And so in this introductory lecture today, we will begin straight-away and without hesitation to speak on a certain chapter of the higher worlds that will lead us to a deeper understanding of man’s character and personality. For after all, what purpose is served by all our studies of the higher worlds? We talk about the astral world, about the devachanic world. In what sense do we members of the physical world talk about them in the first place?
We talk of these higher worlds not at all with the consciousness that they are quite foreign to us and stand in no kind of connection with the physical world. Rather are we conscious that the higher worlds, as we call them, lie all around us, that we live in them, that they project into our physical world, and that in these higher worlds lie the causes and grounds for facts that take place before our physical eyes and senses.
And so we learn to know this life around us with its human beings and nature-events, only when we look at what is invisible but reveals itself in the visible; that is, when we look at what belongs to other worlds in order to be able to form a judgment as to where it plays into our physical world. Normal and abnormal phenomena of ordinary physical life first become clear to us when we learn to know the spiritual life lying behind it — the spiritual life that is far richer and more extensive than the physical life, which forms only a small section of it.
Source: Rudolf Steiner – GA 107 – The astral world: Lecture 1 – Berlin, October 19, 1908