Every existing person is biased. I am making that claim because my life's experience as taught (= biased) me from the neutral perspective (= no perspective at all) to the belief that no person is objective. Maybe I am actually wrong - maybe there are one or more persons in the world that actually are truely objective - but to apply knowledge/belief on the world, one cannot strive for true allknowingness because it's impractical. Somehow, we all have faith all the time. But what we have faith in makes sense and touches our lives significantly.
I have faith not to be killed by a person that walks past me even though I can't know that for sure till I am past it. Practical knowledge. True knowledge... I know that I am writing this right now. I know that I have eyes. I could doubt that, but that would lead me to a point where I become disfunctional, and the mere energy of my will to exist/live impossibilifies too much doubt.
The human mind - as the animal mind - is a bit like a rechargeable battery. It can be loaded, only we're not talking electrical energy but really beliefs. Some beliefs are incompatible with one another, and when the mind has made enough experiences, the contradiction effect (just like the evolution of the species - actually it's the exact same effect) kicks out everything that's not viable, that does not belong.
Religion is also upheld by an evolutionary effect. If you're born into a society that beliefs in religion X v3.4beta, you are likely to be pushed into joining it because of three causes: (1) Religion [has become over time|is designed to be] an assimilator. We are Borg. (2) Social structures (parents, groups, public view) pressures people to give in. (3) People are in need for truth, and religion is fast to replace the truth-seeking-mechanisms of the mind with a cosy warm blindfold that stops all progress of truthfinding. Like a drug that feels good enough to take a part of your life away.
In a society that is mainly into religion X v3.4beta, it is an advantage to join the club. Religion kinda proves the theory of evolution.
What religious people really manage to ignore is the fact that a society that is mainly into religion Y v2.7rc1 mainly spawns members of *that* club. And both clubs (X and Y) claim to be the right one. And the believer doesn't realize that he only got into X because he wasn't born over there in Y-country. A real truth-seeker *must* reject his religion over such an obvious contratiction: It *can't* just be the truth. The other guys are claiming the same for their club!
But the believer used the power of will, and in the mind, this power is really mighty. It is able to create the rock that cannot be lifted by its own creator, the owner of the mind. The rock keeps influencing the mind not to undo it, under no circumstances. Whenever you touch that system/problem at its core, the user (mind-owner) is shaken, but his mere will combined with the rock-bias will strengthen his "belief" (which is really a considerable mind-sickness) so that in the future, said touch won't shake the user any more.
They willingly gave their mind away. Many if not most of them are lost. And that's not just sad, that is even a problem. Because they are convinced of this philosophy of theirs, and this philosophy includes to convince (assimilate) as many people as possible (for example one's own children) into this philosophy.
That's really the funny/dark part there. They collect more and more people, and the mass-effect, guess what, strenghtens their belief. The rock-effect is even in outer reality! No wonder. I mean, people who see God in a gust of wind that shakes a treetop in a "certain" moment are externalizing their belief, they are falling for a mind disease that is close to schizophrenia: The confusion of outer and inner reality.
There is an objective reality. Science is the best way mankind has to deliver true information about that reality to the experiencer(s).
There is virtually a core in the head: The person. Between the outer reality and this perceiving/experiencing/deciding core, there is a thick layer of senses (eyes, ears etc.), the interpretation apparatus/structure and finally all the experiences (memories) that the person made.
This shell between the objective reality and the experiencer is to be kept as clean as possible. To have religious beliefs and uphold them, one has to distort this shell very much.
Science is a tool we use to simulate as good as possible a *perfect* shell (mind). No wonder religious people dislike science. It's so... sane.