Without god, life has no real meaning. Without an eternal creator of all things, to provide ultimate justice, human life has no relevancy. I cannot think of a world without god in it. What does one have to loose, by accepting Jesus' free gift? If you don't think god exists, just look around you. We are not just here by accident. All these statements have been heard many times over. Quite honestly, I get it. Quite alternatively, if once you die, that is it, or that is all she wrote, then what does it even matter what one does in this life? 300 years from now, no one is probably going to ever be aware of your prior existence, and who really cares! If death is the end and this is true, then what does it matter what one does throughout your earthly life? All such questions raise pause for concern. But does this then mean that the conclusion is a god must exist? Does this also mean that not only does a god exist, but the specific god in which you already believe exists? It appears to become a tug of war between one's intellect verses emotion. Reality leads to some type of emotions, but using the emotion a priori does not usually serve to validate actual reality; unless by random chance.
However, the non-believer in your specific faith is laying down the gauntlet. Rather than interpreting this as a threat, receive it as a challenge. The person opposed to Christianity is doing so, due to lack in evidence for this specific set of beliefs. Many non-believers in the Western hemisphere are actually asking for conversion to Christianity, because they were either raised in it at one point, or are surrounded with it, but honestly cannot currently accept the faith due to lack in demonstration. Presumably, most non-believers do not want to think that when they die, that's the end of it all.
However, in order to continue retaining belief in Christianity specifically, myself included, requires to adhere to at least some of the following attributes outlined directly below. These underlined terms will be directly defined for complete clarity: psychology of belief in god, faith, indoctrination, belief preservation, appeals to emotion, conformation bias, and a need for cognitive closure.
The 'psychology of belief in god' is directly associated with five causes, according to my estimation...
1) The believer possesses a need for control. The uncertainty or presented possible finality for the concept of death demonstrates lack in control. Since the government, police, or any other associated authority, has no control in preventing death, the believer feels a need for control and applies faith to their chosen god.
2) The person feels a need to cope with death. Repeated reminders of one's mortality increase people's belief in the supernatural and also prayer. Continued and repeated readings from the Bible or community gatherings in churches both assert the possibility to life after death, which appears to reduce psychological distress for many. Repetition is key. Re-reading the Bible, while also receiving affirmation from selected authority, via church leaders, offer added comfort and assurance, especially when in doubt or during trying times.
3) Unexplained suffering increases the belief in their proposed god. Ironically enough, suffering often actually increases the tendency for belief in god. The more unexplained the tragedy, the higher the probability the believer will associate the act as god's will. Meaning, a tornado killing an innocent child may be viewed as god's will. Alternatively, someone loosing their job may be from their own accord and is fully explainable; not being necessarily linked to a divine plan.
4) The believer feels the need for justice. Many feel a higher sense for morality if they believe a cosmic deity is watching over all. They also have less tendencies or less of a need to require earthly punishment. Believers feel a higher authority will settle the score in god's chosen time.
5) The battle between experimental thinking versus logical thinking drives many to belief in god. Experimental thinking is associated with the individual in which relies upon their 'gut' feeling in rendering decisions, and is classified as a more emotional decision. The logical thinker more-so makes decisions in a 'matter of fact' manor, void of any personal bias or emotional feelings of any kind. The logical thinker assesses the evidence presented, to determine if the evidence leads to a demonstrated and directly fitting conclusion. As a result, predominant experimental styles in thinking lend higher tendencies for believe in a higher power, verses majoritively logical thinkers.
(To be continued, as there exists a text limit per response)...