In this lecture given in 1922, Rudolf Steiner emphasizes the fact that adults in this world are in fact the walking dead. He says "The physical organism is the grave of living thinking, the vessel of dead thinking." Only children have the remnants of living thinking and that is why they require a more creative education. It is also what is meant by the bible verse, that states that unless you become like little children, you cannot enter the kingdom of God. It is our task as human beings to enliven our thinking with spiritual forces and put those thoughts into action through our own will. That is what it means to say, "Thy will be done."
"The fact is that, since the middle of the fifteenth century, people have, upon reaching sexual maturity, experienced an essentially dead form of thinking within themselves. They were filled with the corpse of thought. If you take this thought very seriously, then you will understand that it was only from that time onward that a true inorganic natural science could emerge, because it was only then that human beings began to be able to comprehend purely inorganic laws. Only now could the dead be understood in the way that has been sought since Galileo and Copernicus. The living had to die inwardly first. When people were still inwardly alive in their thinking, they could not comprehend the inanimate externally, for the living mode of cognition imparted itself to the external world. Natural science became ever purer, and this continued until, by the end of the nineteenth century, it was almost nothing but mathematics. That was the ideal toward which it strove: it was to become phoronomy, a kind of pure mechanics.
Thus, in more recent times, the dead have increasingly become the very object of knowledge. That was now the entire pursuit. Of course, this lasted several centuries; but the development follows this line. Genius figures such as de Lamettrie, for example, stated—almost prophetically—that human beings are essentially machines. However, a person who seeks only to comprehend the inanimate makes use only of the mechanical, the inanimate aspect within themselves. This makes the development of the natural sciences easy for modern people. Thinking ceases with sexual maturity. In earlier times, people possessed God-given intuitions, because thinking still retained its capacity for growth far beyond sexual maturity. After reaching sexual maturity, people today lose this living thinking, and so in later life they learn nothing new, but merely parrot what they had already acquired in their early youth.
Now, this was actually quite fitting for the elders who held the reins of culture: to encompass a dead world with dead thinking. It is an excellent way to establish science. But one can never use it to teach and educate the young. And why? Because young people, until they reach sexual maturity, retain the vitality of thought, even if only unconsciously. And so, despite all reflection on the principles of education as they have been formulated in recent times, it is becoming increasingly clear that when rigid, objective science—which encompasses the dead—becomes the educator and approaches the living, youthful, these young people feel it as if a stake were being driven into their flesh. A stake—death—has been driven into their hearts, and they are expected to tear the living out of their hearts. It had to emerge from within human development to reveal what many people still overlook today, yet which is truly and profoundly present: a chasm between old age and youth. And this gulf stems simply from the fact that young people cannot allow the dead stake—which the head devises out of mere intellectualism—to be driven into their living hearts. Young people yearn for a vitality that can only be developed from the spirit through human individuality. And we are taking the first step toward developing this through moral intuitions.
Once you’ve started down that path—as I attempted to illustrate in my Philosophy of Freedom with regard to this purely spiritual realm—for these moral intuitions, distilled from human individuality, are indeed purely spiritual—and once you’ve dared to speak out while others claimed you’d be silenced: lo and behold, the powers that claimed one would be silenced for speaking of moral intuitions are themselves silenced! Thus I appealed to the living, purely spiritual. Science is dead. It cannot bring the mouth to life. But one cannot rely on it anyway. One must appeal to an inner vitality, and only then can one truly begin to seek. The divine lies precisely in this appeal to the original moral and spiritual intuitions. But once one has grasped the spiritual, one can also develop the powers to grasp the spiritual in the broader realms of worldly existence, proceeding from that point. And that is the direct path from moral intuitions to other spiritual contents."
Read more: Rudolf Steiner, Spiritual Forces Working in the Shared Lives of the Older and Younger Generations, Lecture 5, GA 217, 7 October 1922, Stuttgart.