I don't rely on faith. I try not to believe in anything that requires me to believe in it, kind of like that old Groucho Marx line, "I would never join a club that would have me as a member."
I don't believe in spirits, souls, gods, angels, or even karma. I don't disbelieve in them either, any more than I actively disbelieve in unicorns or pixies and fairies.
Instead, I like to rely on what I can hear, see, smell, etc. Or theoretically know for myself. For instance, although I have never visited Japan or viewed an electron myself, it is within reason that I could if I tried hard enough. I could travel to Japan or find a laboratory with an electron microscope.
This skepticism, I believe, coincides with the Buddha's teaching regarding faith. We shouldn't believe anything until we have thoroughly questioned and tested it first.
I don't know what will happen after I die, nor do I know why certain events occur. Will I be reborn after I die? Is karma responsible for the circumstances of my life? I do not know. In order to answer in a definitive yes or no, I would have to rely on someone else's experiences, not my own. And this runs counter to what I actually do know to be true--that I am sitting on the couch, chilly from the winter temperature outside, hungry for lunch.
Those things I directly experience. They are here and now and require no speculation on my part. They do not require faith.
Zen practice draws us out of the virtual reality of our thoughts and back into the present moment, back to what we feel, emote, see, taste, and so on. I don't need to have faith that I can raise my left arm. It just happens, free from thought and deliberation--spontaneous, independent of my knowing how it occurs.
It's funny and terribly ironic that so many people, encouraged by religion, spurn what they actually know to be true--the world they live in--to pursue some speculative future after death. They literally pass up what is real for an imagined future, since after all, no one truly knows what happens when we are dead.
I personally would much rather rely on what I actually experience than to place my faith in someone else's teaching.