We often seek silence for peace and tranquility, but can we ever truly experience it? Every sound we hear has a frequency within our hearing range, and even in the quietest place, there are always some reflections of sound waves. Even in an anechoic chamber, where there is no reflection of sound or electromagnetic waves, we still hear the sound of our own body - the nervous system and the heartbeat. Silence, therefore, is a relative concept. It's about focus and tuning out the constant sound vibrations around us. Even in the quietest place, we're never truly alone with silence - we always bring our own noise with us.

Vibrations are all around us always, and those with frequencies in our range of hearing are perceived as sound. Sound waves are around us constantly—we pick up on those in the general range 20-20,000 Hz. As we age, we lose perception of the upper frequency range.

Technology has made it possible for us to drown out the ambient sound with our choice of music or podcast. Being able to determine what is the most prominent sound around us might help us feel better or learn something, but it also dulls our openness to whatever is appearing, our mindfulness of the moment in which we find ourselves.

This awareness has led many to seek silence as a way of connecting with their inner selves, as a way to focus on being in the moment, as the best environment for meditation.

But do we ever truly experience silence?

The Greek philosopher and scientist Pythagoras believed that the motion of the stars and planets produced sound, which he called the “Music of the Spheres.” Pythagoras had discovered that when material vibrates, the larger or longer the vibration, the lower the frequency.  He is also reputed to have uncovered the proportions that create the signature overtones for acoustic sound: when a string or pipe – or any material generally – vibrates along its full length, it produces its fundamental pitch or frequency. But it is also vibrating in halves, producing an octave higher, in thirds, producing the interval above that, and in fourths, producing a second octave above the fundamental. These proportions govern sound vibrations, so Pythagoras concluded that similarly, the vibrations of the planets around us were creating sound, sound that we don’t perceive because it is always there, unchanging.

Pythagoras was right that there are many vibrations around us that we don’t perceive, but these are not created by distant astronomical bodies like the planets and the stars. We don’t experience frequencies outside of our hearing range, but there is always some reflection of sound waves that lie within this range, however soft. 

It is possible to create a space where there is no reflection of sound or electromagnetic waves. This is an anechoic chamber. Anechoic means “no reflections or echoes.” This would be the only possibility for us not to hear anything, truly to experience silence.  But even in an anechoic chamber you hear two sounds, both coming from within your own body: there is a high pitch produced by the nervous system and a lower pulsing sound that is the beating of the heart. So the ears are always receiving sound waves, if not from the external environment, then from within the body. 

Silence is thus a relative concept, and it pertains to focus; we hear something when we turn our attention to it. We are constantly tuning out sound vibrations that are around us. With the increased use of machines in our daily lives, there is much more ambient noise, and we tend only to notice something irregular in a steady sound pattern. Do you remember the music that was playing the last time you had a meal in a restaurant? You know there was music playing but you probably were more focused on conversation with a friend. But when a loud unexpected sound, the server dropping a tray of glasses for example, reaches our ears, it will steal our attention.

Silence is used in both speeches and music to call our attention to whatever comes next. An orator may suddenly interrupt her speech with a rhetorical question and silence, drawing your attention to what comes next. Similarly, silence in a musical work creates a sort of negative space, highlighting what comes next by drawing our attention to it.