But this is the crux of my question; why do we need to "believe" that anything is true, when we can never really logically be certain of it, and we know we can never logically be certain of it? I understand accepting the likelihood that something is true, or very likely to be true until it shows itself not to be. That's logical, and functional.
That is an open question. There's a bomb ticking and you have 10 seconds to sto it from going off. Do you need to believe that you cut the blue wire or the red wire? You know something about how devices are wired and you know red wires tend to carry an electrical current. You know this bomb maker makes bombs that follow designs. In this case you don't know what the bombmaker did. But you need to make a decision. If you do nothing you are dead. Cutting the red wire is most likely to stop the clock, but you aren't certain. You have some information to inform a judgment. You believe cutting the red wire is the right decision.
Compare that to:
Jim was raised in a Baptist church and learned that Jesus is the savior for mankind's sins. Jim learns the Bible and recites texts as part of his faith and devotion. Jim is now 44 and believes Christianity is true, and truth about life and the afterlife. He believes he will be in heaven after he dies. He believes there is a hell for those who deny God, and reject the gift of salvation through His son, Jesus Christ. Jim signs up to a debate forum to share his testimony and through debate he reads that the Bible has been edited, it was cobbled together in the 4th century from about 200 books, that the story of Jesus was likley constructed from pagan and Egyptian lore, that belief in a supernatural is not based on fact and reason, etc. Despite the arguments against belief in what Christianity says Jim has invested decades of his life to belief and faith, he is committed, and he is tied to his faith socially and emotionally. He can't just give it up. He needs his belief in Christianity. It does not matter if his belief is correct or is irrational. As long as his beliefs do not interfere with him functioning in society he can believe whatever he wants.
The way most religions are in the world they are integrated into social and business life. A person can be a scientist and still be a Muslim. The person would have learned to compartmentalize the knowledge of science to the beliefs of religion. He knows not to mingle the two sides of his thinking.
As detailed in the book Emotional Intelligence the human brain evolved an ability to bypass the frontal lobes when thinking about certain ideas. When theists were asked to consider their religious beliefs they were processed in the emotion centers of the brain and bypassed the frontal lobes, which means the brain learned to function in a way to protect its meaning. This is cognitive mapping. It's like a highway of neurons that can go anywhere. Those ideas that are non-rational will avoid the reasoning centers. This might be to avoid stress and emotional pain.
So the need to believe might be a matter of actual survival, but also survival of the ego. We feel pressure to think and believe as we see fit in whatever situation we are in.
So why this need to believe, or to claim to believe? Why this need to ignore the logical fact that the thing we are accepting as being true, may not be, because we can't or don;t know it to be so? Because that's what it means when we say we 'believe in' it. It means that we are dropping our doubts. If it doesn't mean that, then we are misusing the word.
I suspect many theists, especially those who engage in debate, know that their religious beliefs are dubious and not rational. They are likely trapped between their emotional commitment to religion and the reasonable doubt they are aware of. We see many theists justify their belief in the face of skepticism. The thread aboiut homosexuality and religion illustrates this. The Bahai have a doctrine that is prejudical against gays, and they assert their leadership is powerless to change that law. They accept the law and justify it "because it is what God says". Yet the text isn't from a God, it's from a guy who claims to be speaking for God. No God has come forth to verify the text. So it is the believer who is making the decision that the text is validm the Messenger is authentic, and that this God exists and really condemns gays. It's the believer's decision, and it is prejudical and immoral, yet thy try to defer this responsibility to the God. This illustrates how irrational beliefs sabotage a mind.
I realize lots of people misuse words all the time. But that in no way alters my point, here.
Some religions are constantly and deliberately confusing and conflating faith with belief. To everyone's detriment, because it invites confusion and ignorance aself-delusion. Often ON PURPOSE. But that's all the more reason that we should not reinforce their confusion by doing it, ourselves.
Faith and belief have multiple definitions that differ, but they also share a definition, so can mean the same thing. So it is all about using context properly, and not using tricky and misleading language.
Faith is not belief, and belief is not faith. And the difference is CRUCIAL, because the difference is the acknowledgment of skepticism. Faith acknowledges logical skepticism, while belief ignores it. Which is why religions go bad exactly to the degree that they preach that faith IS belief (the rejection of skepticism).
Religious faith and religious belief both ignore skepticsm. Both self-justify.
Secular faith (trust) may be blind to facts or consistent with facts. Let's say Jim has a drug problem and you have been supporting his recovery. He has been clean for 7 months, got a job, and you see this pattern as good and have faith in Jim that he will stay clean and stable. Excellent, you have faith in jim and his commitment to a drug-free life. But one night Jim runs into an old friend and they go to a bar for a drink. Jim gets a little drunk, and the friend offers drugs. Jim's not rational and does the drugs. Jim falls back into the old pattern of behavior. Despite your faith in him he fell off the wagon. You can take these facts and lose faith, or justify more investment. It's all uncertain, faith is a way for us to cope with a lack of control.
The issue here is not the evidence. Anyone can find evidence of anything. The issue is the rejection of logical skepticism, or the acceptance of it.
And logical skepticism tends to work reliable and truthfully. The real issue is why an otherwise rational mind wants to reject logic and sketicism to adopt and accept untrue ideas. Let's say a kid believes in the Tooth Fairy. parents talk about her, and she brings money for your teeth that fell out. That is pretty good evidence. Indisputable. Then your parents confess that it is a fraud, they put the money there. Do you still believe? No, you accepted facts and applied skepticism. But when adults are confronted with septicism about religious beliefs, like Jesus as savior, they reject the facts and logic and keep the faith.