Tracing the course of an empire before it had occurred! Seeing a place that might not ever exist. Talking of sending someone to a place that might never be!
But Caroline was talking now, her cool voice smooth and calm, but with a trace of excitement tinging the tenor of her words.
"You mean you used a geodesic tracer to follow the world line into probability. That you established the fact that in some future time a certain world may exist under such conditions as you saw. That barring unforeseen circumstances it will exist as you saw it, but that you cannot be certain it ever will exist, for the world line you traced could not take into account that factor of accident which might destroy the world or divert it from the path you charted, the path that it logically would have to take.”
"That is correct," said the Engineer. "Except for one thing. And that is that the world will exist as I saw it in some measure. For all probabilities must exist to some extent. But its existence might be so tenuous that we could never reach it… that for us, in hard, solid fact, it would have no real existence. In other words, we could not set foot upon it. For every real thing there are infinite probabilities, all existing, drawing some shadow of existence from the mere fact that they are probable or have been probable or will be probable. The stress and condition of circumstance selects one of these probabilities, makes it an actuality. But the others have an existence, just the same. An existence, perhaps, that we could not perceive.”
"But you did see this shadow of probability?" rumbled Kingsley.
"Yes," said the Engineer, "I saw it very plainly. So plainly that I am tempted to believe it may be an actuality in time to come. But of that I cannot be sure. As I said, it may not exist, may never exist — at least to an extent where we could reach it — where it would have any bearing on our lives.”
"There is a chance, though, that we could reach it?" asked Gary.
"There is a chance," said the Engineer.
"Then," said Herb, impatiently, "what are we waiting for?”
"But," said Gary, "if the universe is destroyed, if we should fail and the universe be destroyed, would that probability still be there? Wouldn't the fact that you saw it prove that we will find some way to save the universe?”