In their souls, human beings more and more come to resemble the thought, to resemble that which they regard as knowledge. This will seem a strange truth to the modern mind, but it is so, nevertheless. To see certain things in their proper light, with clarity of thought, with thoughts saturated with reality — that is vitally important.
For example; to regard Darwinism as the one and only valid conception of the world, believing the only possible truth to be that man descends from the animals - that I descend entirely from forces which also produce the animals ... such thoughts, in our age, tend to make the soul resembles its own conceptions of itself.
When the body is discarded, the soul is then confronted with the sorry fate of having to perceive its resemblance with its own thought! A man who lives in the physical body believing that animal forces alone were at work in his evolution, fashions for himself a kind of consciousness in which he will perceive his own likeness to animal nature.
It is ordained that in times to come, what the human being considers himself to be, that he will become.
This development is part of the wise guidance of worlds, in order that the human being may attain full and free consciousness of the Self. On the one side the Gods were bound to make it possible for man to become what he makes of himself; and in order that he might imbue this self-created being with super-sensible meaning, that he might be able to find in this self-created being, something that gives him an eternal aim — in order that this might be, Christ Jesus fulfilled the Mystery of Golgotha.
Harmony with the Self, together with a knowledge which lets man after death be truly man, — this will arise for future times only if human beings become aware, here, in the physical body, of their true connection with the spiritual world.
Those who are afraid of concrete facts of spiritual knowledge because of their materialistic ideas will, of course, for a long time yet be unwilling to acknowledge that any such change took place - nevertheless it will have to be acknowledged sooner or later.
In order to further their aims, the Spirits of Darkness will need to attach particular value to the breeding of confusion among men so that they will not succeed in forming the right thoughts and ideas into which, after death, they are transformed.
What man thinks himself to be, that he is obliged to become...
This is a truth that was destined, after the great changes in the nineteenth century and from then onwards, to find its way to men. The human being must be voluntarily anything that he can be really; he must be able to think about his own being if he is to be truly himself in his life of soul.
Spirits of Darkness, who oppose Man's destiny, inspired human beings to announce the following: “Man is what he eats.” And although this is not, in theory, widely acknowledged, the practical conduct of life amounts very nearly to being an acknowledgement of the principle that man is what he eats — that and nothing else.
Indeed this principle is more and more being applied and developed in external life. To a far greater extent than people believe, the grievous and tragic events of the present time are an outcome of the tenet: Man is what he eats. Humanity is already infiltrated by the principle that “man is what he eats.” And it gives rise, indirectly, to much contention.
That is why the spread of thoughts and ideas corresponding to the realities of the times is so very necessary. Thought will gradually have to be known as a concretely real power of the soul, not merely as the miserable abstraction produced so proudly by the modern age.
Men living in earlier times were still linked, by an ancient heritage, with the spiritual world. Although for many centuries now, atavistic clairvoyance has almost entirely ebbed away, this heritage still lives in the feeling and in the will. But the time has come when everything that is conscious must become a real power — hence the Spirits of Darkness strive to counter really effective thoughts by abstract thoughts in the form of all kinds of programmes for the world.
Thoughts must be imbued with greater and greater reality.
There are still many people who say: “Oh, well, in all good time we shall discover what transpires after death; why trouble about it now? Let us attend to the requirements of life and when we reach yonder world we shall soon discover what it is.”
But if it is true that in yonder world a man becomes what he has pictured himself to be, then something else is also true. For example: A man dies, leaving relatives behind him. Although thought may not be entirely lacking in these relatives, they may be materialistically minded, and then, quite inevitably, they will think either that the dead man is decaying in the grave or that what still exists of him is preserved in the urn.
This thought is a real power; it is an untruth. When those left behind think that the dead man no longer lives, is no longer there; this thought is real and actual in the souls of those who form it. And the dead man is aware of this thought-reality, is aware of its significance for him.
It is therefore a matter of fundamental importance whether those left behind cherish in their souls the thought of The Dead living on in the spiritual world, or whether they instead succumb to the woeful idea that the dead man... well, he is dead; he lies there decaying in the grave.
Edited from Lecture 2 of Behind the Scenes of External Happenings - a lecture given in Zurich, 1917.
I would recommend these two lectures as superb examples of Steiner at his prophetic best - not an easy read, but densely-packed with profound insights and wisdom.