My friend and I love one another. But that is not quite the right word. We rarely, if ever, speak about how we feel about each other. There have been moments, of course, when we have attempted to do so. I recall us once reminiscing about our first encounter, about how natural it had seemed, as though we had always known one another. Then, after the pause that followed, I suggested that perhaps some people one meets and others one recognises, which pleased him, but only a little. He had his own attempts at talking about our friendship, too. And each made me feel as I am sure mine made him feel: held in place, strangely cautious, a little uncomfortable.

Notwithstanding the fact that I am a writer and words are my business, it seems so plain to me that it is not in words that our most eloquent moments are to be found. Silence still has the upper hand. It is when nothing is said and my friend and I are, for example, walking side by side, that I can best detect something of the true nature of his regard. I don’t mean its description: the various emotions our relationship contains, the things and ideas and modes of being it makes possible when we are together. Language can report that.

But it is more that in silence the elemental shapes of those things seem to rise to the surface. The way I feel about my friends, my family, the woman I love can never be put perfectly in words because words are a translation. In silence, we are in the stage before translation. And we perceive it. And this strange wordless eloquence of ours is amazing to me. It makes me hopeful about our mutual susceptibility to the truth, and our shared nature, which allows us at times to understand one another, to gain an accurate approximation (for it will always be that, an approximation) of one another’s deepest emotions without even uttering a word. Put simply, I have hope in the unsaid. I don’t of course mean those malicious occasions where voices are silenced, but that other, telling silence, which is our universal language, and which has the genius of making even our most private of adjustments perceptible.

That silence is the deep, resonant well echoing the human spirit’s truest utterances, and not only with regard to our private relations but also our social and political dramas. Listen for it, slipping the truth in through the cracks in the speeches of our politicians, in the stillness of the room once everyone has left. Next time you are at a work meeting, or with someone you love, or standing in front of a painting, or reading a book, or cooking a meal, try to hear it. The more you attend to it, the more it will yield. It will tell you a great many things. Not all of them, of course, you would want to hear. And thinking this, I picture a mischievous historian in the hereafter – that is, if there will be a hereafter and one with historians in it – looking back from that great distance, after all has been said and done. She might conclude that the entire history of literature, across time and in all of our human languages, is but a noble human failure, our beautiful and heroic attempt to say something more lucid than silence. But she would also know that we had to speak and we had to write – as she herself must continue to do, even in the hereafter – and that our talk and literature have always been aided by that deep and resonant well. And she might conclude then that silence has always been on our side.

• A Month in Siena by Hisham Matar is published by Viking (£12.99). To order a copy go to guardianbookshop.com. Free UK p&p over £15