Sense of hearing

Scientific Perspective

All sound is vibration, and vibrations can travel through gases, liquids, and solids. Air pressure is the air molecular density, and sound waves are variations in air pressure over time. The frequency of the sound wave is related to the pitch, and the amplitude determines the loudness. Sound waves that we hear have complex waveforms composed of a combination of frequencies.

Sound waves entering the ear, cause the ear drum to vibrate, which in turn causes the bony ossicles to vibrate, which in turn causes the oval window to vibrate, which in turn causes the fluid and membranes within the cochlea to vibrate, which in turn causes the hair cells and the hairs upon these cells to bend. The molecular cables connected to the hair cells are only 3 nanometers in diameter, and are coupled to potasium ion channels. Hair cells at different locations with the cochlea respond to different frequencies of vibration. There are approximately 3,500 inner hair cells, and 12,000 outer hair cells per cochlea.

The bending of these hairs initiates electro-chemical signals which travel along the auditory nerve into the brainstem. Neural signals are processed by several regions of the brainstem and auditory cortex, contributing to the experience of sound.

Buddhist Perspective

To hear the sound by ear consciousness three conditions must be fulfilled. Firstly, the objective condition which is the object (sound), secondly the dominant condition which is the ear sense faculty, and thirdly the immediately preceding condition.

Sound is produced by rubbing two objects together. The scientific concept of a sound wave is very similar to the Buddhist conclusion on the nature of sound, which is devoid of a homogenous continuum.

Sounds are categorized as subtler and grosser.  Some of the subtler sounds are imperceptible to human beings. However, all kinds of sound in the universe can be heard by a Buddha through their superfine sense faculty.

The dominant condition or the ear sense faculty is an invisible physical form which is made up of fine particles.  The main inner ear looks like a birch bark, caught up swirling on the inside.  The Buddhist claim of birch bark like ear sense faculty mentioned here may be identified as the term cochlea used in science.

The immediately preceding condition is the nature of our awakening consciousness, and it is devoid of shapes and colors.  Both the conceptual and non conceptual consciousness can cause the immediately preceding consciousness to the ear consciousness.

These three conditions cultivate ear consciousness in us for hearing the sound, and this consciousness later produces the mental consciousness which recalls ” I once have heard that particular sound”.

Last Updated on Saturday, 18 December 2010 04:52