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Wednesday, February 17, 2010

Logical Arguments for the Existence of God

There are many arguments for the existence of God that I believe are both valid and sound. However, some I think are more compelling (or should be) than others.

The following are what I believe to be the best logical arguments for the existence of God:

The Transcendental Argument:

1. Laws of logic exist and are binding on human thought.
2. If there is no God, 1 would not hold.
3. 1 does hold.
4. Therefore God exists.

(this is the abbreviated version. For a full version see:

The Ontological Argument (Plantinga’s “victorious” model):

(Your understanding of this model will be greatly influenced depending on your understanding of modal logic.)


Maximal excellence: To have omnipotence, omniscience and moral perfection in some world.

Maximal greatness: To have maximal excellence in every possible world.

1. There is a possible world (W) in which there is a being (X) with maximal greatness.
2. But X is maximally great only if X has maximal excellence in every possible world.
3. Therefore X is maximally great only if X has omnipotence, omniscience and moral perfection in every possible world.
4. In W, the proposition "There is no omnipotent, omniscient, morally perfect being" would be impossible—that is, necessarily false.
5. But what is impossible does not vary from world to world.
6. Therefore, the proposition, "There is no omnipotent, omniscient, morally perfect being" is necessarily false in this actual world, too.
7. Therefore, there actually exists in this world, and must exist in every possible world, an omnipotent, omniscient, morally perfect being.

The Moral Argument:

1. Real moral obligation is a fact. We are really, truly, objectively obligated to do good and avoid evil.
2. Either the atheistic view of reality is correct or the "religious" one.
3. But the atheistic one is incompatible with there being moral obligation.
4. Therefore the "religious" view of reality is correct.

The Argument from Conscience:

This is actually not a formulated argument, but a follow up to the moral argument if someone objects to real or objective morality. We can then point out that they will all, no matter their convictions, universally accept that we should obey our conscience. Besides the fact that this actually functions as a universal, objective, obligation (“we OUGHT to obey our conscience”) we can still ask where did conscience get such an absolute authority—an authority admitted even by the moral subjectivist and relativist? There are only four possibilities.

1. From something less than me (nature)
2. From me (individual)
3. From others equal to me (society)
4. From something above me (God)

Let's consider each of these possibilities in order.

1. How can I be absolutely obligated by something less than me—for example, by animal instinct or practical need for material survival?
2. How can I obligate myself absolutely? Am I absolute? Do I have the right to demand absolute obedience from anyone, even myself? And if I am the one who locked myself in this prison of obligation, I can also let myself out, thus destroying the absoluteness of the obligation which we admitted as our premise.
3. How can society obligate me? What right do my equals have to impose their values on me? Does quantity make quality? Do a million human beings make a relative into an absolute? Is "society" God?
4. The only source of absolute moral obligation left is something superior to me. This binds my will, morally, with rightful demands for complete obedience.

Thus God, or something like God, is the only adequate source and ground for the absolute moral obligation we all feel to obey our conscience. Conscience is thus explainable only as the voice of God in the soul.

The Argument from Desire:

1. Every natural, innate desire in us corresponds to some real object that can satisfy that desire.
2. But there exists in us a desire which nothing in time, nothing on earth, no creature can satisfy.
3. Therefore there must exist something more than time, earth and creatures, which can satisfy this desire.
4. This something is what people call "God" and "life with God forever."


  1. Well, avoiding that version of TAG, since I haven't had time to examine it, the rest of those arguments are easily dismissed.

    Ontological argument
    Anslem's original ontological argument and all thereafter until Plantinga were easily dismissed by Kant's explanation that existence was not able to be a property. Plantinga's argument isn't really championed by him at all. He knows very well that his argument can be dismissed merely because you can also use the same argument to prove that a maximally great being does not exist.

    William Lane Craig admits that the argument in reverse is logically valid, and the real reason to accept the ontological argument is not that it is logical proof, but because it sounds better than a maximally great being not existing.

    Further, in modal logic, saying "It is possible for a maximally great being to exist" is the same exact thing as saying "A maximally great being exists" and therefore the premise presumes the outcome, which is begging the question.

    Argument from Moral Authority
    This argument doesn't have to be dealt with at premise two, it can be dismissed at premise three.

    The reason religion thinks it can answer the question is because it asserts God's commands are moral. If you ask why God's commands are moral, you have to say that it is either that God commands things because they are moral, or things are moral because God commands them. This is the typical Euthyphro dilemma.

    While I have just touched on it here, I have dealt with objections to the Euthyphro dilemma on multiple occasions on my blog, most recently at William Lane Craig's Paradigm Paradox, where I show the only argument I've found against the dilemma to be entirely circular.

    Also, if it is the ultimate judge idea, you would have to admit that the only reason to be moral is due to fear of punishment or desire for reward. This would mean that people are not actually moral, but are merely being selfish. It would also not explain how people that don't believe in God can still act moral since they would not have such a fear of punishment, or an expectation of reward.

    The Argument from Desire
    How about the fact that I have no such desire. I would also suggest that the desire for God stems from fear, and therefore would be more likely coined "The Argument from Fear".

  2. Ahh, Matt Slick's TAG. He and I have actually had a back and forth a bit with that argument. The argument is a huge failure though. I have refuted his argument, then I refuted his refutation of my argument. You can see it at Matt Slick Attempts to Answer my Refutation of TAG.

    That is the final post on the subject, but there are links to the earlier posts on the subject.

  3. I read your refutation of Slick's TAG. To be brief, I think you fundamentally misunderstand the argument, and fundamentally misunderstand then nature of logic itself. You redefine logic as "truth statements". This is actually trying to defeat the argument my changing it. Laws of logic are not the statements, they are the governing principles that truth statements must abide to be true. What you are actually talking about are premises of a logical argument. It is very different than logic itself.

    Laws of logic are things like the law of excluded middle or the law of non-contradiction. The law of non-contradiction is not itself a "truth claim" but rather a governing principle that a true premise must not violate - it cannot be A and not-A in the same time/way/place.

    So youre refutation of Slick's TAG seems just, well not to be rude, but really ignorant of both the argument and what logic is.

    As for your other statements:

    About the ontological argument. I didn’t argue Anselm’s (though I actually think it is sound, it seems so abstract that it is impossible for it to be compelling). Plantinga actually DOES champion his own model – it is found in his book God, Freedom and Evil. He calls it the “Argument Triumphant” in that it triumphs over all the objections that are launched against ontological arguments. He even says that the argument is sound. His only contest against it is that it is still not compelling – even though there seems to be no flaw in the argument.

    Now, as for the supposed attempt to use an ontological argument to prove that a maximally great being doesn’t exist. The problem with that kind of argument is twofold – the first is one of definition, the other is of logic. First, but definition, a maximally great being MUST exist. In order for the negation argument to work, the being must actually be something LESS than a maximally great being. It is basically like trying to show that a necessarily existent being does not exist necessarily. It argues for a contradiction. A non-existent being CANNOT be maximally great and so in order to show that a maximally great being doesn’t exist, you must first assume that the being is not maximally great to begin with.

    Logically it has the problem of trying to prove a universal negation. This, it seems in logic, is never possible. You can only prove a universal negative if that universal negative is a logical impossibility such as a square-circle or a non-sense concept like a glumph-glomph-gloamph. But in that case you must first prove that the concept of a maximally great God is either a logical impossibility or a non-sense concept.

    Plus your circular argument also misunderstand the nature of both the argument and of modal logic. Based on modal logic all one must show is that something is logically possible in one world – and so long as it is not ILLOGICAL it obtains. Thus Plantinga is not assuming his conclusion by assuming that it is logically possible for a maximally great being to exist in one world. There is not illogical about it. He then argues from there to show that if it is logically possible that a maximally great being exists in one world, that NECESSITATES that such a being exists with maximal excellence in ALL worlds. It is only circular with the conclusion is contained in a premise. In this case the conclusion is ENTAILED by a premise (which is the entire point of a logical argument: to show that a conclusion is entailed by its premises) but it is not assumed.

  4. There is however a way to disprove the argument, but in doing so you must try to prove modal logic itself to be false (a daunting task). But you could argue from a premise that there is a possible world in which there are no other possible worlds, to the conclusion that there are no other possible worlds. But in arguing this way to deny the ontological argument, you also deny modal logic (even though you used modal logic to do so). Its complicated and I’m not sure its possible.

    As for your treatment of the moral argument. You not only misunderstand the Theistic argument for the basis of morality, but also overestimate the Euthyphro dilemma. Euthyphro is only a viable critique IF the two options it provide are the ONLY two options. All the theist must do is show that there are POSSIBLE alternative (they don’t even have to prove them, just show there are other possible answers) and thus Euthyphro is simply invalid as a false dilemma. The problem is that in your conception of the theistic argument, and in the Euthyphro dilemma, is the morality is based on the COMMANDS of God – or on God’s decrees and thus are either capricious or submissive to another standard. Well to a degree the commands ARE submissive to another standard – the immutable NATURE of God. If the moral commands of God are actually based on God’s immutable nature than God is neither capricious or submissive to a higher authority.

    You also point to the circularity of the argument – missing that any appeal to an ultimate authority will be NECESSARILY (though not VICIOUSLY) circular. Why? Because it IS the absolute authority. There can be nothing higher to appeal to! This is true no matter what your authority base is.

    If your absolute authority of what is true is based on reason, you will always end up defending reason because it is reasonable. If you assume it is true because it is empirically verifiable, then you must always at some point hit a wall where it is true because it is itself empirically verifiable. Etc. When we are talking about basis of authority, ALL absolute authorities will be necessarily circular. This will happen whether your absolute authority is God, self, society, reason, science, empirical evidence, etc. It will always end up pointing to itself.

  5. And God being the ultimate judge does not mean that what makes us moral is fear of punishment or desire for reward. Does a child obey their parents SOLELY because they fear punishment or desire reward? Do we not obey because of who they are and who we are? Or because we love them? Do we obey the state in all cases simply because we fear punishment? Do we not obey the laws because in some cases we just believe it to be right? Am I faithful to my wife because I am afraid of punishment? Or do I do it just because I love my wife?

    In fact that kind of argument really just seems so blindly naïve or else purposefully misleading and disingenuous.

    Finally your argument against the argument from desire also shows that your don’t understand the argument, yourself, humanity, or all three. I recommend listening to Kreeft’s formulation on this argument.

  6. Oh, and for further treatment on the moral argument and euthyprho, look at the next post.