What would it take to change your mind?
An issue that is sometimes raised in debates is what would it take to change your mind? People who answer "nothing" appear to be closed minded and fundamentalist. It is usually a waste of time attempting to reason with such people or show them evidence since they have already declared that their mind will not be changed.
The question is sometimes used to introduce Pascal's wager by claiming belief in God is "safer" than non-belief. Alternatively, an apologist may claim that everyone believes in God, so changing one's mind is not the real issue.
Theists' responses to the question
"Bill Nye and I were asked what would make us change our minds about our beliefs. These two authors believe that I made the “most telling statement of the night” when I said, “No one is ever going to convince me that the Word of God isn’t true.”"
"If somewhere in the Bible I were to find a passage that says two plus two equals five, I wouldn’t question what I’m reading in the Bible. I would believe it—accept it as true and then do my best to work it out and to understand it."
"Trust in the Lord with all your heart, and do not lean on your own understanding."
- Ray Comfort: Peter, could you be wrong about God’s existence?
- Peter Nonacs: Yes. And could you be wrong about God’s existence?
- Ray Comfort: No.
- "When asked what they would do if scientists were to disprove a particular religious belief, nearly two-thirds (64%) of people say they would continue to hold to what their religion teaches rather than accept the contrary scientific finding, according to the results of an October 2006 Time magazine poll. "
Not all believers necessarily share this view. It is difficult to find quotes that illustrate this because having doubts and expressing doubts are discouraged in most religions.
"For Christians, there is only one piece of evidence needed to convert every church into a vacant building and stop printers from producing additional copies of the New Testament. Find the body of that Jewish carpenter, and Christianity is undone."
- — Robin Schumacher 
Skeptical responses to the question
"We would just need one piece of evidence. We would need the fossil that swam from one layer to another. We would need evidence that the Universe is not expanding. We would need evidence that the stars appear to be far away but they’re not. We would need evidence that rock layers can somehow form in just 4,000 years instead of the extraordinary amount. We would need evidence that somehow you can reset atomic clocks and keep neutrons from becoming protons. Bring on any of those things and [...] you would change me immediately."
Apologists question if Nye would really be influenced by evidence as he claims.  This is a tu quoque personal attack because it attempts to deflect attention way from the theist's claim that nothing would change their minds. Another counter argument is that evidence that refutes evolution is already available. This allegedly shows the Nye and other scientists are not willing to accept evidence.  However, claims of disproof of evolution have so far been found to be flawed. Some resources should be allocated to further investigation of these claims and they should not be dismissed out of hand. It is impossible for every scientist to examine every piece of evidence.
"I don't know what would change my mind, and I don't need to know. In fact, it would be arrogant for me to presume that I could even come up with an answer, because that presumes that I'm sufficiently knowledgeable that I can tell the difference between 'a vastly superior technology that is beyond my understanding' and 'the powers of a god'."
It is difficult to establish an intelligent entity exists without being able to directly interact with it. If I tell you about a friend that you don't know and with whom you have no means of communication, it is difficult to establish if this person exists or is only imaginary. If I agree to pass letters between you and my alleged friend, there is still doubt that the friend exists since the letters could be written or modified by the "man in the middle" of the communication. Only direct communication and interaction reliably demonstrates an intelligent entity exists.
"The only way I can be convinced of a god is to know that a god has been observed. Like god suddenly decides to talk to all humans. In a way that overrules hallucination. Then I will be convinced that there is a god."
- — Kaveh Mousavi
Some have listed specific proofs: 
- Verified, specific prophecies that couldn’t have been contrived.
- Scientific knowledge in holy books that wasn’t available at the time.
- Miraculous occurrences, especially if brought about through prayer.
- Any direct manifestation of the divine.
However, it is difficult to see what evidence could be found that distinguishes between a finite and infinite god.
The danger of certainty
Although a feeling of certainty is pleasant,  fixed opinions that are not open to debate are dangerous. It enables control of large groups of people that are willing to commit atrocities while suppressing their individual consciences and judgement.
"In the end, it struck me that the harmful and destructive nature of faiths may be correlated with how much doubt resides in their adherents. [...] The destructive nature of faith stems from certainty: certainty that you know God’s will and God’s mind. It’s that certainty that leads to suicide bombing, repression of women and gays, religious wars, the Holocaust, burning of witches, banning of birth control, repression of sex, and so on. The more doubt in a faith, the less likely its adherents are to do harm to others."
- — Jerry Coyne 
"Certainty has been a loaded gun to the head of humanity for millennia. It is not a "safe" drug. We are in the middle of a vast social experiment with a dangerous psychological pathology. We need more embracing of doubt, fallibility, and skepticism. Telling drug-addicted people that they don't really have a problem only makes the world a more dangerous place."
- — John Shook
Given that we are born knowing very little and we accumulate experiences though our lives, it seems rather rash to form unshakable beliefs on limited evidence. In contrast, fallibilism rejects the possibility of certain knowledge.
A God may be demonstrated but not the Abrahamic God
Some skeptics admit the possibility of evidence for a God but consider that proof of an Abrahamic God, such as described in Judaism, Christianity or Islam, is impossible because it is a self-contradictory concept and therefore cannot exist as it is described. 
A similar position, ignosticism, is to point out that the concept of God has not been coherently defined. The current concept of God has a wide diversity of interpretations.  Many discussions around God assume an entity exists that is self-contradictory or irrelevant to our existence.  Without a clear concept, we cannot discuss God meaningfully.
Standard of evidence
Personal experience of God that cannot be shared with others is insufficient to change some atheist's minds because the experience may be interpreted as a sign of one's own mental illness.  Shared, repeatable, falsifiable, empirical evidence is the only standard considered by some people. Some apparently miraculous phenomena may be extraterrestrial visitors playing a practical joke.  However, given enough evidence of suitable quality, skeptics would admit that the existence of a God (or Gods) of some description was more likely true than false.
If God desired us to believe
- Main Article: Argument from nonbelief
If there is an all powerful God and he desired humans to believe in him, that God knows exactly what it would take to change people's mind. That god would be capable of doing whatever it would take to achieve it. The fact that this hasn't happened can only mean one of two things:
- No such god exists.
- Whatever god exists doesn't care to convince me, at this time.
In either case, it's not an atheist's problem and there's nothing they can do about it.
Antony Flew's Theology & Falsification
Antony Flew argued that theological statements make no assertion as to what cannot possibly happen. Therefore, theological statements are not assertions because there is no evidence that could possibly refute them.
- "Take such utterances as "God has a plan," "God created the world," "God loves us as a father loves his children." [...] But let us confine ourselves to the cases where those who utter such sentences intend them to express assertions.[...] Now to assert that such and such is the case is necessarily equivalent to denying that such and such is not the case. [...] one way of trying to understand (or perhaps it will be to expose) his utterance is to attempt to find what he would regard as counting against, or as being incompatible with, its truth. [...] And if there is nothing which a putative assertion denies then there is nothing which it asserts either; and so it is not really an assertion. "
- "Flew’s challenge was to get the theologian to specify exactly what would have to happen in order for the theologian to give up the claim that God loves us, or the claim that God exists. "
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- Robin Schumacher, What Would Change Your Mind about Christianity?, Confident Christian Blog, 10/17/12
- Answers in Genesis, Would Animals and Plants Found in Unexpected Places Change an Evolutionist's Mind?, Youtube, 14 Apr 2014
- Kaveh Mousavi, What Would It Take to Change Your Mind?, 6 Mar 2014
- The Certainty Bias: A Potentially Dangerous Mental Flaw, Scientific American, Oct 9, 2008
- Jerry Coyne, A confab with the faithful, Why Evolution is True blog, January 30, 2011
- John Shook, Religious Certainty is a Dangerous Weapon, It's Only Natural blog, May 25, 2010