This visual sensation of vibration is a purely subjective one, the external cause of the phenomenon is the sound.

The outer world is a concert of sounds which rises in the immensity of space.
Matter is noise and nothingness is silence." This theory of the above experiment is not absurd; but, as a matter of fact, it is probable that no one would or could accept it, except verbally for amusement, as a challenge, or for the pleasure of talking metaphysics.

The reason is that all our evolution, for causes which would take too long to detail, has established the hegemony of certain of our senses over the others.

We have, above all, become visual and manual beings.

It is the eye and the hand which give us the perceptions of the outer world of which we almost exclusively make use in our sciences; and we are now almost incapable of representing to ourselves the foundation of phenomena otherwise than by means of these organs.