Page 248 - For Men of Understanding

in surrounding space. From the patterns of simulation on the retinas we
perceive the world of objects, and this is nothing short of a miracle. 2
The same applies to all our other senses. Sound, touch, taste and smell are
all transmitted as electrical signals to the brain, where they are perceived in the
relevant centres.
The sense of hearing proceeds in the same manner. The auricle in the outer
ear picks up available sounds and directs them to the middle ear; the middle
ear transmits the sound vibrations to the inner ear by intensifying them; the
inner ear translates these vibrations into electrical signals and sends them to the
brain. Just as with the eye, the act of hearing takes place in the brain's hearing
centre. The brain is insulated from sound just as it is from light. Therefore, no
matter how noisy it may be outside, it is completely silent inside the brain.
Nevertheless, the brain perceives sounds most precisely, so that a healthy
person's ear hears everything without any atmospheric noise or interference.
Your brain is insulated from sound, yet you listen to the symphonies of an
orchestra, hear all the noises in a crowded auditorium, and perceive all sounds
within a wide frequency, from the rustling of leaves to the roar of a jet plane.
However, were a sensitive device to measure the sound level in your brain, it
would show complete silence prevailing there.
Our perception of odour forms in a similar way. Volatile molecules, emit-
ted by vanilla extract or a rose, reach receptors in the delicate hairs in the olfac-
tory epithelium and become involved in an interaction that is transmitted to the
brain as electrical signals and perceived as smell. Everything that you smell, be
it pleasant or repugnant, is only your brain's perception of the interactions of
volatile molecules transformed into electrical signals. The scent of a perfume,
a flower, any delicious food, the sea, or other odours you like or dislike, you
perceive entirely in your brain. The molecules themselves never reach there.
Just as with sound and vision, what reaches your sensory centres is simply an
assortment of electrical signals. In other words, all the sensations that, since
you were born, you've assumed to belong to external objects are just electrical
signals interpreted through your sense organs.
Similarly, at the front of your tongue, there are four different types of chem-
ical receptors that create the tastes of salty, sweet, sour, and bitter. After a series
of chemical processes, your taste receptors transform these perceptions into
electrical signals and transmit them to the brain, which perceives these signals

as flavours. The taste you get when you eat chocolate or a fruit that you like
is your brain's interpretation of electrical signals. You can never reach the
object outside; you can never see, smell or taste the chocolate itself. For
instance, if the nerves between your tongue and your brain are cut, no further

246 For Men of Understanding