the intellect is not a truth-seeking tool. people use their rational mind to believe anything. there is a single god. god is a trinity, there are many gods. there is no god. obama is a horrible president. he is a great president. the intellect is a filter for hiding evidence that doesn't fit the nearly-hidden theories and biases the individual holds and generally shares with his group. the intellect is a tool of culturization, to synchronise the individual with the culture, allowing him to see and firmly believe the same things everyone else believes, to fit in, to be one of us.
the human intellect emerges around age 6, or so. it was unneeded to create the human body. it is unneeded to heal a cut. it is unneeded to walk down the street, to breathe the air, to shoot a basketball. it awakens and takes control, or believes it does. it ignores all evidence that does not fit the guiding beliefs.
the intellect projects into the future every negative trend. it thinks, if something is wrong now, it can only get worse. this is in the face of contrary evidence. scientists have advanced this view into a grand theory they call entropy. all the energy available in the universe was created in the beginning and everything is devolving into chaos. au contraire, the evidence suggests every system continually becomes more complex. there must be an unknown source of energy driving systems to ever great sophistication, because that is the evidence.