It is an accepted fact that the musical sound pleases while noise displeases the ear and the mind of a person. The difference between the musical sound and the noise is that the former arises from a regular vibration of an object in air and the latter from an irregular vibration. A person listening to pleasing musical sound does so because his feelings are agreeable to that sound. It is not so in the case of a noise. The sensation of pleasing is caused by the regular vibrations. In other words, we may say that the cause for agreeability is regularity.
Regularity is the order of nature. Regularity applies to the movement of planets round the sun. All these planets move round their axes in regularity. The day, night, months, years, seasons pass in regularity. Birth, old age and death take place in regularity. Growth and development of all living things are governed by regularity. These observations go to confirm that adherence to regularity means pleasure and the opposite means pain.
From the study of embryology we come to know that the embryo in the mother’s womb gets a sensation of regularity through pulsation which is the most important discipline of regularity running through the lifetime of human being. Heart and pulse are interconnected and the whole body is drilled into the discipline of regularity. The nervous system is agreeable to regular impressions and disagreeable to irregular impressions. As a result, impacts of incidents cause convenience or inconvenience to the body and mind respectively. Accordingly, a sound originating from a regular vibration pleases the ear while those originating from an irregular vibration displeases it. In other words, musical sound pleases the ear but noise displeases.