This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.

Dr. William Lane CraigVery rarely do I engage in online conversations with someone, but when a Facebook follower named Bob voiced an objection to the kalām cosmological argument (KCA), my curiosity was piqued by his cryptic remark. So I asked him to explain himself, and thus began a dialogue on the merits of his objection. I sincerely wanted to help Bob see his missteps and state his objection more carefully. To no avail, it seems! I think Bob’s objection is a mare’s nest of confusions; he thinks I need some lessons in logic! With his permission, I’m posting our dialogue so that you can decide for yourselves.
I think that our exchange can be useful in a number of ways. It illustrates well the value of Greg Koukl’s two questions: “What do you mean by that?” and “How did you come to that conclusion?” What you’ll often discover is that the other person is using words in idiosyncratic ways and that his reasons for believing as he does are confused. I also think that our dialogue is pedagogically useful. Ask yourself with each reply, “How would I respond to that?” Such an exercise should help to develop your dialectical skills. Finally, I hope that our dialogue can serve as an example of civility in a day in which people of opposing views can be very uncivil toward one another. The critique can be straightforward and hard-hitting, but polite. I hope you enjoy our exchange!
-Dr. William Lane Craig

The Dialogue


The KCA is taxicabbing because it implies the universe does not exist then halts this line of reasoning when it comes to the one principle the theist needs for their argument


Wait! Explain this. What does 'taxicabbing' mean? Is this related to Pruss' taxicab fallacy?


It means to ditch your own logic when it no longer suits you.

"The universe doesn't exist...except for this one principle I need to make this argument for this being I just happen to have a massive emotional attachment to"

It's a specialized form of confirmation bias


OK, so this is in fact a version of Pruss' humorously named fallacy. As such it should be clear that the proponent of the KCA can't be accused of such a fallacy, for he never gives up or makes exception to the principle 'whatever begins to exist has a cause.' If anyone is guilty of this fallacy, it's the atheist who accepts this principle in every other case but then arbitrarily exempts the universe.

As for your claim above, it's hard to make any sense of it. The proponent of the KCA does not affirm that 'the universe doesn't exist.' He affirms that 'the universe began to exist.' And what is the one principle he needs? Just the enunciated causal principle, which he holds to w/o exception. Of course, if God began to exist, He would need a cause. Things that are eternal don't begin to exist and so don't need causes.


Except that the theist goes on to say the universe began to exist. That would be causality also did not exist prior to that. The atheist is guilty of no such thing because we're not claiming that causality applies to anything other than pre-existing matter and energy.

If the theist is to escape this logical fallacy, they must give a demonstrable example of causality not within the universe. Otherwise they're unable to justify their exemption of causality over, say, conservation of energy. If the universe began to exist, the principles within that universe began to exist.


It begs the question to say causality did not exist prior to the beginning of the universe. Maybe you're under the false impression that the proponent of the KCA says nothing existed prior to the universe. But he doesn't say that. On the contrary his consistent assumption of the causal principle requires that causally prior to the universe is a being which did not begin to exist and is uncaused. There's just no fallacy here.

It's a false inference that principles which hold within the universe hold ONLY within the universe. Consider logical principles, for example. In the same way the causal principle is a metaphysical principle whose applicability is not restricted to within the universe. You mistakenly take the causal principle to be a physical principle like the law of gravity or the laws of thernodynamics, which apply only within the universe. By contrast the causal principle is not a law of nature but a first principle of metaphysics. It is metaphysically absurd that the universe should pop into being from non-being.


No it doesn't. That's following the logic of the universe not existing and remaining consistent. That's where the theists taxicabbing comes in. "By contrast the causal principle is not a law of nature but a first principle of metaphysics." Evidence of a causation event not within the universe? In this context, saying "It's metaphysical" is no different than saying "It's magic" in an effort to salvage the argument.


"That's following the logic of the universe not existing and remaining consistent." This sentence is unintelligible. What does it mean? There is no taxi cab fallacy because no exception is made to the causal principle.

Metaphysics is hardly magic. What's worse than magic is believing the universe came into being without a cause. A consistent application of the causal principle leads you beyond the universe. To deny this, you need to give some reason to restrict the principle to something like a law of nature, which it's clearly not.

It's obvious to me as a result of our conversation that you are not really alleging a fallacy against the argument. Rather you just deny the first premiss. You would be clearer in your objection if you just say plainly that you reject the first premiss, rather than muddy the waters with accusations of fallacy, There is no fallacy, just a disagreement about the truth of the first premiss.

The issue, then, is whether we have better reasons for thinking the first premiss true than false. I consider my reasons much better than yours, since you haven't been able to justify the claim that causality holds only within the universe (think again about the analogy to the laws of logic).


The exception is made when it comes to the causal principle. You're trying to say that universe did not exist, except for the one principle you need to make your argument work. That's the epitome of taxicabbing.

I didn't say metaphysics was necessarily magic. I said in this instance it's no different than invoking magic.

No, saying the universe didn't require a cause is actually being consistent because the principle by which a cause precedes an effect exists within the universe.

Leads you beyond the universe? Do you have an observed example of a cause and effect not within the universe?


I'm saying the universe began to exist, and the causal principle REQUIRES there to be something causally responsible for its coming to be. There's no 'taxicab fallacy' because no exception is made to the causal principle. It's not a matter of 'making the argument work'; it's a matter of what is implied if the two premisses are true.

"the principle by which a cause precedes an effect exists within the universe." Ah, but what you have to show is that the principle holds ONLY within the universe. You haven't shown that. Think again about the laws of logic, which also hold within the universe but aren't limited to within the universe.

"Do you have an observed example of a cause and effect not within the universe?" Of course not, since I cannot observe something beyond the universe. But the truth of the two premisses implies the existence of such a cause. Think of the analogy of the multiverse. We can't observe the multiverse because we are contained in ours; but we could have good reasons for positing such a thing. No cosmologist would rule out a multiverse simply because such a thing can't be observed.

It has become clear to me that your rejection of the argument is really based, not on any supposed fallacy, but on your denial of the causal principle as expressed in the first premiss. You believe that the causal principle is restricted to within the universe. But you have no reason for so restricting it, any more than for restricting the laws of logic.


But if the universe began to exist then the principle of causality also began to exist. You can't have it both ways, that's the fallacy I was referring to

"The universe didn't exist, except for, no apparent reason, this one principle I need to make my argument work"



"if the universe began to exist then the principle of causality also began to exist." Bob, this is just confused. The principle of causality isn't a thing. A principle is either true or false; it's not something that either exists or not. You're confusing a truth with a thing. If the principle is, indeed, a thing, then it would at most be something like a proposition. But propositions don't begin to exist. They are abstract objects which exist permanently (if they exist at all!). So you shouldn't think that if the universe began to exist, so did the principle of causality.

The remainder of your message looks as if it's supposed to be a quotation from me but is just garbled.


An abstract object is defined as a concept or an idea. Both concepts and ideas exist within the universe. You have to show an example of anything at all pertaining to your argument which exists outside of the universe to even hope to salvage your argument.

My quotation was a summation of why your argument is fallacious. You're trying to excuse the one principle you need from non-existence and ignore your own logic of the universe beginning to exist. That's special pleading and confirmation bias.


You don't understand what you're talking about. Nobody defines abstract objects as concepts or ideas immanent in the universe. I know the literature on this; I've been studying it for over a dozen years. Abstract objects (if they exist at all) include things like mathematical objects like numbers, sets, and shapes, properties, propositions, possible worlds, and so on. If there are such things (of which I'm dubious), they don't begin to exist but transcend space and time. So the existence of such things is no exception to the causal principle. If the causal principle is any kind of a thing at all (of which I'm dubious), it's a proposition. So it doesn't begin to exist, as does the universe.

Do you think the causal principle even is a thing? I don't. Whatever-begins-to-exist-has-a-cause is not a thing. But if it is, it's not a thing which begins to exist.

So your objection is really hopeless. It depends on the assumption that the causal principle is a thing which begins to exist. Good luck trying to prove that!


An abstract object is an object which does not exist at any particular time or place, but rather exists as a type of thing, i.e., an idea, or abstraction.

Try again

Causality is a principle, one which exists within the universe. That's how principles work. They're properties of matter and energy. For instance, if there is no energy then there would be no conservation of energy.


So Wikipedia is your source of knowledge on abstract objects, is it? You don't even understand the article. The author is using 'idea' in a very abstract sense, not as a thought. This is evident by his saying they don't exist in time and space, as you claimed. Your own source and citation refutes you.

You don't understand the terms you use. Principles are true or false; material things are not.

I think after our dialogue that it's obvious that you've failed to identify any fallacy in the KCA. Rather you simply reject the truth of the first premiss. But you have no good reason for doing so, since the holding of a principle within the universe gives no warrant for saying that it holds only within the universe (cf. the laws of logic).

In fact, Your objection is so confused that I've decided to add it to my list of "Objections so Bad I Couldn't Have Made Them Up: The World's Ten Worst Objections to the KCA." You have managed to supplant one of the previous top ten!


Wikipedia is recognized as being as reliable as EB. Saying he's using the concept of 'idea' in the abstract sense is completely circular reasoning. Abstract simply means something not physical or concrete. That does not mean it is not dependent on the physical. A thought is abstract. Do you have an example of a thought that is not dependent on a mind?

Funny how you call me objection bad and confused while simultaneously being entirely unable to address any of it.

I've elaborated the fallacy in the KCA so simply a four year old could understand it

You abandon your own logic of the universe not existing when you get to the one principle you need to make your argument work. That's special pleading/taxicabbing


As a result of our dialogue, I’ve finally come to understand your final paragraph, which is so opaque that probably no one but you understands it. Having come to understand your objection, I now see that it is a tissue of errors. Let’s review your mistakes:

1. You falsely accuse the argument of committing the so-called “taxi cab fallacy,” which involves making an arbitrary exception to one’s accepted explanatory principle. The KCA obviously does not do that, since no exception is made to the principle that whatever begins to exist has a cause.

2. In a delicious irony, it actually turns out to be you who can be plausibly accused of committing the “taxi cab fallacy”! For you accept the causal principle within the universe, but arbitrarily exempt the universe from that principle.

3. Your attempt to justify exempting the universe from the causal principle is a patent failure: you fallaciously infer that because the principle holds within the universe, therefore it holds ONLY within the universe. The laws of logic are an obvious counter-example, holding within the universe but not only within the universe.

4. You reify the first premise of the KCA into a thing, to which the causal principle may then be applied. This commits what some philosophers have called the fallacy of misplaced concreteness. The truth “whatever begins to exist has a cause” is not a thing.

5. If the causal principle is any kind of thing, it would be a proposition. But a proposition is an abstract object which does not begin to exist and so is no exception to the causal principle. You don’t understand the nature of abstract objects. Even your own source states that they don’t exist in time and space.

6. You conflate ideas in the sense of non-spatio-temporal abstract objects with ideas in the sense of thoughts, which are spatio-temporal. Thoughts depend on minds; propositions do not.

In sum, it is only your pride that could make you think I haven’t addressed your objection. You need to swallow your pride and try to learn something from our dialogue. You don’t know as much as you think you do.


If you understood it then you would understand that your #1 was utterly wrong. Your logic is "The universe didn't exist, except causality" with zero justification for the exception for causality and zero demonstration that it could have survived outside of the universe

2: That's projection. You're the one arguing that the universe didn't exist. If you're applying extant principles within the universe to before its existence then you don't get to just apply the one you want. You also have to apply things like the conservation of energy which say that energy remains constant in a system. So that means the universe couldn't have been created

3: When you call my attempt a patent failure, you have to remember that you're the one who has no idea how logic actually works. Again, you're the one claiming the universe in which it works did not exist at some point in the past. Do you have a direct observed example of logic applying not within the universe?

4: I never once said or implied it was a 'thing'. I was merely following it to its logical conclusion. If the universe doesn't exist, the principles within don't exist. If you apply any of them, you have to apply all of them. If you do that, conservation beats causality

5: An abstract object is an idea or a concept. Ideas and concepts begin to exist as properties of the mind and therefore properties of matter. Do you have an example of the number 12 outside of the universe?

6: Do you have an example of an abstract concept existing as *not* the property of mind?

In sum, you really haven't addressed any of my objection. You keep rationalizing, ignoring and posting walls of trash hoping I'll get bored and stop refuting you.

Instead of trying to shift the burden, try realizing that you're the one arguing the universe didn't exist then justify causality existing prior to the universe.


I don't see any profit in continuing our dialogue further. I understand your objection and have identified its many mistakes. I'm happy to give you the last word. I'd ask only your permission to post our dialogue, unedited, so that others can read it. I think that it will be an educational experience.


If you understood my objection then you would understand that you haven't addressed any of it.

Sure go ahead, it certainly will be to the logically initiated.

As long as it's in a format in which I can post and correct mistakes such as yours


Thank you!

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