This extract needs its context so the following reference from Steiner is a long one.
 
Here I reach a point that is most important for those who would undergo an occult development in their own souls. I want to make every effort to get this point clear. The medieval alchemists used to say — I cannot now discuss what they really meant by it — that gold could be made from all metals, gold in any desired amount, but that one must first have a minute quantity of it. Without that one could not make gold. Whether or not this is true of gold, it is certainly true of clairvoyance. No man could actually attain clairvoyance if he did not have a tiny amount of it already in his soul. It is generally supposed that men as they are, are not clairvoyant. If that were true they could never become clairvoyant at all, because just as the alchemist thought that one must have a little gold to conjure forth large quantities, so must one already be a little clairvoyant in order to be able to develop and extend it more and more. Now you may see two alternatives here and ask, “Do you think then that we all are clairvoyant, if only slightly, or, do you think that those of us who are not clairvoyant can never become so?” This is just the point. It is most important to understand that there is really no one among you who does not have this starting-point of clairvoyance, though you may not be conscious of it. All of you have it. None of you is lacking in it. What is this that all possess? It is something not generally regarded or valued as clairvoyance. Let me make a rather crude comparison.
If a pearl is lying in the roadway and a chicken finds it, the chicken does not value the pearl. Most men and women today are chickens in this respect. They do not value the pearl that lies there in full view before them. What they value is something quite different. They value their concepts and ideas, but no one could think abstractly, could have thoughts and ideas, if he were not clairvoyant. In our ordinary thinking the pearl of clairvoyance is contained from the start. Ideas arise in the soul through exactly the same process as what gives rise to its highest powers. It is immensely important to learn to understand that clairvoyance begins in something common and everyday. We only have to recognize the supersensible nature of our concepts and ideas. We must realize that these come to us from the supersensible worlds; only then can we look at the matter rightly.
When I tell you of the higher hierarchies, of Seraphim and Cherubim and Thrones, right down to Archangels and Angels, these are beings who must speak to the human soul from higher spiritual worlds. It is from those worlds that concepts and ideas come into the human soul, not from the world of the senses. In the 18th century what was considered a great word was uttered by a pioneer of thinking, “O, Man, make bold to use thy power of reason!” Today a great word must resound in men's souls, “O, Man, make bold to claim thy concepts and ideas as the beginning of thy clairvoyance.” What I have just expressed I said many years ago, publicly in my books Truth and Science and The Philosophy of Freedom, where I showed that human ideas come from supersensible, spiritual knowledge. It was not understood at the time, and no wonder, for those who should have understood it were — well, like the chickens! We must realize that at the moment when Krishna stands before Arjuna and gives him the power of abstract judgment, he is thereby giving him, for the first time in the whole of evolution, the starting-point for the knowledge of higher worlds. The spirit can be seen on the very surface of the changes that take place within the external world of sense. Bodies die; the spirit, the abstract, the essential being, is eternal. The spiritual can be seen playing on the surface of phenomena. This is what Krishna would reveal to Arjuna as the beginning of a new clairvoyance for men.
One thing is necessary for men of today if they would attain to an inwardly-experienced truth. They must have once passed through the feeling of the fleeting nature of all outer transformations. They must have experienced the mood of infinite sadness, of infinite tragedy, and at the same time the exultation of joy. They must have felt the breath of the ephemeral that streams out from all things. They must have been able to fix their interest on this coming forth and passing away again, the transitory conditions of the world of sense. Then, when they have been able to feel the deepest pain and the fullest delight in the external world, they must once have been absolutely alone — alone with their concepts and ideas. They must have had the feeling, “In these concepts I grasp the mystery of the worlds; I take hold of the outer edge of cosmic being,” — the very expression I once used in my The Philosophy of Freedom! This must be experienced, not merely understood intellectually, and if you would experience it, it must be in deepest loneliness. Then you have another feeling. On the one hand you experience the majesty of the world of ideas that is spread out over the All. On the other hand you experience with the deepest bitterness that you have to separate yourself from space and time in order to be together with your concepts and ideas. Loneliness! It is the icy cold of loneliness. Furthermore, it comes to you that the world of ideas has now drawn together as in a single point of this loneliness. Now you say, I am alone with my world of ideas. You become utterly bewildered in your world of ideas, an experience that stirs you to the depths of your soul. At length you say to yourself, “Perhaps all this is only I myself; perhaps the only truth about these laws is that they exist in the point of my own loneliness.” Thus you experience, infinitely enhanced, utter doubt in all existence.
When you have this experience in your world of ideas, when the full cup of doubt in all existence has been poured out with pain and bitterness over your soul, then only are you ripe to understand how, after all, it is not the infinite spaces and periods of time of the physical world from which your ideas have come. Now only, after the bitterness of doubt, you open yourself to the regions of the spiritual and know that your doubt was justified, and in what sense it was justified. For it had to be, since you imagined that the ideas had come into your soul from the times and spaces of the physical world. How do you now feel your world of ideas having experienced its origin in the spiritual worlds? Now for the first time you feel yourself inspired. Before, you were feeling the infinite void spread around you like a dark abyss. Now you begin to feel that you are standing on a rock that rises up out of the abyss. You know with certainty, “Now I am connected with the spiritual worlds. They, not the world of sense, have bestowed on me my world of ideas.”
(http://wn.rsarchive.org/Lectures/OccultGita/19130529p01.html)

The significance of the pearl in this lecture will be obvious to those who have studied the TAO path indicated in T H Meyer’s book: Clairvoyance and Consciousness – The Tao Impulse in Evolution (1991, London: Temple Lodge Press).  The wisdom of the spirit comes into Earthly perception in droplets “Like dew upon the grass” as we hear in the old carol, “I sing of a maiden”. There we hear of the maiden, Sophia and “He came all so still” who is symbolised in medieval times as the unicorn.