five times in a row. (If the odds against getting a black ball even once are great enough, happening five times rather than once won’t really affect the probabilities significantly.) If such a thing actually happened, everyone would recognize that it did not happen by chance.
So in the correct analogy, we’re not interested in why you got the particular ball you did. Rather we’re puzzled by why, against overwhelming odds, you got a life-permitting ball rather than a life-prohibiting ball. That question is just not addressed by saying, “Well, some ball had to be picked!”
In the same way, some universe has to exist, but whichever universe exists, it is incomprehensibly more probable that it will be life-prohibiting rather than life-permitting. So we still need some explanation why a life-permitting universe exists.
Some people have argued that no explanation is needed for why we observe a life-permitting universe because that’s the only kind of universe we can observe! If the universe were not life-permitting, then we wouldn’t be here to ask about it. (This is the so-called Anthropic Principle, which says that we can observe only properties of the universe which are compatible with our existence.)
This reasoning is fallacious. The fact that we can observe only life-permitting universes does nothing to eliminate the need of an explanation for why a life-permitting universe exists.
Again, an illustration can help. Imagine you’re traveling abroad and arrested on trumped-up drug charges. You’re dragged in front of a firing squad of one hundred trained marksmen standing at point blank range. You hear the command given, “Ready! Aim! Fire!”, and you hear the deafening sound of the guns. And then you observe that you’re still alive! That all of the one hundred marksmen missed! Now what would you conclude?
“Well, I guess I shouldn’t be surprised that they all missed! After all, if they hadn’t all missed, I wouldn’t be here to be surprised about it! Nothing more to be explained here!”
Of course not! It’s true that you shouldn’t be surprised that you don’t observe that you’re dead, since if you were dead; you wouldn’t be able to observe it. But you should still be surprised that you do observe that you are alive, in light of the enormous improbability of the marksmen’s all missing. Indeed, you’d probably conclude that they all missed on purpose, that the whole thing was a set-up, engineered for some purpose by someone.
Theorists have therefore come to recognize that the Anthropic Principle cannot eliminate the need of an explanation of the fine-tuning unless it’s conjoined with a Many Worlds Hypothesis. According to that hypothesis, our universe is but one member of a World Ensemble or “multiverse” of randomly ordered universes, preferably infinite in number. If all of these other universes really exist, then by chance alone life-permitting worlds will appear somewhere in the World Ensemble. Since only finely-tuned universes have observers in them, any observers existing in the World Ensemble will naturally observe their worlds to be finely-tuned. So no appeal to design is necessary to explain fine-tuning. It’s pure chance.
One way to respond to the Many Worlds Hypothesis would be to show that the multiverse itself also involves fine-tuning. For in order to be scientifically credible, some plausible mechanism must be suggested for generating the many worlds. But if the Many Worlds Hypothesis is to be successful in attributing fine-tuning to chance alone, then the mechanism that generates the many worlds had better not be fine-tuned itself! For if it is, then the problem arises all over again.
But the proposed mechanisms for generating a World Ensemble are so vague that it’s far from evident that the physics governing the multiverse will be free of any fine-tuning. For example, if super-string theory, or M-Theory, is the physics of the multiverse, then it remains unexplained why exactly 11 dimensions exist, as the theory requires. And the mechanism that actualizes all the possible universes in the cosmic landscape may involve fine-tuning. So the postulate of a World Ensemble is by itself not enough to justify the alternative of chance.
Moreover, many theorists are sceptical of the Many Worlds Hypothesis itself. Why think that a World Ensemble actually exists? There’s no independent evidence that the sort of World Ensemble required by the Many Worlds Hypothesis actually exists. By contrast, we have good independent reasons for believing in a Designer of the cosmos, in the form of various versions of the cosmological argument.
Finally, the Many Worlds Hypothesis faces what may be a devastating objection. Roger Penrose of Oxford University has pressed this objection forcefully. He points out that the odds of our universe’s initial low entropy condition’s existing by chance alone are one chance out of 1010 (123). By contrast the odds of our solar system’s suddenly forming by the random collision of particles is one chance out of 1010 (60). This number, says Penrose, is “utter chicken feed” in comparison with 1010 (123). What that means is that it is far more likely that we should be observing an orderly universe no larger than our solar system, since a world of that size is so unfathomably more probable than a fine-tuned universe like ours.
In fact, a sort of illusionism results from the Many Worlds Hypothesis. A small world with the illusion of a wider cosmos is more probable than a real, finely-tuned universe. Carried to its logical extreme, this has led to what theorists have called “the invasion of the Boltzmann brains.” For the most probable observable universe is one which consists of a single brain which pops into existence by a random fluctuation with illusory perceptions of the external world! So if you accept the Many Worlds Hypothesis, you’re obligated to believe that you are all that exists and that your body, the earth, and everything you perceive in the world are just illusions.
No sane person believes that he is a Boltzmann brain. On atheism, therefore, it is highly improbable that there exists a randomly ordered World Ensemble. Ironically, the best hope for partisans of the multiverse is to maintain that God created it and ordered its worlds, so that they are not randomly ordered. God could give preference to observable worlds which are cosmically fine-tuned. To be rationally acceptable, the Many Worlds Hypothesis needs God.
With the failure of the Many Worlds Hypothesis, the last ring of defense for the alternative of chance collapses. Neither physical necessity nor chance provides a good explanation of the fine-tuning of the universe.
Thanks Dr. Craig! Keep up the great work! For another excellent talk on the origin of the universe, please click here to see Dr. Craig speak at Saddleback Church in California!
Next week I will talk about the Anthropic Principle and the Anthropic Principle Inequality.
Till then, enjoy.
Tom