"Scope," Mentor replied, gravely. "Each of those qualities and characteristics must be expanded to encompass the full sphere of thought. Neither words nor thoughts can give any adequate concept of what it means; a practically wide-open two-way will be necessary. This cannot be accomplished, daughter, in the adolescent confines of your present mind; therefore enter fully into mine." She did so: and after less than a minute of that awful contact slumped to the floor. * * * * * The Arisian, unchanged, unmoved, unmoving, gazed at her until finally she began to stir. "That ... father Mentor, that was--" she blinked, shook her head savagely, fought her way back to full consciousness. "That was a shock." "It was," he agreed. "More so than you think. Of all the entities of your Civilization, your brother and now you are the only ones it would not kill instantly. You now know what the word 'scope' means, and are ready for your last treatment, in the course of which I shall take your mind as far along the road of knowledge as mine is capable of going." "But that would mean ... you're implying--But my mind _can't_ be superior to yours, Mentor! Nothing could be, _possibly_--it's sheerly, starkly unthinkable!" "But true, daughter, nevertheless. While you are recovering your strength from that which was but the beginning of your education, I will explain certain matters previously obscure. You have long known, of course, that you five children are not like any others. You have always known many things without having learned them. You think upon all possible bands of thought. Your senses of perception, of sight, of hearing, of touch, are so perfectly merged into one sense that you perceive at will any possible manifestation upon any possible plane or dimension of vibration. Also, although this may not have occurred to you as extraordinary, since it is not obvious, you differ physically from your fellows in some important respects. You have never experienced the slightest symptom of physical illness; not even a headache or a decayed tooth. You do not really require sleep. Vaccinations and inoculations do not 'take'. No pathogenic organism, however virulent; no poison, however potent--" "Stop, Mentor!" Kathryn gasped, turning white. "I can't take it ... you really mean, then, that we aren't human at all?"