Most people have had enough experience with their senses to know that they can be fooled. We tend to accept shared experiences as real and private experiences as unreal. If I see two trees on either side of my sidewalk when I leave my house every day, and I also know that others see them, I think of them as real trees. But if I wake up remembering a flowering tree that bursts into flame, burns to ashes, and spring anew from the ashes again and again, then I regard that tree as unreal, a mere dream.

At times, though, I have had experiences that were private but very vivid. I can’t say for sure that they were real, yet I do not doubt that they were. In part, I am convinced by the vividness and coherence of the experience. Dreams, I find, tend to fall apart. The more you try to make sense of them, the more they slip into nothingness. But the experiences I am talking about do not fade they way dreams do. They have the same self-authenticating presence as “real” experiences, and yet I have awakened from them.

I think of this when I read the gospel accounts of Jesus transfiguration. Mark, especially, gives us a sense of discontinuity in the experience: “Suddenly, when they looked around, they no longer saw anyone with them except Jesus.” And Luke tells us that the experience was like waking up. I’m sure Peter, James, and John were each glad to have had the other two along to corroborate the experience. It so impressed them that Peter and John both mention it again in their letters. They were eyewitnesses to the glory of Jesus Christ, and heard the voice of God speaking from the bright cloud that came over them.

But what about experiences for which there is no corroborating witness? Is something real if it feels real? Is faith alone meant to sustain us against the dread that we may be dreaming or going mad? How do you know that what you have experienced is real?