Atheist arguments

This page last updated June 12th, 2023

This page in brief

Atheists have developed many arguments to try to show that the idea of God is incoherent, the world doesn’t look like a world a good God created, and believers only believe by blind faith and not reason based on evidence, and so God cannot exist. How good are the arguments?

I address the following arguments:

In my time discussing with atheists on the internet, I have seen every one of these arguments presented seriously as a reason to disbelieve. My understandings of the arguments and my assessments are based, in part, on some written sources that are included in the reference list at the end of the page.

1. Evil committed by the church

The argument

Down through the history of the christian church, many evil acts have been committed – wars, murder, witch burning, opposition to science, oppression of people (including slaves), etc, right up to present day terrorism. This shows that religion leads to really nasty behaviour, and needs to be eradicated.


This argument doesn’t address the existence of God, only the effects of religion. It contains truth and error mixed together – for example, the church has been guilty of killing and oppression, but so has irreligion; the church only occasionally opposed science in the middle ages and often supported it, etc. Christians have to sadly admit that much that has been done by the church doesn’t live up to the teachings of Jesus, but then, the church has also done much to help those in need and continues to do so. In the end, this argument proves very little about God.

2. Evil and suffering

The argument

The world is full of inhumanity and unspeakable suffering. A good God could not possibly allow so much evil and suffering. The only conclusion can be that there’s no God.


This is surely the strongest argument against the existence of God. It is true that there is much good and beauty in the world and most people are happy with their life. We can recognise that much suffering is a result of human freewill, which is a good thing in itself. We can see that evil provide opportunities for altruism and heroism. But no matter what we say, we still can’t help wondering why a good God allows so much suffering.

Believers are mostly willing to trust God despite the evil, based on the evidence they see for God, but sceptics will generally find this argument compelling.

Look at this argument in more detail in God and evil.

3. Evil in the Old Testament

The argument

There are several Old Testament passages which describe God ordering enemies of the Jewish people to be killed. These commands amount to genocide, it is argued, and could not have come from a good God. This argument opposes belief in the God of Christianity and Judaism, but not God generally.


More liberal christians can dismiss this argument by saying they don’t believe those commands came from God, or that the stories are exaggerated. But more ‘Bible-believing’ christians are faced with a dilemma – either try to justify God’s actions or give up belief in an inerrant Bible. Most try to justify God’s actions, but this tends to make them look like they are indifferent to mass killings. I think it is more reasonable for christians to believe that these stories contain exaggerated and legendary elements.

4. Flying Spaghetti Monster, celestial teapots & Thor

The argument

Believers only believe because they have faith, it is said. But there is no more reason to believe in God than to believe in fanciful and farcical things like the Flying Spaghetti Monster (generally lacking definition, but pretty much what it says), a celestial teapot that hypothetically might be orbiting the sun somewhere out beyond Mars, or the Norse god Thor. So it is just as silly to believe in God as to believe in those admittedly silly things.


This must be one of the silliest arguments against God. There is clearly no serious evidence for these ludicrous objects, as everyone admits, so they can be ignored. But christians believe there is very good evidence for the existence of God, so there is no parallel, no valid analogy, and the evidence for God must be considered on its merits. Even if atheists don’t find the evidence and arguments compelling, they still exist. The only value in this argument seems to be to challenge any christian who thinks faith without evidence is a virtue, or to give atheists something to laugh about.

5. God is an incoherent idea

The argument

Atheists suggest that a number of aspects of the christian God are actually self-contradictory, making it impossible to believe in him. Examples include:

  1. It is impossible for God to be all-knowing (including knowing the future) and all-powerful. Either he knows the future, in which case he cannot change it, or he can change the future, in which case he cannot know it.
  2. It is impossible for God to be perfect and yet know everything. If he is perfect then he cannot know what it is like to sin, but then he doesn’t know everything.
  3. Can God make a rock so heavy he cannot lift it? Whether the answer is ‘yes’ or ‘no’, he mustn’t be all-powerful.
  4. It is impossible for God to be perfect and to have created the universe. If God is perfect he has no needs, so didn’t need to create, and a perfect God wouldn’t have created such an imperfect universe.
  5. It is impossible for God to live ‘outside’ time and to have created the universe. To create, God must exist before the universe, but there is no time for him to exist in. Without time, nothing can happen.
  6. It is impossible for God to be both non-physical and personal. The idea of a bodiless person is inconsistent.
  7. It is impossible for God to be both just and merciful. Justice requires that every person be treated exactly as they deserve, whereas mercy requires that people be treated more favourably than they deserve. The two are incompatible.


It is hard to take these objections seriously. The aspects of God used in the arguments are only human descriptors of a reality that is far beyond our thinking. Define them slightly differently and the problems can disappear. At best, these arguments don’t disprove God, merely show that we cannot fully express God’s character in human definitions – something few christians would disagree with.

  1. Christians believe God is outside time, so there is no such thing as foreknowledge with him. His knowledge of all things accompanies his actions, and neither prevents the other.
  2. Just because God doesn’t experience sin doesn’t mean he doesn’t know about it – he observes it all the time and understands it better than we do.
  3. Philosophers generally define God’s omnipotence in terms of his being able to do anything that is logically sensible. I doubt many believers would be worried that God couldn’t make a rock so big he couldn’t lift it!
  4. Christians believe that God didn’t create the universe out of need, but out of love, which is giving rather than needing. The problem of God creating a universe that is so imperfect is another form of the argument from evil and suffering, discussed above, and this is a strong argument.
  5. We can have no idea how timelessness (eternity) works. Scientists and mathematicians can analyse the possiblity of backwards time, which seems nonsensical, so there is no reason to suppose we can rule out timelessness.
  6. How do we know the idea of a bodiless person is inconsistent?
  7. A person can have two characteristics that can sometimes conflict, and they have to balance the two. God could balance justice and mercy perfectly.

6. I just believe in one less gods than you

The argument

Throughout the world, people have believed in thousands of different gods. Believers generally disbelieve in them all, except one. But using the same reasons for disbelief in all but one God, atheists disbelieve in them all.


This isn’t really an argument so much as a way of drawing attention to the question of why believe in the God of a particular religion rather than another. It is a reasonable question, but christians believe they have good reasons for their choice – see Choosing my religion.

7. Science defeats faith

The argument

Science has a good track record of solving problems, increasing knowledge and helping humanity. Religion has never explained anything, doesn’t build knowledge and harms humanity. The day of religion has passed, and now is the day of science.


Again, this argument doesn’t really address the existence of God, and is based on a mixture of truth and exaggeration. Science has indeed given us some glorious benefits, but it has also helped in making it easier to kill people on a massive scale. Science gives us tools, but doesn’t necessarily help us know how to use them wisely. And it cannot explain many things which form the basis of arguments for the exstence of God (for example, science cannot explain the big bang, or why there is something rather than nothing).

There is a growing feeling in the postmodern world that science has failed to deliver on the big matters of meaning, ethics and humanity. This argument is useful in that it helps push christians towards a greater recognition of the value of science, and the need to assimilate scientific and spiritual knowledge, but it says little about whether God exists or not.

8. The big bang could have turned out differently

The argument

If God wanted to create a universe that produced human beings, he took a big risk, for it was highly likely that the big bang could have proceeded differently, and God’s plan would have been thwarted.


I can’t help feeling this is the most ineffective argument here. If God is all-powerful and all-knowing, he could easily have set up the big bang so that it proceeeded exactly as he intended. In fact that is the basis of the design argument.

9. The inhospitable universe

The argument

The universe is vast beyond imagining, and as far as we know, only minute parts of it are suitable for life – the rest is inhospitable to life and mostly downright dangerous. Surely this proves it couldn’t be designed by God? God is supposed to value human beings yet we are so insignificant, how could we matter to God?


This is another common but weak argument. We (so far) have enough space on earth to live. How can it matter to us if the universe was no bigger than earth, or is as big as it is? And how could it be a problem for an all-powerful God to create the universe as big as it is? The argument just doesn’t have any force.

But there’s more. Cosmologists have calculated that for the universe to exist for long enough for the stars and planets to form and stabilise and life to evolve, it needed to be really vast. So in fact the vastness of the universe is just another evidence that God carefully designed it.

Finally, the size of the human race compared to the universe is irrelevant, unless we can show that importance to God is related to size. God is capable of being closely interested in us, regardless of our size.

10. There is no evidence for the supernatural

The argument

Religion is based on belief in the supernatural, something beyond our natural world – God, angels, heaven, etc. But there is no evidence of these things and no reason to believe they exist.


This is a variation on other arguments here. The argument is based on the assumption that the only evidence that should compel us to believe is scientific evidence. But it ignores the fact that we draw conclusions and take action on many aspects of life – getting married, voting and making political decisions, the study of history, making ethical decisions – without scientific evidence, but still with (hopefully) very good reasons. As with other arguments, we are still faced with the evidence and arguments that christians find convincing. If we find them unconvincing, we choose not to believe, and we shouldn’t need to pretend there’s no evidence at all.

11. Who designed the designer?

The argument

One strong argument for the existence of God is based on the fact that the universe, at its very core and from its very beginning, is amazingly well designed, which implies a designer (see Science and the design of the universe). But, the counter argument goes, we then have to explain how God (the designer) got to be so clever that he could design the universe. If we cannot explain God, then God is not a useful explanation of the universe.


This argument is recognised by most philosophers of science as being quite invalid. We don’t have to be able to explain something for it to be an explanation of something else. If I say I can’t come to the party because I am sick, that is a reasonable expanation, even if we can’t explain why I am sick. If we accepted the logic of this argument, we have no science, because science always explains something in terms of something else, which then has to be understood – for example, the “standard model’ is used to explain many aspects of quantum physics, even though scientists cannot yet explain why the the model is correct.

Besides, philosophers recognise the difference between contingent things (like the universe) which require an explanation and necessary things (like God, if he exists) which don’t. So this argument fails twice.

12. Why is God so hidden?

The argument

God is not visible and the world doesn’t look like he created it, or that he takes an interest in it. If he really existed, and cared about us, God would show himself more clearly so even sceptical people could know he is there, and believe in him.


This argument makes some unsupported assumptions. The world looks to me, and many believers, like it definitely was created by God (without God, it is a mystery how it got here in a state suitable for us to live in it). We appear to have free will and recognise that somethings are truly right and wrong, two things that appear impossible in a world not created by God. And many people say God has healed them, helped them, guided them. Some say he has even pursued them (hence the name ‘the hound of heaven’). So believers say God may not be visible but he certainly is evident. Further, arguing that God would show himself more clearly assumes we can be sure what God is doing, a pretty amazing assumption.

One can understand sceptics wanting more evidence, but on its own, this seems a weak reason to disbelieve. Surely it makes more sense to accept the evidence we have and decide on that basis?

13. A personal conclusion

My assessment is that very few of these arguments have any force. The evil and suffering in the universe is clearly a big problem for believers. The evil in the Old Testament and the ‘hiddenness’ of God are valid thoughts, though there seem to be reasonable responses. But the rest don’t seem to me to have much merit, mostly being built on assumptions, misunderstandings and poor reasoning. The alleged philosophical inconsistencies (which seem to be a favourite form of argument by more educated atheists) just seem to be argumentative curiosities based on arbitrary definitions.

What do you think?

Photo: Wikimedia.

Feedback on this page

Was this page helpful to you? little

Comment on this topic or leave a note on the Guest book to let me know you’ve visited.

Read more about arguments for and against God on this website: