As a Christian monotheist, I start with two unproven axioms:
1. There is a God.
2. It's not me (and it's also not you).
Together, these axioms imply my surest conviction: that some of my beliefs (and yours) contain error. We are, from dust to dust, finite and fallible. We have dignity but not deity.
And that is why I further believe that we should
a) hold all our unproven beliefs with a certain tentativeness (except for this one!),
b) assess others' ideas with open-minded skepticism, and
c) freely pursue truth aided by observation and experiment.
This mix of faith-based humility and skepticism helped fuel the beginnings of modern science, and it has informed my own research and science writing. The whole truth cannot be found merely by searching our own minds, for there is not enough there. So we also put our ideas to the test. If they survive, so much the better for them; if not, so much the worse.
Within psychology, this "ever-reforming" process has many times changed my mind, leading me now to believe, for example, that newborns are not so dumb, that electro convulsive therapy often alleviates intractable depression, that America's economic growth has not improved our morale, that the automatic unconscious mind dwarfs the conscious mind, that traumatic experiences rarely get repressed, that most folks don't suffer low self-esteem, and that sexual orientation is not a choice.