Synthesized answer
The "thing" that craves utterance but is never said is described as something "graver, deeper, more human, more real than friendship, pity or love." It is "piteously flapping its wings at the back of our throat," and is crushed by our ignorance [1]. This suggests a profound, inexpressible truth or feeling that remains unarticulated due to our limitations.
This unspoken thing is related to a truth that "had not been spoken, which we had not even thought of speaking," and it is only in silence that this truth can be perceived. [5] The passages suggest that when we attempt to communicate profound matters like love, death, or destiny, our words fail to touch the real essence, and a truth that has not been spoken remains. [5] This unspoken truth, though voiceless, is what truly lives with us and absorbs us. [5]
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
oud that falls around them at the moment when men seem on the point of touching them, or when hurt has been done them. Some days there are when they seem to be of us, and among us, but a sudden evening comes and they are so far away that we dare not look at them, or ask a question. It is as though they were on life’s further shore, and the feeling rushes in upon us that now, at last, the hour has come for affirming that which is graver, deeper, more human, more real than friendship, pity or love; for saying the thing that is piteously flapping its wings at the back of our throat, and…
* * IT is idle to think that, by means of words, any real communication can ever pass from one man to another. The lips or the tongue may represent the soul, even as a cipher or a number may represent a picture of Memling; but from the moment that we have _something to say to each other_, we are _compelled_ to hold our peace: and if at such times we do not listen to the urgent commands of silence, invisible though they be, we shall have suffered an eternal loss that all the treasures of human wisdom cannot make good; for we shall have let slip the opportunity of listening to…
e wish to know, but it is hidden far above the secret thought—it is our secret silence. But all questions are useless. When our spirit is alarmed, its own agitation becomes a barrier to the second life that lives in this secret; and, would we know what it is that lies hidden there, we must cultivate silence among ourselves, for it is then only that for one instant the eternal flowers unfold their petals, the mysterious flowers whose form and colour are ever changing in harmony with the soul that is by their side. As gold and silver are weighed in pure water, so does the soul test its…
ently direct allusion has never yet been made, is the purest token of their eternal life. Whence it comes we know not. It is there in its simplicity, smiling on the threshold of our soul; and those in whom its smiles lie deepest, or shine forth most frequently, may make us suffer day and night and they will, yet shall it be beyond our power to cease to love them.... It is not of this world, and still are there few agitations of ours in which it takes not part. It cares not to reveal itself even in look or tear. Nay, it seeks concealment, for reasons one cannot divine. It is as though…
perhaps, more than others—that words can never express the real, special relationship that exists between two beings. Were I to speak to you at this moment of the gravest things of all—of love, death or destiny—it is not love, death or destiny that I should touch; and, my efforts notwithstanding, there would always remain between us a truth which had not been spoken, which we had not even thought of speaking; and yet it is this truth only, voiceless though it has been, which will have lived with us for an instant, and by which we shall have been wholly absorbed. For that truth was…