Why Christianity is the one true religion

I'll show you the arguments for the existence of God and then show how Jesus' life is proof of His divinity. Before I begin, I'd like to clarify that God, in the monotheistic sense, is a maximally great being. Zeus and Hades are not Gods in this sense; they are only Gods in the pagan sense, meaning they are supernatural beings with dominion over the world.

Firstly, I would like to disprove the idea of the universe being purely by chance, which I think the teleological argument does best.

The Teleological argument, also known as the fine-tuning argument, is either the best or the worst, depending on who you ask. Personally, I think it makes the existence of life being a random occurrence very unlikely, but I don’t think it definitely proves God’s existence.

1. Within the universe, there are several constants; these constants could not even be slightly different for life to exist. (Examples of constants:

• N – Force Ratio
  N (~10³⁶) is the ratio of electromagnetic to gravitational force between protons. If smaller, gravity dominates and the universe collapses; if larger, atoms can’t form due to strong repulsion.

• Epsilon (ε) – Fusion Efficiency
  Epsilon (0.007) shows how much mass turns into energy during fusion. If too low, fusion fails and only hydrogen exists. If too high, all hydrogen fuses early, leaving none for stars.

• Omega (Ω) – Density Parameter
  Omega (~1) compares actual density to critical density. Too high, and the universe collapses. Too low, and expansion prevents stars from forming.

• Lambda (Λ) – Cosmological Constant
  Lambda (~10⁻¹²²) measures dark energy's effect. If it were even slightly larger, rapid expansion would stop galaxies and stars from forming.

• Q – Density Fluctuations
  Q (~10⁻⁵) reflects early universe lumpiness. Too small, no stars form. Too large, the universe is too violent for stars to survive.

• D – Spatial Dimensions
  D is 3. Life can't exist in 2 or 4 spatial dimensions—only 3 allow stable atoms and orbits.)

2. The fact that all these constants are just right for the formation of life makes it very unlikely that the universe was a product of chance.

3. Because it is abysmally unlikely that these constants are a product of chance, it is much more likely that there is a designer behind the universe and its constants.

The main counterargument against this is the idea that the multiverse is real, and so every possibility of universes with different constants exists, and so, of course, there had to be one where all of them are just right. The problem with this is that there is a very unlikely chance that we would be in the universe that happens to have all the constants right, and also it assumes that there is a sufficient number of universes for every constant to have been tried.
My problem with the argument is that, since God is a maximally great being, there’s no way of knowing that the designer of the universe is a maximally great being, and not just a supernatural being. But I do think that this argument makes the idea that the universe is completely natural extremely unlikely.

St. Thomas Aquinas' Five Ways prove the existence of God. His first way was the argument from motion.

1. We observe things in motion.

2. Movement occurs when potential motion becomes actual motion.

3. Only actual motion can convert potential motion into actual motion.

4. An object's motion cannot be both potential and actual at the same time.

5. Therefore, nothing can move itself.

6. Therefore, everything in motion must be moved by something else.

7. A sequence of motion cannot infinitely regress.

8. Therefore, there must be a first mover.

Some common objections to this argument usually are against the 7th and 8th premises, and they are:
"Infinite regress is possible, therefore there is no need for a first mover."
Infinite regress is impossible because, according to Leibniz's principle of sufficient reason, everything that exists has a reason or explanation as to why it exists. If there is an infinite regress, you can never sufficiently explain why something is in motion, because that thing will always be explained by something else, leaving you with no ultimate and conclusive explanation. If you don't believe in the principle of sufficient reason, infinite regress still is impossible because, without a first mover, no motion could ever begin, but because we can observe motion, there was a beginning.

The other objection against the 8th and final premise is that: "Just because there is a first mover, that doesn't require It to be God."
This is false because, since we have determined there to be a first mover, this being must be fully actual. Because if It had potential for motion, It would not be the first in the sequence of movers. Because It is fully actual, It does not have the potential to be greater, therefore It must be maximally great. God is a maximally great being, therefore the first mover is God.

The second way is similar to the first, but it essentially says that X cannot cause itself, therefore something caused X to exist. If the cause doesn't exist, then neither does the effect. Therefore, if there is no first creator, then there would be no X. There is X, therefore there is a creator.

The third is also quite similar.

1. We find in nature things that are possible to be and not to be: contingent beings.

2. Everything is either necessary or contingent.

3. Assume that everything is contingent.

4. It is impossible for contingent beings always to exist, for that which can not be at some time is not.

5. Therefore, by (3) and (4), at one time there was nothing.

6. That which does not exist begins to exist only through something already existing.

7. Therefore, by (5) and (6), there is nothing now.

8. But there is something now.

9. Therefore (3) is false.

10. Therefore, by (2), there is a necessary being: God.
    I won’t present the last two because I don’t think they sufficiently work as an argument for God’s existence.

The moral argument for God can be presented in two ways. One is very simple:

1. Without the existence of God, there is no morally good and morally evil.

2. There is morally good and morally evil.

3. Therefore, God exists.

And then there's the more complex version:

1. Morality is a rational endeavour. This means that, when deciding what is morally good, we use our rationality and reason. We don't decipher our morality from empirical evidence; for example, you don't need to watch someone be murdered to know murder is wrong.

2. Moral facts and duties exist. Meaning that morality is something as true as mathematics or science. This premise is true because we assume certain duties, whether independent of morality or not. For example, we should not kill people, whether it be right or wrong. But there is no reason for us not to kill people unless it is wrong, and so by assuming we shouldn't do something, we are assuming it is wrong.
   Another argument for moral realism is from our intuition: when we see something we perceive to be wrong, for example, genocide, which we condemn to be evil, but if we are moral relativists, why can we force our beliefs on others based on our subjective opinion? We can't, and so for us to condemn anything, we must assume objective morality. But why would we assume this if there is no God? There would be no reason to assume any sort of morality if God does not exist. An argument against this is the idea that our sense of morality comes from evolution, that we assume murder to be wrong because murder negatively affects our chances of survival, as we would not be trusted among our tribe. But this counterargument fails to account for certain things. For example, paedophilia—there is no evolutionary reason as to why we assume paedophilia to be immoral, as it poses no threat to our survival, but we still know it to be wrong. Why? Same with the example I brought up, genocide—the genocide of another group does not affect our survival and could be beneficial towards the survival of our own group, but we still condemn the people who do it. This is because we all have a deep intuition of what is right and wrong, that is ingrained into us, separate from religion.

3. Humans are not the foundation of this moral truth. We know this because, if we were, we would have complete knowledge of what is right and wrong, but there are disagreements on morality, such as moral dilemmas, and so we can know that this sense of moral intuition does not come from ourselves.

4. Because we know that moral truths are real, for them to be real they must be grounded in something necessary and unchanging. This unchanging being must be a conscious, rational being, based on the 1st premise.

5. This source of morality is God.

The final argument for the existence of God is Alvin Plantinga’s Modal Ontological argument. This, in my opinion, is the best, because it definitively proves God’s existence with 100% certainty, while some of the other ones only make it more likely for God to exist. This is the argument that convinced me to become a theist.

1. It is possible that God exists. We can know this because the only things that are impossible to exist are logically incoherent things. For example, a 3-sided square cannot exist ever, because its own nature contradicts itself. While the concept of God is not logically incoherent.

2.  If it is possible that God exists, He exists in some possible worlds. (When possible worlds are mentioned, it's referring to a hypothetical universe, and not anything within our universe or the multiverse.)

3.  God is a maximally great being.

4.  A maximally great being is not maximally great if it only exists within some possible worlds.

5. Therefore, if God exists within some possible worlds, God exists within all possible worlds.

6.  If God exists within all possible worlds, God exists within the actual world.

7.  Therefore, God exists.

The only way to debunk this argument is by attacking the first premise, because if the first premise is true, all the other premises follow naturally, which most atheists accept. Many counterarguments strawman the ontological argument by comparing God (a necessary being) to contingent beings, such as Bigfoot or unicorns. The rebuttal usually goes: “The definition of unicorn is a horse-like being with one horn that exists; therefore, unicorns exist” as a way of showing that defining God as existing does not make Him exist. But this misrepresents the argument because the argument does not begin by saying that God exists, but instead defines Him as a maximally great being, and then concludes from that that He exists. You might say that God is not a maximally great being, but that doesn’t matter, because you can call a maximally great being whatever you want. This argument proves the existence of a maximally great being, which we call God; you can call it whatever you want, but the theological definition of God is that He is maximally great.
The argument that God is a logically impossible concept and so He cannot exist in any universe is quite common, and if you’ve studied any theology, you’ve probably heard of it.
“Can God create a rock so heavy that even He cannot lift it? If He can, because He can’t lift it, He is not omnipotent, and if He can’t, that is something He can’t do, also making Him not omnipotent.”
This counterargument fails to understand the nature of God’s omnipotence. Omnipotence means you have unlimited power, which in turn means you can do everything. A rock so heavy an omnipotent being could not lift it is a contradiction, because an omnipotent being can lift everything. A contradiction is not a thing, because it is, by its own nature, logically impossible within all possible worlds, and so if omnipotence means you can do everything, and a rock so heavy an omnipotent being could not lift it is not a thing. That means that God being unable to do a non-thing is no limit to His omnipotence.
There are many arguments against the ontological argument that are similar to this, in that they fail to understand omnipotence, omniscience, or unlimited benevolence. For example, “Can God commit evil? Because if He can, He is not all-benevolent, and if He can’t, He is not omnipotent.” This is false because a fully benevolent being committing evil is a contradiction, and so it does not fall under God’s omnipotence.

So now that I have proved the existence of a maximally great being, I am going to give you reasons to believe the New Testament is a reliable source, to then prove, using this source, that Jesus Christ of Nazareth rose from the dead, and that that proves He is God. First and foremost, I would like to mention that there was no single entity that had control over the biblical manuscripts. The Christian church initially was a persecuted minority, which didn’t have enough power to unilaterally change all existing documents of the New Testament, which there were 5,800 copies of in Greek, 10,000 in Latin, and roughly 9,300 in other languages, such as Syriac, Slavic, Gothic, Ethiopic, Coptic, Nubian, and Armenian. To put this into perspective, Homer’s Iliad has roughly 1,800 surviving manuscripts, yet most rational people still believe the Iliad to be written by Homer.

The oldest full New Testament copy is Codex Sinaiticus, a Greek manuscript written in the mid 4th century AD. The oldest fragments we possess are Papyrus 52, Papyrus 90, and Papyrus 104, which are all dated 100–200 AD.

The manuscripts of the New Testament are dated closest to its original copy more than any other ancient document, so for us to doubt the New Testament, we also must apply even more doubt to the works of Plato and Aristotle. Textual variants in different manuscripts have been used to try and prove that the Gospel is not reliable, however, the majority of these differences are insignificant, such as spelling or grammar.
There is also the claim that the New Testament was altered after Jesus’ death and when the Gospels were written, since they were written so long after.
The reason we date Mark’s Gospel to 70AD is because in Mark’s Gospel, Jesus speaks of the destruction of the temple in Jerusalem (Mark 13:1-2) and the persecution of Christians (Mark 13:11-13), which both took place around 70AD, which means Mark’s Gospel must have been written after those events. Matthew and Luke used Mark as a source, which means they were written after.
If Mark’s Gospel was written after the destruction of the second temple, it would make sense for him to use more specific language to make it more convincing, instead of the hyperbolic language we see used in Jesus’ description of the event. There are also other things that we would have expected Mark to have written about if it was written after the fact, such as the fact that Christians fled to the city of Pella, despite Jesus having told them to flee to the mountains, or that Jesus told them to pray it does not happen in the winter, but the destruction happened in the summer. It would not make sense for Mark to write down these things when, if he already knew of the events of the second temple, he could have written them down much more accurately.
Nowhere in the Gospel does it describe the destruction of the temple as a past event, it does prophesy its destruction, but if it was written after, you would expect there to be some mention of the fact that Jesus’ prophecy actually came true. Another thing you would expect Mark to have mentioned would be Paul’s death in 64-65AD, or Nero’s persecution of Christians, which there is no mention of. On other matters, such as Judas’ eventual betrayal of Jesus, it is mentioned what Judas would end up doing, obviously because it was written after, so they knew what would happen when they were writing it. But they did not do this with the destruction of Jerusalem; they only warned about what will happen, but why warn people about an event that has already happened? This gives us good reason to believe the Gospels are dated pre 64-70AD.
My final point on this matter is that the Gospels express many Semitic phrases, for example, “The Son of Man” or “Eloi, Eloi, lema sabachthani?”. This is important because after the destruction of Jerusalem, there was a shift in culture, Judaism massively changed, and paganism became more prominent. The usage of Semitic phrases makes it more likely that the Gospels were written before this shift in culture.
Obviously, the Gospels being reliable does not mean what the Gospel proclaims is true, but at least now we can know that what the New Testament claims is what the Apostles claimed.

There is a nonsensical claim that is popular today, that Jesus never claimed to be God. Jesus never directly said “I am God”, because He revealed it in other ways. One of Jesus’ hints to His divinity is in the book of Mark, specifically Mark 2:1-12, which goes:

And when He returned to Capernaum after some days, it was reported that He was at home. And many were gathered together, so that there was no more room, not even at the door. And He was preaching the word to them. And they came, bringing to Him a paralytic carried by four men. And when they could not get near Him because of the crowd, they removed the roof above Him, and when they had made an opening, they let down the bed on which the paralytic lay. And when Jesus saw their faith, He said to the paralytic, “Son, your sins are forgiven.” Now some of the scribes were sitting there, questioning in their hearts, “Why does this man speak like that? He is blaspheming! Who can forgive sins but God alone?” And immediately Jesus, perceiving in His spirit that they thus questioned within themselves, said to them, “Why do you question these things in your hearts? Which is easier, to say to the paralytic, ‘Your sins are forgiven,’ or to say, ‘Rise, take up your bed and walk’? But that you may know that the Son of Man has authority on earth to forgive sins”—He said to the paralytic—“I say to you, rise, pick up your bed, and go home.” And he rose and immediately picked up his bed and went out before them all, so that they were all amazed and glorified God, saying, “We never saw anything like this!”

Jesus was a 1st-century Jew. He obviously would have known that it is blasphemy to forgive sins if you are not God. So when He claims to have forgiven the sins of the paralysed man, He is claiming to do something only God can do, implying He is God.

John 10:22-30 (ESV) - At that time the Feast of Dedication took place at Jerusalem. It was winter, and Jesus was walking in the temple, in the colonnade of Solomon. So the Jews gathered around Him and said to Him, “How long will You keep us in suspense? If You are the Christ, tell us plainly.” Jesus answered them, “I told you, and you do not believe. The works that I do in My Father’s name bear witness about Me, but you do not believe because you are not among My sheep. My sheep hear My voice, and I know them, and they follow Me. I give them eternal life, and they will never perish, and no one will snatch them out of My hand. My Father, who has given them to Me, is greater than all, and no one is able to snatch them out of the Father’s hand. I and the Father are one.”

This is the most clear passage alluding to Jesus being God. The Father is referring to God the Father, the Head of the Trinity. Jesus claiming that He and the Father are one does not imply that They are the same, but that They are both in unity, and of the same worth.

A counterargument to Jesus' claim of divinity is in Mark 10:17-22.

And as He was setting out on His journey, a man ran up and knelt before Him and asked Him, “Good Teacher, what must I do to inherit eternal life?” And Jesus said to him, “Why do you call Me good? No one is good except God alone. You know the commandments: ‘Do not murder, Do not commit adultery, Do not steal, Do not bear false witness, Do not defraud, Honour your father and mother.’” And he said to Him, “Teacher, all these I have kept from my youth.” And Jesus, looking at him, loved him, and said to him, “You lack one thing: go, sell all that you have and give to the poor, and you will have treasure in heaven; and come, follow Me.” Disheartened by the saying, he went away sorrowful, for he had great possessions.

The important part of this is when Jesus says, “Why do you call Me good? No one is good except God alone.” Now, at first, this seems like Jesus is denying that He is God. As it appears as if Jesus claims that He is not good, only God is, however that is not what He is trying to communicate. The meaning of what He said is that if the rich young man thinks that Jesus is good, he must then accept that Jesus is God. Jesus did not deny that He is good; if Jesus thought He was not good, He would have said, “Why do you call Me good? I am not good, no one is good except God alone.” But He didn’t; He only questioned the rich young man into realising the implications of Jesus’ goodness.

And my final point on this matter is that Jesus never corrected the disciples when they called Him God. Thomas calls Jesus “My Lord and my God” in John 20:28, and there are many times when Jesus had to correct the disciples on certain matters, for example Mark 9:33-37 and Luke 22:24-27, however when one of the disciples calls Jesus “My Lord and my God”, Jesus does not correct him.

But Jesus’ claim to be God are meaningless unless he proved His claim, and He did this in the form of miracles. Miracles are the best way of Jesus proving His claim because it proves He has dominion over the natural world, and is not bound by them as regular humans are. The most important miracle was His Resurrection. If the resurrection happened then Christianity is true, since the entire basis of Christian belief is that Jesus Christ rose from the dead.

Two things we know about Jesus is that He was crucified, and that people claimed to have witnessed Him alive after His death.

The most common non-Christian argument to explain the fact that people claimed to have seen the risen Jesus, is that the story of the New Testament was a lie made by the disciples. The main and obvious problem with this theory is that there were no incentives to lie, when people lie, it is almost always done to gain something good or to escape something bad, but many of the disciples were killed in brutal ways for example, crucified (Peter, Andrew, Philip), beheaded (James the Greater), speared to death (Thomas), flayed alive (Bartholomew), stabbed to death (Matthew), beaten to death with a club (James the Less), boiled alive but survived (John). All these people were killed or tortured for their faith, which means that if they were intentionally lying, they did so for no reason and it only negatively affected themselves. That’s why this theory makes zero sense. A response to this is that people of other faiths will also die for their religion, but my claim here is that the people who wrote the gospel or knew Jesus are not liars, not that they are correct. I doubt any Muslim or Jewish martyrs are intentionally lying, but I don’t believe they are correct.  The difference is that the Christian martyrs I mentioned knew Jesus, so they would of known if his miracles and divinity were fake or not, whilst the Muslim martyrs who knew Muhammad, because Muhammad had no miracles that are mentioned in the Quran (except splitting the moon), there was no way of knowing if Muhammad was actually a prophet, so the Muslim martyrs that knew Muhammad died for something they were told was true, but the Christian martyrs died for something they would've known to be false.

Another problem with this theory is that there are many things within the story of Jesus’ Resurrection that wouldn’t make sense for a first century Jew to claim if they wanted their lie to be believed. Why would they claim that Mary Magdalene was the first witness of the empty tomb and risen Jesus if a woman’s testimony was not considered reliable back then? Maybe because Mary Magdalene was actually the first witness and they were not lying. What about their Messiah being killed? Your own God being tortured and killed was considered very embarrassing in the 1st century, for Jews and Pagans, as the Messiah was supposed to be seen as a conqueror. It wouldn’t make sense for anyone to claim that if they wanted their lie to be credible. Same goes for the the authors admitting that they were afraid, confused or weak (e.g. Mark 9:32, Matthew 26:69-75, Mark 14:50) which is not common in documentation of an event around that time, as the author usually tried to depict themselves as heroic or bold. They only would of added these details in if they had a genuine desire to tell the truth as to what actually happened.

The other most common claim among skeptics deals with these problems by saying that the people who claimed Jesus rose from the dead were not lying, but that they were deluded into believing He did. For the witnesses of the risen Christ to have been delusional, you would need over 500 people all to be collectively deluded so much so that they were willing to be killed for this delusion. If they were hallucinating it would take multisensory mass group hallucination, which would take a miracle to happen. It also fails to explain the empty tomb. The argument that tries to explain the problem of the empty tomb is the idea that Jesus survived the resurrection. There is only one account of anyone having survived roman crucifixion, when emperor Titus ordered the removal of three men from the cross, two of which died later. the one who survived was provided with medical care. Jesus was tortured by the romans prior to his crucifixion, forced to carry a 300 pound cross up a hill, stabbed in the side by a lance and was crucified for 6 hours. He received no medical care, and when he appeared to the disciples, he appeared completely fine, except the holes in his hands. The first thing he said was "Peace be with you". If all of those things were done to you, and somehow you managed to survive, first of all you would not be in a perfect physical and mental condition, and you would be asking for medical care instead of preaching. Many of these theories that try to explain the facts surrounding resurrection require miracles themselves to be true. The only theory that explains the the disciples martyrdom, Mary Magdalene as the first witness, the empty tomb, Jesus' posthumous appearances and perfect condition after crucifixion, is that Jesus Christ of Nazareth rose from the dead. It's what all the people who witnessed it believed, it's what converted the pagan nations, and most importantly it is in accordance with the scriptures.

Of course this is not the entire case for Christianity. This is just proof of Christianity's primary claims. If you found this convincing I would recommend you look into it yourself, as I am not the best apologetic or evangeliser.