"There is a god."

 

"Humans have a soul."

 

This is a very common problem when debating with theists. Because the topic is often supernatural in nature, it is tempting for them to just state things as fact. To them, it may seem like a fact. But there is a big difference between stating something, and giving a reason why anyone else should believe it is actually true. Anyone can just state anything they like, it would be unreasonable to expect that we should believe everything we are told! That is just being gullible. It is perfectly reasonable to ask for evidence or reasons to back up an assertion. If none are given, then the assertion can be safely dismissed.

 

Often, when asked for an explanation for one assertion, another one is given, and so on. Unless the person can eventually come up with something real and demonstrable to justify this series of assertions, then there's no reason to think it's anything other than wishful thinking on their part.

 

Regarding religion, indoctrination is a big problem here. The strategy is often to bombard children with assertions such as, "God exists", "Jesus died for your sins", "The bible is true" and so on; teaching them as if they are facts. This can leave the child in a state where they really believe these things are true, but cannot rationally defend them because they've never been given any proper explanation. Even as an adult, the person cannot understand why other people do not accept, without justification, these "facts". All you can do is continue to ask for justification. "But what makes you think that is actually true?" They have two options. They can either just continue to assert things, failing to recognize the problem, or they can stop and actually analyze their thinking criticially. The aim of a discussion with theists is often exactly this, to get them to properly think about what they are saying, because they have become so used to saying things as if they need no justification. Hopefully they will realize that they have been assuming there "must be" justification, but that they actually don't know what it is.