Why do we have 2 eyes? One eye is enough?
610977
You need to have two eyes to determine distance.  Basically, if you close one eye, you can still see, but when light hits your retina, it's all in a single plane, so even though your brain tries to add depth, it's basically getting a flat image.  But with two eyes next to each other, you can tell how far away something is based on how much is location relative to other objects changes in the information you're getting from each eye.  If something is further away, the distance between your eyes isn't going to make much of a difference to it's location on the retina, but if it's closer up, it's going to make a lot more difference.  The brain uses the information it gets about these differences to determine how far away an object is.  If you only had one eye, you'd be able to see objects, but you wouldn't know where they were, so you'd bump into walls all the time!
183620
+\nReal\n\nNo one really believes that the human eye developed from some other biological structure in one single generation, \nNo one believes the iris could have developed without a cornea, or a retina without a lens, or a pupil without an eyelid to protect it.\n\nEvolution of complex organs can’t occur in a single generation,  parts of organs cannot  evolve without the other parts. That is demanded by the concept of the survival of the fittest. Part of an eye gives no competitive advantage to one over another.\n\nEvolution of a specie is impossible!\n\nThe nest possibility is chance….   One day a man happened   without cause…..\nNot very likely\n\nThe last alternative possibility is that the spiecie migrated here from some other point in space or some other dimension.\nThat would still leave us with the question were they created…  and the same choices..\n\nYes creationism is real and the only logical possibility\nthere are many good resources
514687
All mammals are set up on a bilateral plan. Two arms, two legs, two eyes, two ears, two nostrils, two halves of the mouth and ideally are identical on either side. It has to do with the way the cells divide. So, humans would have to have an even number of nipples to maintain this symmetry.
413173
Our eyes are the exact same size since birth.
871539
Basically, Color, black and white are measured by the Cones and Rods in the back of you retinas.  And boy are there a lot of them.  But one eye might have a little more than the other eye  or there maybe more of them grouped in a certain location which may be the reason for the discreptancy.
1174351
Not really. The body can function quite well with just one. However, since they only have one left they have to be very careful not to damage it in any way.
30202
Ahh that is because the eyes can truly be the windows to the soul :o)
371380
Eye is a colage studint graduat. I must be pretty dumb if I answered this fuckin' question eh?
176213
Because it's a number that works. First, our bodies are symmetrical from left to right, so we're going to end up with an even number of digits, lest we be lopsided. We also are grabbers, being primates, and so we need an opposable thumb, and at least one finger for that thumb to oppose. One finger and thumb really aren't that great for grabbing though, and unless that one finger was really strong we'd be falling out of trees left and right. Several fingers add the support and versatility we need. Obviously, while adding more fingers we're going to reach a point where we have too many, where they become cumbersome. Considering the size of our hands in relation to our arms (giant Mickey Mouse hands would be unwieldy and look weird), it seems that four thin fingers and one thumb works out just fine. There are people and other animals who get by with fewer (and sometimes, more) digits. Looking across the animal kingdom, this 5 digit construction is rather common, though not every species has an opposable thumb. Even animals without digits per say, still have 5 similar bones where the digits would be (like bats). That doesn't really answer the core question of why we have them, but it answers why the number we have works so well.
103770
In the physical body the eye views objects upside down. It sends the image of what it observes to the brain which interprets the image and makes it appear right side-up to us.\n\nBut the human body has another physical eye whose function has long been recognized by humanity. It is called the 'Third Eye' which in reality is the Pineal Gland. It is long thought to have mystical powers. Many consider it the Spiritual Third Eye, our Inner Vision. \n\nIt is located in the geometric center of the brain. This correlates to the location of the Great Pyramid in the center of the physical planet.\n\nThe Pineal Gland is about the size of a pea, and is in the center of the brain in a tiny cave behind and above the pituitary gland which lies a little behind the root of the nose. It is located directly behind the eyes, attached to the third ventricle.\n\nThe true function of this mysterious gland has long been contemplated by philosophers and Spiritual Adepts. Ancient Greeks believed the pineal gland to be our connection to the Realms of Thought. Descartes called it the Seat of the Soul. This gland is activated by Light, and it controls the various biorhythms of the body. It works in harmony with the hypothalamus gland which directs the body's thirst, hunger, sexual desire and the biological clock that determines our aging process.\n\nWhen the pineal gland awakens one feels a pressure at the base of the brain. This pressure will often be experienced when connecting to higher frequency. A head injury can also activate the Third Eye - Pineal Gland.\n\nWhile the physiological function of the pineal gland has been unknown until recent times, mystical traditions and esoteric schools have long known this area in the middle of the brain to be the connecting link between the physical and spiritual worlds. Considered the most powerful and highest source of ethereal energy available to humans, the pineal gland has always been important in initiating supernatural powers. Development of psychic talents has been closely associated with this organ of higher vision.\n\nThere is a pathway from the retinas to the hypothalamus called the retinohypothalamic tract. It brings information about light and dark cycles to a region of the hypothalamus called the suprachiasmatic nucleus(SCN). From the SCN, nerve impulses travel via the pineal nerve (sympathetic nervous system) to the pineal gland. These impulses inhibit the production of melatonin. When these impulses stop (at night, when light no longer stimulates the hypothalamus), pineal inhibition ceases and melatonin is released. The pineal gland is therefore a photosensitive organ and an important timekeeper for the human body.\n\nRetinal research done with hamsters demonstrates another center for melatonin production. Located in the retina, this center implies that the eyes have their own built in circadian timepiece. This retinal system is distinct from the brains body clock in the suprachiasmatic nucleus (SCN). Biologists found that they could throw the retinal rhythms out of sync with other circadian cycles. They also found that they could set and reset the retinal clock even when the SCN was destroyed.\n\nThe retinal clock produces (stimulates the production of?) melatonin. Researchers are now looking for the exact location (s) of this clock in the human eye (and expect to find it). No one yet knows what the separate clock is for or how it relates to the SCN. \n\nIn some lower vertebrates the Epiphysis Cerebri - Pineal Gland - has a well-developed eye-like structure; in others though not organized as an eye, if functions as a light receptor. In lower vertebrates, the pineal gland has an eye like structure and it functions as a light receptor and is considered by some to be the evolutionary forerunner of the modern eye.\n\nThe gland weighs little more than 0.1 gram. The gland is large in children and begins to shrink with the onset of puberty. It appears to play a major role in sexual developmen
729207
Actually, we ARE living in a multi-demensional world. We just PERCEIVE 4 demensions (including time). Most people think that another demension is 'another place' where you have to 'go to' when in fact, all demensions are interposed and coexisting in the same space; you just dont SEE / perceive them. Very much like the Jinn...they are THERE although you don't SEE them cuz they're vibration is way too high for your eyes to perceive. For example, if you can see THROUGH a coffee mug for example or through people, you are PERCEIVING more demensions. In other words, the more demensions you can 'perceive' the MORE you can SEE...either way, they're all THERE. \nHope that helps.
1168850
lol  that's funny.  I would say blinking.\n\nBecause even with 2 eyes they both close at the same time.\nWhile winking you can see one of the other eyes is closed.  \n\nSince you cannot see another eye for whatever reason you see only one.  Thus you are blinking.
8890
There are other animals that have parietal  eyes.  These are fully functional eyes, and can account for 3 eys on lizards and other mamals; however the issue with these parietal eyes is that it is unknown how much one can see out of them because a scale/hair/skin grows over it.
339252
The areas in the brain that control the eye muscles send the signals to both eyes at the same time.  This is called muscle yoking.  It helps you look at objects at different distances and track objects that move across your vision.  The muscles in your hands/legs are activated separately from each other.
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My boyfriend who is blind in one eye says he does not gain the ability to see out of both eyes when he dreams. He thinks this is because he was born that way. He suggests that if a blind person was once sighted they will probably see in their dreams. However, if they were like him and born that way, they would not. He once explained it to me that seeing out of that one eye is as foreign to him as me seeing out of my finger.
235648
Because we only have two eyelids, silly!  Anything else would be wasteful.
95547
This all comes down to the way that vertebrates evolved, and it is a classic example of evolution producing a workable though complicated design that no intelligent designer would ever produce unless she were on drugs.\n\nTo explain let’s go back to the very earliest chordates. We are going back here to a time before our ancestors were fish, before they even had backbones. These things existed as essentially free-swimming worms a few inches long. No fins, no jaws, not even a real mouth, no limbs of any sort, just a body and a head. Every body segment aside form the head was identical and had just 4 muscle blocks. \n\nThese things lived by swimming around in the water filtering plankton from the water through a hole in their front end. That hole wasn’t a mouth, it was just a hole lined with beating hairs that drew in water.\n\nWith such a simple body plan these creatures didn’t require much nervous control by the ‘brain’ to the body.  Each body segment was controlled by a simple reflex arc from those 4 muscle blocks to the spinal cord. The brain could make them more or less responsive to stimulation and so cause the animal to turn left or right, but direct control from the brain to the body was extremely limited and there were correspondingly few nerves running from the brain to the body.\n\nWhat I haven’t mentioned is that this creature had EYES, and therein lies the reason for the crossing over. The early chordate brain was excessively devoted to operating some rather complex eyes that allowed it to see both  food and predators. So why are the eyes so important? Because when light enters they eyes it… crosses over. It inverts. You can follow the link below to get a better idea of this, with diagrams. But for now simply remember that the eye has a lense, and a lense inverts an image left to right as well as up and down. So with a brain devoted to processing inverted images collected through a lense it makes sense for the left brain to control the right body.  After all the information that comes from the left eye will in large part be telling the brain about conditions on the right side of the body.\n\n And so that is exactly what happened. These earliest chordates had (and still have) a brain with massive visual centres and limited  control of the body itself but, and this is vital, the left visual centres are largely located in the right brain. To move towards food on the left side of the body for example the signal form the left eye is processed by the right brain, and the right brain then sends the appropriate signals to the left body. To move towards visually acquired stimuli the signal has to cross over from the side of the brain that processed the data to the OPPOSITE side of the body.\n\nAs chordates became larger and more complex one of the things they did was to grow paired fins. They ceased being wormlike and became fishlike. But paired limbs require far more fine and centralised control than can be provided by a reflex arc to the spinal cord. So the brain assumed control. \n\nThe same brain that had evolved a complex crossover so that visual data corresponded to the correct side of the body was now being asked to assume direct control of paired limbs. Of course evolution works with what it has, not with what is best. The brain had a complex crossover for controlling the muscles of the body, and it couldn’t re-wire that, so it simply built on it. Limb control also crossed over form the left to the right brain even though it was no longer under visual control.\n\nAnd as we became more and more complex we simply kept the same convoluted design. The reason the left brain control the right arm today is simply because hundreds of years ago information form the left eye was processed by the right brain, which was a very sensible solution at the time.