At the end of his life, Rudolf Steiner dictated a summary of the key ideas that he wished emphasise. These were not finished, but the very last things he wrote about - in a posthumously published book entitled Anthroposophical Leading Thoughts (Collected Works number 26) were some of his most insightful and prophectic statements - although difficult to understand without some background knowledge.
These have been made much clearer by a 2020 book from Jeremy Naydler The struggle for a human future, which I recommend reading.
The following blog post, written earlier today, is my current understanding of what Steiner is implying, but did ot live long enough to formulate and state explicitly.
Anyway, here is an edited excerpt from these final words, which can be seen in full here.
By far the greater part of that which works in modern civilisation through technical Science and Industry — wherein the life of man is so intensely interwoven — is not Nature at all, but Sub-Nature.
It is a world which emancipates itself from Nature — emancipates itself in a downward direction.
Entering the purely earthly element, Man strikes upon the Ahrimanic realm. With his own being he must now acquire a right relation to the Ahrimanic.
But in the age of Technical Science hitherto, the possibility of finding a true relationship to the Ahrimanic civilisation has escaped man. He must find the strength, the inner force of knowledge, in order not to be overcome by Ahriman in this technical civilisation.
He must understand Sub-Nature for what it really is. This he can only do if he rises, in spiritual knowledge, at least as far into extra-earthly Super-Nature as he has descended, in technical Sciences, into Sub-Nature.
The age requires a knowledge transcending Nature, because in its inner life it must come to grips with a life-content which has sunk far beneath Nature — a life-content whose influence is perilous.
Needless to say, there can be no question here of advocating a return to earlier states of civilisation. The point is that man shall find the way to bring the conditions of modern civilisation into their true relationship-to himself and to the Cosmos.
There are very few as yet who even feel the greatness of the spiritual tasks approaching man in this direction.
Electricity, for instance, celebrated since its discovery as the very soul of Nature's existence, must be recognised in its true character — in its peculiar power of leading down from Nature to Sub Nature.
Only man himself must beware lest he slide downward with it.
In the age when there was not yet a technical industry independent of true Nature, man found the Spirit within his view of Nature.
But the technical processes, emancipating themselves from Nature, caused him to stare more and more fixedly at the mechanical-material, which now became for him the really scientific realm.
In this mechanical-material domain, all the Divine-Spiritual Being connected with the origin of human evolution, is completely absent. The purely Ahrimanic dominates this sphere.
In the Science of the Spirit, we now create another sphere in which there is no Ahrimanic element. It is just by receiving in Knowledge this spirituality to which the Ahrimanic powers have no access, that man is strengthened to confront Ahriman within the world.