My companion answered with her usual equanimity, “It is a choice which must be made, and your decision contents me. But I notice a quality in your reasoning which must, I suppose, introduce the adventure of your life to many avoidable difficulties. I think the arguments which you gave me were good, but they did not cover all the considerations which might influence such a decision, and of which I feel sure you could have thought, had you wished to do so. “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.