Page 66 - Darwin's Dilemma: The Soul

Darwin’s Dilemma: The Soul

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A Are Colors Only in Our Brains?
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What we perceive as light consists solely of signals interpret-
ed in our visual cortex. Therefore, colors, which stem from light
and pervade our entire lives, are nothing more than interpretations
by the brain.
The names of different colors are assigned to pho-
tons of various frequencies. We are able to distinguish
colors such as red and yellow according to the degree of
photon vibration: Thus different colors have different
scales of vibration. Paper and snow appear white be-
cause they reflect all frequencies, and the combination of
these gives rise to white. Leaves are green, because they re-
flect only photons at a frequency that gives rise to the ap-
pearance of green, while they absorb all the others. Glass is
transparent, because photons can pass through it and reach
our eyes without encountering any obstruction. A black fabric re-
flects very little light back because it absorbs almost all the photons
that strike it. As a result, few photons reach our
eyes, and we perceive the fabric as dark or
black.
A mirror copies an image be-
cause it has a smooth reflective sur-
face, and the moment that light rays

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