Page 44 - Matter: The Other Name for Illusion

Michael Posner, a psychologist and Marcus Raichle, a neurologist from
Washington University comment on the issue of how sight and other senses
occur, even in the absence of an external stimulus:
Open your eyes, and a scene fills your view effortlessly; close your eyes
and think of that scene, and you can summon an image of it, certainly not
as vivid, solid, or complete as a scene you see with your eyes, but still one
that captures the scene's essential characteristics. In both cases, an image
of the scene is formed in the mind. The image formed from actual visual
experiences is called a "percept" to distinguish it from an imagined image.
The percept is formed as the result of light hitting the retina and sending
signals that are further processed in the brain. But how are we able to
create an image when no light is hitting the retina to send such
signals? 10

There is no need for an external source to form an image in your mind.
This same situation holds true for the sense of smell. In the same way as you
are aware of a smell which does not really exist in your dreams or imagination,
you cannot know about those objects, which you smell in real life, that exist

outside you. You can never deal with the original objects.

All Tastes Occur In The Brain

The sense of taste can be explained in a manner
similar to those of the other sense organs. Tasting is
caused by little buds in the tongue and throat. The
tongue can detect four different tastes, bitter, sour,
sweet and salty. Taste buds, after a chain of processes,
transform sensory information into electrical signals

and then transfer them to the brain. Subsequently,
those signals are perceived by the brain as tastes. The
taste that you experience when you eat a cake, yogurt,
a lemon or a fruit is, in reality, a process that
interprets electrical signals in the brain.
An image of a cake will be linked
with the taste of the sugar, all of

which occurs in the brain and
everything sensed is related
to the cake which you like so

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