Quote:
Originally Posted by thedoc
Quote:
Originally Posted by peacegirl
None of this proves that what we are seeing is just a representation.
A photoreceptor cell is a specialized type of neuron found in the retina that is capable of phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential.
There are currently three known types of photoreceptor cells in mammalian eyes: rods, cones, and photosensitive retinal ganglion cells. The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form a representation of the visual world, sight. The rods are narrower than the cones and distributed differently across the retina, but the chemical process in each that supports phototransduction is similar.[1] A third class of photoreceptor cells was discovered during the 1990s:[2] the photosensitive ganglion cells. These cells do not contribute to sight directly, but are thought to support circadian rhythms and pupillary reflex.
There are major functional differences between the rods and cones. Rods are extremely sensitive, and can be triggered by a single photon.[3][4] At very low light levels, visual experience is based solely on the rod signal. This explains why colors cannot be seen at low light levels: only one type of photoreceptor cell is active.
Photoreceptor cell - Wikipedia, the free encyclopedia
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You are correct, this doesn't prove anything, but it indicates that the retina is composed of photosensitive afferent nerve endings that send signals to the brain to be interpreted as images, and signals to the brain and then to other parts of the eye to adjust the lens and the iris. After all this, Viola we see.
Rather than "something else is going on", with the brain looking through the eyes, and then "magic happens", and Viola we see.
Of course the 2nd scenario is much more romantic and poetic, and I can understand how Lessans would be fooled into believing it, lacking the relevant education. But I don't understand that you, supposedly with better education, can still believe it? |
A better education? What the hell are you blathering about now? There is no magic here. Signals are still going to the brain via the other senses. Signals are also being sent to the brain via the optic nerve. But this doesn't prove that the brain is interpreting these signals as virtual images representing real life.