Walking at twilight when I spot a flock of large white birds flying low against the darkening sky. It is in a perfect formation and flying directly towards me. I brace myself, struck by the contrast of slow white motion and unmoving dark sky, and by the utter silence. In a moment, the flock is winging right over me. The sound is utterly unexpected: a low quiet hush, like a subtle wave over sand. A tangible tingle passes through me. Everything lasts a second. I look back to see the birds wing away.

As a child, the Indian mystic Ramakrishna one day fell into a swoon while crossing a field and seeing a flock of white birds against a dark sky. I could understand the experience when I read his biography (by the French writer Romain Rolland), but could not appreciate it as fully as I could the other day, and do now.