Real Theistic Design Arguments Aren’t Circular

I had a fascinating discussion with someone recently who posed an interesting argument. He said that theists who point to the incredible unlikelihood of the appearance of life, and so conclude that God designed the universe, are actually proposing circular fallacious arguments. He said it like this:


“by using high improbabilities in an argument for ID [design] you inadvertently presuppose that humanity was the purpose of the universe. Obviously, presupposing that humanity is the purpose of the universe [also] presupposes a purpose owner. So, using high improbabilities in an argument for ID makes the ID argument circular in that it presupposes its own conclusion.”[1]


In other words, he is claiming that Theists argue for design like this:

1 – Nature looks designed.

2 – If nature is designed, there was a purpose behind that design.

3 – A purpose is owned by an agent.

4 – Only God is a powerful enough agent to design the universe.

5 – Therefore God designed the universe.


Unfortunately, this argument is fallacious. It is an incoherent argument. Why? It begs the question. How? Because God appears as a premise in the argument (4) and also a conclusion to the argument (5). The argument therefore assumes what it proports to prove. That’s a pointless exercise, right there! It’s a bad argument for God.


I must say I agree with my friend here. And if scholarly theists were putting forward this argument in the fields of either Intelligent Design, or the fine tuning of the universe, then they would be rightfully shut down. This argument does not prove that God exists at all.


My friend’s problem is – that scholarly theists DON’T use this argument. Why? I guess for many reasons. But possibly because they see no need to make the logical leap he decides to make in premise (2).


Fine-Tuning of the Universe

Our discussion started around the fine-tuning of the universe. This is the scientific observation that the range of life permitting values for the constants and quantities in our universe is incredibly narrow. If they were altered by the narrowest of margins, life could not exist because the universe would be life-prohibiting. We simply have to accept these incredibly specific and arbitrary values. It is how nature works. If they were set to any other value, life would not exist.


While theists point out the mathematical probabilities regarding the universe, they do not directly infer some divine purpose as a result. Rather, they simply say – the universe is mathematically precise. But they don’t immediately presuppose therefore that it was designed. Rather, they consider the possible explanations for that precise state of affairs.


6 – Nature looks fine-tuned.

7 – The fine-tuning of the universe is either due to physical necessity, chance or design.

8 – It is not due to either physical necessity or chance.

9 – Therefore it is due to design.


The conclusion of design is an inference to the best explanation, because neither chance or necessity work as explanations. Having inferred the “design” explanation, they then go on to explore the options for the Designer. And this leads the Theist eventually to conclude that God would have the power, wisdom and immaterial nature to be this Designer.

Mathematical improbabilities are therefore used to build the theistic case, but do not suppose any conclusion.

But, you might be asking – hang on. Why does premise (8) say physical necessity or chance aren’t good candidates for explaining cosmic fine-tuning?


Why Does Physical Necessity Not Work?

Perhaps this is the only way the universe could be? But the problem is that the constants and values are not determined by nature. Rather, they form nature as we know it. So why would these values be necessary then? Couldn’t they be set to a different value? Of course if they were, then life would not be possible in the universe.

To say that the universe HAS to look this way is also saying that a life-prohibiting universe is impossible. Those are pretty big claims. And there seems to be no way to justify these claims beyond shrugging and saying, “I like it better this way.”

Yet when we look at the probabilities involved, it suggests that a non-life permitting universe is MUCH MORE LIKELY than a life permitting one. So non-life permitting universes are likely, and so the physical necessity explanation breaks down.


Why Does Chance Not Work?

Often the non-theist will say, it’s just by chance that we are here. Hey – someone has to win the lottery. Right? It’s unlikely you’ll win, but someone has to and this happens every week…it’s a mundane occurrence (tho not for the winner!). Given this analogy, it is wrong to think of a universe designer, because that would effectively be tantamount to rigging the lottery.

Craig observes at this point that the skeptic has misunderstood the argument for design. In its place, he suggests this analogy.[2]

Imagine a lottery where billions and billions of white balls are mixed together with a single black ball. And on the night of the draw, a single ball is withdrawn from the ball container. If it’s the black ball, you get to live. If it’s a white ball, then you are shot dead.

Notice that when any particular ball is drawn, the result is improbable. The odds against a particular ball are astronomical. BUT – that fact is IRRELEVANT. We are not trying to explain why a particular ball was picked. Getting a white ball is no more probable than getting the single black ball. But its MORE probable you will get the white ball.

The point is – if the black ball is drawn from the lottery, and it happens that way five weeks in a row, then you would be within your rights to assume that this lottery had been rigged. And this is what the fine-tuning argument is doing. It’s not trying to explain why THIS universe exists. Rather, it’s trying to explain why a LIFE PERMITTING universe exists.

Notice, it’s not actually about the odds at all. Rather, it’s about WHY the black ball comes out 5 times in a row. Just saying, “some ball had to be picked” is not the issue. So – the chance conclusion does not work, and does not do a solid job of explaining the fine-tuning of the universe.


Summary of the Cosmic Fine-Tuning Argument

What if we rearranged my friend’s argument to be something closer to what theists say? It would be this:

10 – Nature is fine-tuned.

11 – The fine-tuning of nature is either the result of natural necessity, chance or design.

12 – Fine-tuning is not the result of natural necessity or chance.

13 – Fine-tuning is the result of design.

14 – God owns the attributes to be identified as the designer.


[1] @stuhgray, twitter conversation, 07/12/19 – 08/12/19.

[2] William Lane Craig, On Guard Defending Your Faith with Reason and Precision, (Colorado Springs:David C. Cook, 2010), Loc 1856 – 1878, summarized.


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I live in the UK, I'm married to Janet and I'm passionate about proposing a case for the historic Christian faith. You can find me on Twitter at @stuhgray.

13 thoughts on “Real Theistic Design Arguments Aren’t Circular”

  1. 10 – Nature looks fine-tuned.

    11 – The fine-tuning of nature is either the result of natural necessity, chance or design.

    12 – Fine-tuning is not the result of natural necessity or chance.

    13 – Fine-tuning is the result of design.

    14 – God owns the attributes to be identified as the designer.

    So you start with an assumption in #1 and you cannot show that this is the case. “Nature doesn’t look fine tuned”, is all anyone needs to throw this idea out. 99.9999…% of the universe is inimical to human beings. It’s more fined tuned for bacteria than humans.

    There is no simple chance in the universe, it all operates on the laws of physics. This is not a Dr. Seussian universe where literally anything can happen.

    1. What’s more – you also seem to concede that nature is fine tuned for life of some kind, and that the laws of physics operate precisely. Well – you are simply making my point there.

  2. In your section on physical necessity, you rightly point out that we have no good reason to think that the values possessed by natural constants are due to physical necessity. However, that does not imply that they therefore AREN’T due to physical neccessary. Science has not ruled out physical necessity. There’s simply not enough data to conclude reasonably in either direction.

    In your section on chance, even if you are correct to claim that the values of the universal constants are highly improbable to have been settled completely at random, you have not shown that an intelligent designer is more probable. You haven’t even shown that the probability of an intelligent designer is non-zero. In order for an intelligent designer to be a more reasonable explanation than purely random chance you have to show that intelligent design is both possible and more probable than purely random chance.

    1. It’s not clear to me that appealing to ignorance counters the philosophical arguments against natural necessity. And it seems reasonable to favour the design argument as a matter of course if natural necessity and chance seem to fail. Unless there’s a fourth option, of course.

      1. You misunderstand. I’m saying that the only thing which you’ve offered as an argument against natural necessity is an appeal to ignorance. You’re saying that we have no good reason to think that the values of the constants ARE due to physical necessity, but you offer no other reason to think that they are NOT.

        Similarly, chance only fails if you can show that your alternative is both possible and more probable than pure randomness, regardless of how improbable pure randomness may be. You have not shown that intelligent design is possible and you certainly haven’t established that it has a greater probability than pure randomness.

      2. What I’ve done on the natural necessity option is pose a question. How can you justify the claim that a life prohibiting universe is impossible? That’s actually an open question. So – I’m not closed to getting an answer to it.

        Again – on chance – I think you can demonstrate that randomness is an unreasonable conclusion to draw. But sure – you CAN still say – there’s always a chance… Seems unreasonable to me personally to stop there.

        I’m trying to show design is a more reasonable conclusion to draw – in the absence of answers to natural necessity – in the face of fine tuning and our knowledge about the cosmological constants. As various atheist scientists have said…the Universe sure looks designed…

      3. You haven’t simply posed a question, regarding physical necessity. The Fine Tuning Argument, as you’ve presented it, posits an answer to the question as one of its premises. I’m saying that it is no more justifiable to claim that physical necessity is impossible than to claim that it is possible.

        Regarding chance, how can you demonstrate that it is less reasonable than some other option without first showing that other option is both possible and more probable than chance?

        As regards those people, theist or atheist, who have claimed that the universe looks designed, I am happy to disagree with them.

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