Page 162 - Allah is Known through Reason

Nevertheless, even the subtlest sounds are perceived in the brain. This
is so precise that the ear of a healthy person hears everything without any
atmospheric noise or interference. In your brain, which is insulated from
sound, you listen to the symphonies of an orchestra, hear all the noises of
a crowded place, and perceive all the sounds within a wide frequency
range, from the rustling of a leaf to the roar of a jet plane. However, if the
sound level in your brain were to be measured by a sensitive device at that
moment, it would be seen that a complete silence is prevailing there.
Our perception of odour is formed in a similar way. Volatile molecules
emitted by things such as vanilla or a rose reach the receptors in the deli-
cate hairs in the epithelium region of the nose and become involved in an
interaction. This interaction is transmitted to the brain as electrical signals
and perceived as smell. Everything that we smell, be it pleasant or unpleas-
ant, is nothing but the brain's perception of the interactions of volatile mol-
ecules after they have been transformed into electrical signals. You per-
ceive the scent of a perfume, a flower, a food that you like, the sea, or
other odours you like or dislike, in your brain. The molecules themselves
never reach the brain. Just as with sound and vision, what reach your brain
simply electrical signals. In other words, all the odours that you have
assumed – since you were born – to belong to external objects are just
electrical signals that you feel through your sense organs.
Similarly, there are four different types of chemical receptors in the
front part of a human's tongue. These pertain to the four tastes: salty,
sweet, sour, and bitter. Our taste receptors transform these perceptions into
electrical signals through a chain of chemical processes and transmit them
to the brain. These signals are perceived as taste by the brain. The taste
you experience when you eat a chocolate bar or a fruit that you like is the
interpretation of electrical signals by the brain. You can never reach the
object in the external world; you can never see, smell or taste the choco-
late itself. For instance, if the taste nerves that travel to the brain are cut,
the taste of things you eat will not reach your brain; you will completely
lose your sense of taste.
At this point, we come across another fact: We can never be sure that

162 Allah is Known Through Reason