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Sophie Rand

Student Engineering, The Cooper Union For The Advancement of Science and Art

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Can we ever know how another person "senses" the world?

In my Bioelectricity class this week, we learned about the cells
in our body that help us sense our environment: chemosensors in our
tongue that help us sense taste, for example, the photoreceptors in
our eye that sense light, and the hair cells in our ears that sense
the mechanical vibrations of sound, to name a few.

As a result, I recently revisited my answer to the age-old question of
“how do I know that the blue I see is the same blue you see?” that was
so startling and exciting to most 3rd graders playing baby Kierkegaard
a little bit differently. An answer could be that we just have to
trust that perception is guided by biology and that humans are
biologically identical to within 80% of our biological systems.

This answer, of course, raises new questions: even if you and I may
perceive the same blue, is that blue "real?" Where does sensation
leave off and perception begin, and how may we trust ourselves as we
try to compare them? Can we ever know how another person "senses" the
world? Would love to hear your thoughts!

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  • Feb 21 2012: It ought to be trivial to observe that we can only conceive of how others perceive the world in terms of how we perceive it. When an organism has more limited perception than we ourselves do do we feel confident that we can understand that organism's perception. For example, people with good color vision can effectively experience what it is like to see in black and white etc. When faced with types of perception we lack or have poorly we translate it IN TERMS OF OUR OWN PERCEPTION. For example, we have a poor sense of sonar that we complement with vision to imagine how a bat 'sees' the world; we imagine ultra-violet vision in terms of our light vision.

    The age-old question of “how do I know that the blue I see is the same blue you see?”contains a flaw. In general we answer the question "Do person A and person B see the same X?" in terms of the real world, and we will use real indicators to verify that they do indeed see the same X. There is no such X as blue. X may be a blue flower and in such a case we may verify that both A and B see a blue flower. Person A can imagine in terms of its perception what B sees and B can imagine in terms of its perception what A sees and we conceive of the whole scenario in terms of our own perception.

    The problem is not specifically a color problem. A completely color blind person could wonder if another such person sees the way they do. It is more easily expressed as a color problem because of the color wheel (that is a product of our mechanism of vision).

    Our method of answering such questions is through the analysis of mechanism. The extreme cases are:
    I see a blue object now in the way I see a blue object now - because the input and mechanisms are identical.
    No one sees the blue object in complete darkness - there is no mechanism .

    So we assert that similar inputs and mechanisms are a similar kind of perception. And if color wheel translation occurs we would expect it to evident in the mechanism.

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