"Gate-crasher," was Alberto's only comment.

"George Berkeley was an Irish bishop who lived from 1685 to 1753," Alberto began. There was a long silence.

Heavy black clouds from the hills to the south were now beginning to gather over the town. The little plane disappeared into the grayness.

Alberto did not reply. He walked across the room and sat down again by the coffee table.

Sophie had already resumed her place. She caught herself biting her nails.

"He's not God Almighty, is he?"

… like a giddy planet round a burning sun…

Alberto walked over to the window facing the town. Sophie followed him. While they stood looking out at the old houses, a small plane flew in over the rooftops. Fixed to its tail was a long banner which Sophie guessed would be advertising some product or local event, a rock concert perhaps. But as it approached and turned, she saw quite a different message: HAPPY BIRTHDAY, HILDE!

"So I'll take the bus home."

"We have to talk about Berkeley," he said after a while.

"I'm afraid there's going to be a storm," said Alberto.

"I only hope the major isn't behind this, too."

"But he was a philosopher as well…"

"Yes?"

"He felt that current philosophies and science were a threat to the Christian way of life, that the all-pervading materialism, not least, represented a threat to the Christian faith in God as creator and preserver of all nature."

"Berkeley was an Irish bishop…" Sophie prompted.

"You'll have to explain that."

"He did?"

"And yet Berkeley was the most consistent of the empiricists."

"He believed we cannot know any more of the world than we can perceive through the senses?"

"More than that. Berkeley claimed that worldly things are indeed as we perceive them, but they are not 'things.'"

"You remember that Locke pointed out that we cannot make statements about the 'secondary qualities' of things. We cannot say an apple is green and sour. We can only say we perceive it as being so. But Locke also said that the 'primary qualities' like density, gravity, and weight really do belong to the external reality around us. External reality has, in fact, a material substance."

"Goon."

"I remember that, and I think Locke's division of things was important."

"How stupid. Look!" Sophie thumped her fist hard on the table. "Ouch," she said. "Doesn't that prove that this table is really a table, both of material and matter?"

"Locke believed -- just like Descartes and Spinoza -- that the material world is a reality."

"Yes, Sophie, if only that were all."

"Yes?"

"This is just what Berkeley questioned, and he did so by the logic of empiricism. He said the only things that exist are those we perceive. But we do not perceive 'material' or 'matter.' We do not perceive things as tangible objects. To assume that what we perceive has its own underlying 'substance' is jumping to conclusions. We have absolutely no experience on which to base such a claim."

"How did you feel it?"

"I felt something hard."

"You had a sensation of something hard, but you didn't feel the actual matter in the table. In the same way, you can dream you are hitting something hard, but there isn't anything hard in a dream, is there?"

"No, not in a dream."

"A person can also be hypnotized into 'feeling' things like warmth and cold, a caress or a punch."

"But if the table wasn't really hard, why did I feel it?"

Sophie had started biting her nails again.

Alberto continued: "According to Berkeley, my own soul can be the cause of my own ideas -- just as when I dream -- but only another will or spirit can be the cause of the ideas that make up the 'corporeal' world. Everything is due to that spirit which is the cause of 'everything in everything' and which 'all things consist in,' he said."

"Berkeley believed in a 'spirit.' He thought all our ideas have a cause beyond our consciousness, but that this cause is not of a material nature. It is spiritual."

"Berkeley was of course thinking of God. He said that 'we can moreover claim that the existence of God is far more clearly perceived than the existence of man."'

"What 'spirit' was he talking about?"

"Is it not even certain that we exist?"

"Yes, and no. Everything we see and feel is 'an effect of God's power,' said Berkeley. For God is 'intimately present in our consciousness, causing to exist for us the profusion of ideas and perceptions that we are constantly subject to.' The whole world around us and our whole life exist in God. He is the one cause of everything that exists. We exist only in the mind of God."

Alberto went on: "Material reality was not the only thing Berkeley was questioning. He was also questioning whether 'time' and 'space' had any absolute or independent existence. Our own perception of time and space can also be merely figments of the mind. A week or two for us need not be a week or two for God…"

Sophie's eyes opened wide with incredulity. Yet at the same time a realization began to dawn on her.

"I am amazed, to put it mildly."

"I cannot see any other possibility. That is perhaps the only feasible explanation for everything that has happened to us. All those postcards and signs that have turned up here and there… Hermes beginning to talk… my own involuntary slips of the tongue."

Sophie continued to bite her nails.

"You said that for Berkeley this spirit that everything exists in is the Christian God."

"So 'to be or not to be' is not the whole question. The question is also who we are. Are we really human beings of flesh and blood? Does our world consist of real things -- or are we encircled by the mind?"

"Is that what you think?"

"Us?"

"Yes, I suppose I did. But for us…"

"For us -- for you and me -- this 'will or spirit' that is the 'cause of everything in everything' could be Hilde's father."

Suddenly the room was filled with a bluish light. A few seconds later they heard the crash of thunder and the whole house shook.

"She is an angel, Sophie."

"Yes, my mind is going round and round, my child. Like a giddy planet round a burning sun."

"Imagine my calling you Sophie, Hilde! I knew all the time that your name wasn't Sophie."

"Hilde is the one this 'spirit' turns to."

"An angel?"

"What about Hilde herself?"

"Are you saying he's been a kind of God for us?"

"To be perfectly candid, yes. He should be ashamed of himself!"

"You could say so."

"What are you saying? Now you are definitely confused."

"And that sun is Hilde's father?"

"Or writes about us. For we cannot perceive the matter itself that our reality is made of, that much we have learned. We cannot know whether our external reality is made of sound waves or of paper and writing. According to Berkeley, all we can know is that we are spirit."

"Hilde is an angel, yes. Let that be the last word. Happy birthday, Hilde!"

"I…"

"And Hilde is an angel…"

"Are you saying that Albert Knag tells Hilde about us?"

One or two cars were plowing through the downpour, but there were no buses in sight. Sophie ran across Main Square and on through the town. As she ran, one thought kept going round and round in her mind: "Tomorrow is my birthday. Isn't it extra bitter to realize that life is only a dream on the day before your fifteenth birthday? It's like dreaming you won a million and then just as you're getting the money you wake up."

"I have to go," said Sophie. She got up and ran to the front door. As she let herself out, Hermes woke up from his nap in the hallway. She thought she heard him say, "See you later, Hilde."

"What's happening to us, little one?"

Sophie ran across the squelching playing field. Minutes later she saw someone come running toward her. It was her mother. The sky was pierced again and again by angry darts of lightning.

Sophie rushed down the stairs and ran out into the street. It was deserted. And now the rain came down in torrents.

When they reached each other Sophie's mother put her arm around her.

"I don't know," Sophie sobbed. "It's like a bad dream."