Page 92 - Darwin's Dilemma: The Soul

Darwin’s Dilemma: The Soul

When we imagine the book in our mind’s eye, we have an
experience very similar to when we actually see the book with
our physical eyes. This is an important proof that we can obtain an
image of an object in the brain only by thinking about it—an object
that does not really exist. The Washington University psychologist
Michael Posner and neurologist Marcus Raichle say this about the
brain’s extraordinary mechanism:

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 the scene you see with
your eyes, but still one that captures the scene’s essential character-
istics. 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? 57
What creates an object in our minds, in the absence of the orig-
inal of that object, is the same mechanism that creates it in our
minds when we imagine the original does exist. Therefore, the ex-
istence of the images we see as the external world is merely an il-

90