“It appears to me that you first elect your own preference, and then call upon your mind to furnish arguments to support it. It is not bound to do this, and it knows that you rely upon it to suggest any serious danger or difficulty which might impel you to alter your decision, but, no less, it understands your wish, and that if there be any sufficient arguments to justify your choice it is expected to find them. Like your body, it is separate from yourself, and may even work without your own awareness, but it is of a readier loyalty.
“I think, had you for any reason desired to adventure into the mountains, that your mind would have been quick to suggest that you could travel in greater security on the surface if you should avoid the paths which you have traversed already, where the Dwellers would be most likely to seek you. It would have used the argument of the unknown distance in an exactly contrary way, and it would not have failed to remind you that the tunnel which you have already explored contained no possible hiding-place, so that an alternative passage could not be worse, and might be better. It would have recalled that the whole length of the opal pavement is without any possible cover: that the bridge would be difficult for you to traverse in the darkness, while the Frog-Mouths would be dangerous in the day: and that you have already been discovered once in the tunnel, so that it is at least possible that a watch has been set to take you there, should you again invade it.
“I could give you many more arguments of the same kind, but I am not resisting your plan. I am only interested in a method of decision which has, at least, the merit that it can operate more speedily than mine is easily able to do.”
I had not thought her to be slow of decision when the need was urgent, but I felt that she had more to tell me, and I kept my mind open and receptive.
“You slept very long,” her thought continued, “and I considered these things, after my own method. I first collected in my mind all that I have known of the Dwellers from the beginning, and of the things you have told me. I added that which I know of your own character and capacities. From these facts I endeavoured to deduce a method by which we could succeed in our objects, if we be not already too late. I made little progress, for the facts are few and insufficient. But I made progress to this extent, that I realised that we are supposing some things which we do not know.
“In particular, you have shown me your mind, and I have seen that you visualise an end to these tunnels which opens into a hall, a chamber, or a large passage, or at least some public space, populated by the Dwellers, and where concealment for ourselves would be difficult, if not impossible. Your imagination may be correct, and it is a possibility for which we must be prepared. But in your mind it is less a possibility than an expectation, for which there is no sufficient ground whatever. Yet you had imagined it so confidently that I had difficulty in separating it from the facts you had shown me.
“I thought of this very long, and I see that your life is so brief, and so confusingly occupied, that you are obliged to proceed through a labyrinth of assumptions by which you hope to reach the thing you wish more rapidly than would otherwise be possible. But in this case, I cannot see that the assumption has any basis of probability.
“I know, from what you have shown me already, that you come of a race which has lived only on the earth’s surface, and any cave or tunnel by which you enter it implies the approach to a confined and narrow space, so that when you attempt to visualise the condition of a race which lives under the surface, your imagination is of a cave, and not of a country.
“Now if the interior of the earth be completely solid, or nearly so, this imagination may be quite accurate. But is it? Neither of us knows. We do know from your own experience that the tunnels go down for many miles, though we do not know their ultimate depth. That suggests that there must be some reason for so deep a penetration. To make such tunnels must have been a great labour. To descend and ascend them continually must be an unceasing toil. There must be some compensating advantage in the depth which is reached. The hollowness of the interior would supply it. But there might be quite different reasons. We know that there are areas of great heat that lie closely under the surface. There are parts of the ocean floor where this heat causes eruptions. Such areas may be of great extent. They may render it difficult or impossible to live under the surface till a greater depth is reached. True, the tunnels must penetrate this region, on this supposition, and it must therefore have been found possible to render them heat-proof.
“We have one other fact. The Dwellers reach the surface at very distant points. But this has no certain significance.”
I answered, “I see the point you make, and I agree that I was inclined to a too-hasty assumption. Also, it enters my mind that if the earth be indeed hollow at a depth of a few
