Are faith and doubt antonyms? I doubt that.
The Scripture certainly speaks against "doubt", although I am not sure if the Greek word means the same exact thing as we mean by doubt. In context, it is normally speaking of making a conscious decision not to trust or believe. It seems to be more about the absence of faith than the size of it, because Jesus did say - it only takes the faith of a mustard seed.
Normally when we speak of doubt in our current religious context, we mean uncertainty. We aren't using doubt as to refer to decisively not trusting as much as to uncertainty. It is certainly true that most of us never see miracles, even if our friends say they have or know someone who has, or know someone who knows someone who knows someone who has...
For some of us, faith comes much more difficultly. This is due to the root of our faith. If our faith is based upon miracles, and we don't see any, we will lose it. If our faith is based upon God giving us material wealth and possessions, and we lack in those areas, we might lose our faith. If our faith is based upon historical or scientific evidence (which seems to be the prevalent basis for Western apologetics), and the facts we discover seemingly contradict our faith or what we believe about the Bible, then we are quite likely to lose our faith (as many have for this reason).
Jesus said that "they will know us by our fruit" and that we are his because we have love for one another. That is what Shane Claiborne means by "The Irresistible Revolution". When we follow the way of Jesus and the Kingdom of God, loving our enemies and each other, embodying peace and harmony and righteousness in a Christian community, then we will set the foundation for our faith. Following Jesus isn't about certainty, and neither is faith.
Because Jesus did say, "Blessed is the man who sees and believes, but more blessed is the man who does not see and believes".
Uncertainty means not seeing the holes in his hands. It means being faced with a value judgment. In other words, in our current context where knowledge and circumstances are unpredictable, what metanarrative/religion we choose is probably going to have to be based on a value judgment. We will probably have to ask existential questions about our humanity and nature, and go from there into exploring how Jesus' way completes our purpose and fulfills our humanity, making us into holistic human beings again, bringing us back to Eden in a metaphysical sense.
In That Hideous Strength by C.S. Lewis, there is a place that speaks of this sort of thing. The character is being coerced into becoming part of a sketchy organization, being brought through conditioning and brainwashing, and Frost, an antagonistic character, asks him to beat and kick a crucifix while they are in the "Objectivity Room". Here is what follows:
Mark made no reply. He was thinking, and thinking hard because he knew, that if he stopped even for a moment, mere terror of death would take the decision out of his hands. Christianity was a fable. It would be ridiculous to die for a religion one did not believe. This Man himself, on that very cross, had discovered it to be a fable, and had died complaining that the God in whom he trusted had forsaken him - had, in fact, found the universe a cheat. But this raised a question that Mark had never thought of before. Was that the moment at which to turn against the Man? If the universe was a cheat, was that a good reason for joining its side? Supposing the Straight was utterly powerless, always and everywhere certain to be mocked, tortured, and finally killed by the Crooked, what then? Why not go down with the ship? He began to be frightened by the very fact that his fears seemed to have momentarily vanished. They had been a safeguard ... they had prevented him, all his life, from making mad decisions like that which he was now making as he turned to Frost and said,
"It's all bloody nonsense, and I'm damned if I do any such thing."
Amen.