Why should one make an argument for the existence of God? Why, moreover, provide fifteen of them? Is it that the evidence for God is so weak, that believers need multiple arguments, working together in their persuasive power, to change the minds of unbelievers? Questions of whether or not these arguments are useful, or if they can actually coerce religious belief has been an area of interesting debate between philosophers for sometime now.
In philosopher Alvin Plantinga’s essay “Two Dozen (or so) Theistic Arguments” (1986), he firsts asks this question: “What are these arguments like, and what role do they play?”  Plantinga answers this question by saying that these arguments are probabilistic either with respect to (1) the premises, (2) the connection of the premises with the conclusion, or (3) both. Furthermore, “[t]hey can serve to bolster and confirm. . . perhaps to convince” . Of course, Plantinga is careful with what it means for these arguments to be coercive. As he writes, “These arguments are not coercive in the sense that every person is obliged to accept their premises on the pain of irrationality. Maybe just that some or many sensible people do accept their premises (oneself)” . And so, the discussion could go on.
However, I present 15 arguments for the existence of God so that I might establish a strong cumulative case for his existence. This is because some arguments are more so about strong probability (i.e.,the argument religious experience, argument from miracles, etc.) while others can have a demonstrative element to them (i.e., Aquinas’ Third Way). The combination of these given characteristics can (in my opinion) be very effective in a case for theism – particularly, that of Christian theism. These arguments are as follows:
- (I) The Kalam Cosmological Argument
This argument draws from several lines of evidences (mathematics, science, philosophy) that try to connect the premises with its conclusion – namely, that the universe has a cause of its existence. The argument can be summarized as such: The universe cannot have existed forever in the past. In other words, the universe cannot be past-eternal. Why not? We have reached the present moment. If the universe were past-eternal, we would never reach “the present moment”; an infinite amount of “moments” would have to be realized before we reached the “present moment” (which is absurd). Therefore, the universe must be finite. If the universe is finite (i.e., began to exist), then the universe requires a cause (totally separate from it) to bring it into existence.
This cause must transcend space and time – because it created space and time – and therefore must be timeless and immaterial. But, we ask, what sorts of things that are immaterial and timeless, cause things to exist? We only have two options: (1) Abstract objects or (2) a transcendent Mind. By (1) I simply mean something like a number, but of course abstract objects can’t cause anything to exist (the number 7 has no causal power). Therefore, this cause must be a Mind – which is what believers understand to be God.
- (II) Leibnizian Cosmological Argument
Whatever exists has an explanation of its existence. In other words, nothing exists without a reason accounting for that things existence. However, there are two kinds of existence that we have to be clear about: (1) necessary existence and (2) contingent existence. If something necessarily exists, then the explanation of its existence is within itself, not outside of itself.
Philosophers have argued that numbers, properties, and even the laws of logic are all necessarily existent – in the sense that none of these came into existence by some other thing, but rather that they exist by the necessity of their own nature. However, if something is contingently existent, then the reason for its existence is external to it – you and me are contingent, and so is the computer that you are using. The shortcut understanding is this: contingent things have the possibility of existing or not existing, necessary things either must or must not exist. With that understood, the argument is as follows:
- Everything that exists has an explanation of its existence.
- If the universe has an explanation of its existence, that explanation is God.
- The universe exists.
- Therefore, the universe has an explanation of its existence.
- Therefore, the explanation of the existence of the universe is God.
Given our terms above, let us restate (1): “Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.” Why doesn’t God have an explanation of his existence, if he exists? or, who created God? God is a necessarily existent being; he requires no external cause to bring about His existence. God just is – and he cannot not be.
- (III) The Ontological Argument
This is an argument drawing from our idea of God. First, suppose that we were to define God as “the greatest conceivable being” (GCB). Now, let’s assume that GCB only exists in your mind but not in reality. However, isn’t it true that existence in reality is greater than existence in just your mind? A mere idea of 100$ in your pocket is far more lacking in being than a real 100$ in your pocket. Thus, we have the assumption: GCB only exists in your mind. But, existence in reality is greater than existence in the mind. Therefore, GCB must exist in reality as well as in your mind (or else it wouldn’t be the greatest conceivable being). Therefore, the very idea of God suggests that he exists.
- (IV) The Argument from the Origin of the Idea of God
This argument has a close friendship with the ontological argument discussed above. Rather than suggesting that real being is associated with the content of the idea of God, another philosopher (René Descartes) is saying that God is such an idea that he must be the cause or the origin of this idea. The argument runs something like this: (1) We have ideas of many things; we have ideas of things that are real (the earth, the sky, etc.), but we also have ideas of things that appear to be innate. As Descartes writes, “Among these ideas, some appear to me to be innate, some adventitious, and some produced by me. For I understand what a thing is, what truth is, what thought is, and I appear to have derived this exclusively from my very own nature” .
Descartes thence goes on to have a very tedious discussion about these ideas, but what is important to notice is the next step to his argument: “All that remains for me to ask is how I received this idea of God. For I did not draw it from the senses; it never came upon me unexpectedly, as is usually the case with ideas of sensible things when these things present themselves. . . to the external organs” . Descartes contends that God is the source of the idea he has of God. To finish: “[T]he mere fact that God created me makes it highly plausible that I have somehow been made in his image and likeness, and that I perceive his likeness, in which the idea of God is contained, by means of the same faculty by which I perceive myself” .
- (V) The Argument from Design
We notice that certain things according to our experience have been designed – or, displays a mark of intelligibility. For instance, the house requires a builder, the watch requires a watchmaker, and so on. However, what about the universe? We notice that houses and even watches have properties such as “the adjustment of parts into a whole” and “curious adapting of means to ends.” It is the case that the universe has these properties as well. If the universe does have these properties, then we can say that it is probable that the universe was produced by design. We can put the argument like this:
- The universe displays design within the created order.
- Either this intelligible order is the product of chance or of intelligent design.
- Not chance.
- Therefore, the universe is the product of intelligent design.
- Design only comes from a mind, a designer.
- Therefore, the universe is the product of an intelligent designer.
(VI) The Moral Argument
There are various types of moral arguments, but one notable form is a sort of argument regarding “objective moral facts.” The argument runs something like this: For every moral action, there must be a general, overall reason that motivates the given action. In other words, there are instrumental reasons (i.e., “I will this because…”) that we give in order to carry out to an overall good – or, a basic or irreducible good. The foundations of the moral life (as Aquinas called them) are things such as life, beauty, friendship, honesty, justice, truth, and so on and so on. How do we account for these things, and why are we accountable to uphold them? There are various questions that we can ask with respect to responsibility, moral obligation, ability, and so forth. But for now, suppose the following:
- (1) If morality is objective and absolute, then God exists.
- (2) Morality is objective and absolute.
- (3) Therefore, God exists.
This argument is saying that the objectivity of the moral law presumes that God exists. In other words, given that certain things are objectively wrong (murder, etc.), or that they can be held to an objective/absolute standard of right and wrong, they presuppose the existence of God – i.e., an authority by which these moral precepts can be established.
(VII) The Argument from Miracles
Contrary to David Hume’s definition (“a violation of a law of nature”) we can better define miracles as “a specific event that would not have happened if only the natural order had been operating” . Thus, our argument may runs as follows:
- (1) A miracle is an event whose only adequate explanation is the extraordinary and direct intervention of God.
- (2) There are numerous well-attested miracles.
- (3) Therefore there are numerous events whose only adequate explanation is the extraordinary and direct intervention of God.
- (4) Therefore, God exists.
If some extraordinary event is a miracle, then it is due to divine agency, and such agency was at work in this event. However, as Peter Kreeft rightly asks, “Was this event a miracle? If miracles exist, then God must exist. But do miracles exist?”  Of course, there are many happenings that count as “extraordinary,” and so, counting those extraordinary events as miracles and thus the intervention of divine agency is a bit of a leap. However, Kreeft rightly recognizes several conditions for being inclined to considering an event a “miracle”:
- (1) The personal setting of the event for an individual.
- (2) The religious context of the event.
- (3) The character and message of the person tied to the event.
(1) and (3) have a close tie with one another, since – even with respect to Jesus Christ – miracles do often (thought not always) involve some given moral authority as well as religious authority which is acknowledged at the occurrence of a miracle. To finish from Kreeft: “[T]here is not really a proof from miracles. If you see some event as a miracle, then the activity of God is seen in this event. There is a movement of the mind from this event to its proper interpretation as miraculous” .
(VIII) The Argument from Reason
C.S. Lewis in chapter 3 of his book Miracles argues that “[a]ll possible knowledge. . . depends on the validity of reasoning” . We trust that our faculties of reasoning are reliable. Lewis believes that we have good reasons for thinking this: “It follows that no account of the universe can be true unless that account leaves it possible for our thinking to be a real insight. A theory which explained everything else in the whole universe but which made it impossible to believe that our thinking was valid, would be utterly out of court” .
C.S. Lewis, arguing against the idea that the entire physical universe (“Total System”) is all there is (i.e., what he calls, ‘Naturalism’). However, given that we believe our faculties are reliable, why can’t they be reliable under naturalism? Lewis, quoting J.B.S. Haldane, writes: “If my mental processes are determined wholly by the motions of atoms is my brain, I have no reason to suppose that my beliefs are true. . . and hence I have no reason for supposing my brain to be comprised of atoms” . As Alvin Plantinga argues, we need a reliable source of reason in order to interpret the world. We consider this reliable source of reason to be God. To finish our argument, consider the following:
- Either at least some of the fundamental causes of the universe are more like a mind than anything else, or they are not.
- If they are not, then it is either impossible or extremely improbable that reason should emerge.
- All things being equal, worldviews that render it impossible or extremely improbable that reason should emerge should be rejected in favor of worldviews according to which it is not impossible and not improbable that reason should emerge.
- Therefore, we have a good reason to reject all worldviews that reject the claim that the fundamental causes of the universe are more like a mind than anything else. 
(IX) The Argument from Beauty (Aesthetic Experience)
To use Alvin Plantinga’s explanation:
- (AB): “On a naturalistic anthropology, our alleged grasp of beauty and appreciation of (alleged) beauty is to be explained in terms of evolution. . . But miserable and disgusting cacophony (heavy metal rock?) could as well have been what we took to be beautiful. On the theistic view, God recognizes beauty; indeed, it is deeply involved in his very nature. To grasp the beauty of Mozart’s D Minor piano concerto is to grasp something that is objectively there; it is to appreciate what is objectively worthy of appreciation” .
However, as I agree with Kreeft: “You either see this one or you don’t” .
(X) The Argument from Religious Experience
Exclusive to your own religious faith may be some sort of experience that points you to a divine reality – at least in the sense that this divine reality is what best explains your religious experience. The argument may be put as follows:
- Many people of different eras and of widely different cultures claim to have had an experience of the “divine.”
- It is inconceivable that so many people could have been so utterly wrong about the nature and content of their own experience.
- Therefore, there exists a “divine” reality that many people of different eras and of widely different cultures have experienced.
Philosopher Richard Swinburne has argued that “[a]n apparent experience (apparent in the epistemic sense) is a real experience (an apparent perception is genuine) if it is caused by that of which it purports to be an experience. My apparent perception of the desk is a real perception if the desk causes. . . light rays to land on my eyes and thereby causes me to have the apparent perception” . Furthermore, he recognizes (despite whether or not they are authentic) that millions and millions of people have once or twice in their lives been aware of God and his guidance. However, he thence furthers the principle of credulity, which says that we ought to believe that things are as they seem to be (in the epistemic sense) unless and until we have evidence that we are mistaken. There are three kinds of evidences:
- (1) Having evidence where our apparent perceptions under certain conditions were actually not reliable.
- (2) We may have evidence in particular cases that things are not as they seem.
- (3) There may be evidence that the apparent experience was not caused by the object purportedly experienced.
To finish on Swinburne’s point: “[I]n the case of religious experiences, as in the case of all other experiences, the onus is on the sceptic to give reason for not believing what seems to be the case. The only way to defeat the claims of religious experience will be to show that the strong balance of evidence is that there is no God. In the absence of that strong balance, religious experience provides significant further evidence that there is a God” .
(XI) The Argument from Common Consent
The argument runs something like this: Common to almost all people of every era is belief in God. Either this vast majority of people have been wrong about this existentially profound element in their lives, or they have not. It is more plausible to suppose that they were not wrong. Therefore, it is more plausible to believe that God exists. This argument in a lot of ways is not a case for theism, but does give one considerable reasons for seeing theism as a credible and serious option.
However, shouldn’t we be mindful of the fact that just because the vast majority says “X is true”, that doesn’t actually make X true? This is to take note that people are not infallible, and so have the possibility of being wrong about some things very little and some things very big. However, as Kreeft notes:
[B]elieving in God is like having a relationship with a person. If God never existed, neither did this relationship. You were responding with reverence and love to no one; and no one was there to receive and answer your response. It’s as if you believe yourself happily married when in fact you live alone in a dingy apartment. Now, we grant that such mass delusion is conceivable, but what is the likely story?. . . It is more reasonable to believe that God really is there, given such widespread belief in him – unless atheists can come up with a very persuasive explanation for religious belief, one that takes full account of the experience of believers and shows that their experience is best explained as delusion and not insight” .
(XII) Pascal’s Wager
French philosopher Blaise Pascal once wrote in his Pensées (‘Thoughts’), “Either God is, or he is not. But to which view shall we be inclined? Reason cannot decide this question. Infinite chaos separates us. At the far end of this infinite distance a coin is being spun that will come down heads or tails. How will you wager?”  The particular reason as to why Pascal says, “[r]eason cannot decide this question”, is because the argument is initially intended for skeptics. Thus, at this “infinite distance” (death) a coin is being spun: heads (God) or tails (no God).
Suppose that none of the prior arguments have convinced you – that they are inconclusive. Pascal believes that there still may be an argument left for those who believe that none of these logical demonstrations work to reach their conclusion. This is known as Pascal’s Wager. So, if we can’t obtain a “proof” for God’s existence (i.e., reason can’t decide), where are you going to place your bet? If you place your bet with God, you don’t lose anything, and you gain infinite happiness. Even if God doesn’t exist and you placed your bets with him, you still lose nothing. But if you place your bet against God, you will lose everything: God, eternity, infinite gain, etc.
The Wager gives us a motive to place our bet: “If there is a God of infinite goodness, and he justly deserves my allegiance and faith, I risk doing the greatest injustice by not acknowledging him” .
(XIII) The Argument from Evil
There is an anti-theistic argument from evil that says there is real evil in the world: “it isn’t just a matter of personal opinion that the thing in question is abhorrent, and furthermore it doesn’t matter if those who perpetrate it think it is good, and could not be convinced by anything we said” . Thus, the evils in this world would constitute a case against the theistic hypothesis that there is an all-good, all-powerful and all-knowing being who intervenes in our world. However, according to the argument, in a nontheistic universe, the opposite is true: evil would just be a natural outgrowth of natural processes.
So, the reasoning is something like this: The naturalist says that evil is a problem for you; why would a good God allow evil to exist? However, evil is still a problem for him: there really isn’t any evil on a naturalistic perspective. “There is nothing much more to evil – say that sheer horror of the Holocaust, of Pol Pot, or a thousand other villains – than there is to the way in which animals savage each other” .
(XIV) The Argument from Simplicity
This is an epistemological argument for God’s existence and runs something like this: according to philosopher Richard Swinburne, God has created us and our “theoretical preferences,” thus leading us to think simplicity has a better chance of being true than does less simplicity. In other words, we are more inclined to think that simple explanations and hypotheses are more likely to be true than long, complex explanations. Hence, if theism is not true, then there is no reason to believe that the simple is more true than the complex.
(XV) The Argument from Desire
We as human beings have desires. Nature cannot explain these desires because nature cannot satisfy them. The source of our desires require a metaphysical source (“above the physical”) to satisfy the desire. These desires can be:
- (1) We have a desire for God.
- (2) We have a desire for life beyond this world.
- (3) We have a desire for ultimate justice.
- (4) We have a desire for meaning/ultimate purpose.
- (5) We have a desire for ultimate truth.
- (6) We have a desire for spiritual significance.
There are of course many other arguments that can be offered that I have not addressed here. However, given the wide variety of arguments available (some modified and newer versions), if they are used carefully and wisely, they make a substantial case for the conclusion that a being such as God exists.
-  From Alvin Plantinga, ed. Deane-Peter Baker (Cambridge University Press: 2007) p. 210
-  Ibid.
-  Ibid.
-  René Descartes, Philosophical Essays and Correspondence (Hackett Publishing: 2000) p. 114
-  Ibid., p. 121
-  Ibid.
-  Timothy McGrew, “The Argument from Miracles,” Blackwell Companion to Natural Theology. ed. J.P. Moreland and William Lane Craig (Wiley-Blackwell: 2012) p. 596. According to McGrew however, “We do not wish to imply that the definition of a miracle as a suspension of physical causation or a violation of physical law is wrong. . . But it is simpler to stipulate that a miracle is an event that would not have happened in the natural order and then to define the natural order as we have done” (ibid.).
-  Peter Kreeft and Ronald K. Tacelli, Handbook of Catholic Apologetics (Ignatius Press: 2009) p. 69
-  Ibid., pp. 70-71
-  C.S. Lewis, Miracles (HarperOne: 1996) p. 21
-  Ibid.
-  Ibid., p. 22. See J.B.S. Haldane’s Possible Worlds.
-  This was taken from Victor Reppert, “The Argument from Reason,” Blackwell Companion to Natural Theology (2012) p. 347. Reppert’s argument differs from other versions of this argument (e.g., argument from intentionality, argument from mental causation, etc.), but it contains qualifications that I think are considerable to the fundamental characteristics of the original argument.
-  From Alvin Plantinga (2007), p. 226
-  Kreeft and Tacelli, Handbook of Catholic Apologetics (2009), p. 87
-  Richard Swinburne, Is There A God? (Oxford University Press: 2010) p. 114
-  Ibid., p. 118
-  Kreeft and Tacelli, Handbook of Catholic Apologetics (2009), p. 90
-  Quoted from Reason and Responsibility, ed. Joel Feinberg and Russ Shafer-Landau (Thomson and Wadsworth: 2005) p. 115
-  Kreeft (2009), p. 92
-  Alvin Plantinga (2007), p. 224
-  Ibid., p. 225