Ontmeta2. What is silence?

Two Fundamental Conceptions of Silence

There are two fundamental conceptions one can take toward the nature of silence that we will call absolute versus relative silences? An absolutist approach is all or nothing. There either exists a particular event or situation where there exists sound, which is a situation without silence, or there exists a complete lack of sound where silence exists. On the relativist approach complete lack of sound is unnecessary. All that is required for silence to exist is for there to be what for lack of a better standard we can call minimum sounds. Both of these conceptions are explored below

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Dictionary's Definitions for Silence

Dictionary.com defines silence as a noun relative to sound in two ways:

1. Absence of any sound or noise; stillness.

2. The state or fact of being silent; muteness.

It is important to notice that in the second definition silence is defined in terms of being silent.

What is the definition of “silent”?

Dictionary.com understands “silent” as an adjective with multiple meanings:

1. Making no sound; quiet; still: a silent motor.

2. Refraining from speech.

3. Speechless; mute.

4. Not inclined to speak; taciturn; reticent.

5. Characterized by absence of speech or sound: a silent prayer.

6. unspoken; tacit: a silent assent.

Notice that all of the definitions besides the first one concern themselves with speech and speaking. Thesaurus.com even has as a synonym for silent the word “speechless.”

Turning our attention back to the very first definition of silent as “making no sound” an obvious synonym for this meaning is “soundless.” Soundless presumably means the complete absence of sound. This would be an absolutist conception of silence.

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Problems for an Absolutist Conception of Silence

Can there ever be a complete absence of sound?

On the face of it, it appears that a complete absence of sound is impossible.

Why is a complete absence of sound impossible?

Surely there can be an absence of sound in the vacuum of outer space! The reason to believe this is that sound is the result of the vibration of molecules in some sort of media, such as air, water, or any type of matter itself. Since a vacuum is an absence of matter there is nothing to vibrate and hence no sounds are possible or so goes the thinking up to this point.

This view has been put forth at Northwestern University's website "Welcome to the Principles of Operation on "What's It Like in [Outer] Space?" where it addresses the question, “Is there sound in [the vacuum of outer] space?

“Sound travels in waves like light or heat does, but unlike them, sound travels by making molecules vibrate. So, in order for sound to travel, there has to be something with molecules for it to travel through. On Earth, sound travels to your ears by vibrating air molecules. In deep space, the large empty areas between stars and planets, there are no molecules to vibrate. There is no sound there.”

They use the graphic displayed below to show the contrast between an astronaut inside of a spaceship who can hear a thunk from outside, such as when his ship is struck by some space debris, while the astronaut outside the ship cannot hear such an impact sound because there is no medium within which any waves could travel to the space walking astronaut's ears. Hence, there is no sound in the vacuum of space that the astronaut can hear.

But this doesn't mean or require that there is nothing to be heard near the astronaut.

At the same website it is pointed out that there is energy and matter and kinetic energy of this matter in outer space.

“Is there energy in space? There is abundant energy in space. Even though most of deep space (the vast stretches of empty area between planets, stars and moons) is cold and dark, space is flooded constantly by electromagnetic energy. All stars in the universe produce energy and send it out into space. Planets, asteroids and moons reflect that energy back, glowing in the darkness. They can also release energy themselves in the form of heat from volcanoes or other processes. Virtually everything in space is in motion, so there is also kinetic or motion energy in space.

But is the vacuum of outer space entirely void of matter that could vibrate and therefore count as sound?

The answer is that the vacuum of space is not entirely voided of matter. Photons, cosmic radiation, virtual particles popping in and out of existence spontaneously. Energy is matter equivalent because of e = mc²

The status of virtual particles and the best way to conceptualze them remains somewhat fluid out on the Internet. Physicist Matt Strassler has a good discussion about some of the relevant issues at his website.

After some extensive research it was found that at least one source asserts that virtual particles can have mass. This still needs to be tempered by the kinds of considerations raised by Matt Strassler and others.

“Virtual particles do have mass, even when they are part of massless forms, such as photons.”

Theoretical physicist Matt Strassler explains that virtual particles are misnamed. They are not particles in the sense of stable, that is unvarying objects, with stable property values. Instead it is a less naive view to conceive of virtual particles as "general disturbances" within a field (electron field, electromagnetic field, etc.).

“Virtual particles, which are what appear in the loop in that diagram, are not particles. They are not nice ripples, but more general disturbances. And only particles have the expected relation between their energy, momentum and mass; the more general disturbances do not satisfy these relations. So your intuition is simply misled by misreading the diagram. Instead, one has to do a real computation of the effect of these disturbances. In the case of the photon, it turns out the effect of this process on the photon mass is exactly zero.”

“In formal terms, a particle is considered to be an eigenstate of the particle number operator a†a, where a is the particle annihilation operator and a† the particle creation operator (sometimes collectively called ladder operators). In many cases, the particle number operator does not commute with the Hamiltonian for the system. This implies the number of particles in an area of space is not a well-defined quantity but, like other quantum observables, is represented by a probability distribution. Since these particles do not have a permanent existence, they are called virtual particles or vacuum fluctuations of vacuum energy. In a certain sense, they can be understood to be a manifestation of the time-energy uncertainty principle in a vacuum.” (bold not in original)

If there is any matter then where that matter exists waves can be generated that travel through the matter that vibrate the matter. This counts as sound generation whether it can be heard by human hearing or not.

One must admit it would be pretty quiet in outer space, but any human organism can likely hear their own heart beating and blood rushing through their ears when inside of a space suit similar probably to John Cage's experience of hearing just these things when he entered an anechoic sound proof chamber at Harvard.

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The Advantages of a Relativist Conception of Silence

The two conceptions of silence have different problems. The absolutist has the problem of how to discover in any relevant situation that no sounds exist at all, even extremely quiet sounds would shatter the existence of silence. Just because one's current machine detects no sounds does not mean there are none. On an absolutist conception, how can it ever be known no sounds exist at all, which must be known to know silence exists.

The relativist conception of silence has the problem of determining what sounds are acceptable during the existence of silence. On this view, sounds and noises can exist during silence, but by what standards is the minimum condition of dearth of sounds determined? How quiet is quiet before silence exists?

Silence Can Exist Depending Upon How It's Defined

Rather than defining silence as the complete lack of sound, one can qualify something as silent when particular conventions and behaviors are followed, or if there are minimal sounds to a certain standard of acceptable sounds for silence to be maintained.

Wikipedia on Silence notes that there are standards such that when they are met qualifies the situation for having achieved (relative) silence.

“Silence is the lack of audible sound or presence of sounds of very low intensity. By analogy, the word "silence" can also refer to any absence of communication or hearing, including in media other than speech and music. Silence is also used as total communication, in reference to nonverbal communication and spiritual connection [clarification needed]. Silence also refers to no sounds uttered by anybody in a room or area.”

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Can Silence Exist?

• Can silence exist?

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