One of the most important questions for an adherent of Transcendental Realism would have to be, how the Ego constructs the world of ideas out of itself. A world of ideas which was given to us, and which disappeared as soon as we shut our senses to the external world, might provoke an earnest desire for knowledge, in so far as it was a means for investigating indirectly the world of the self-existing Self. If the things of our experience were "ideas," then our everyday life would be like a dream, and the discovery of the true facts like waking. Even our dream-images interest us as long as we dream and, consequently, do not detect their dream character. But as soon as we wake, we no longer look for the connections of our dream-images among themselves, but rather for the physical, physiological, and psychological processes which underlie them. In the same way, a philosopher who holds the world to be his idea, cannot be interested in the reciprocal relations of the details within the world. If he admits the existence of a real Ego at all, then his question will be, not how one of his ideas is associated with another, but what takes place in the Soul which is independent of these ideas, while a certain train of ideas passes through his consciousness. If I dream that I am drinking wine which makes my throat burn, and then wake up with a fit of coughing (cp. Weygandt, Entstehung der Träume, 1893) I cease, the moment I wake, to be interested in the dream-experience for its own sake. My attention is now concerned only with the physiological and psychological processes by means of which the irritation which causes me to cough, comes to be symbolically expressed in the dream. Similarly, once the philosopher is convinced that the given world consists of nothing but ideas, his interest is bound to switch from them at once to the soul which is the reality lying behind them. The matter is more serious, however, for the Illusionist who denies the existence of an Ego behind the "ideas," or at least holds this Ego to be unknowable. We might very easily be led to such a view by the reflection that, in contrast to dreaming, there is the waking state in which we have the opportunity to detect our dreams, and to realise the real relations of things, but that there is no state of the self which is related similarly to our waking conscious life. Every adherent of this view fails entirely to see that there is, in fact, something which is to mere perception what our waking experience to our dreams. This something is thought.