RE: Berkeley's argument for the existence of God
March 29, 2018 at 5:29 pm
(This post was last modified: March 29, 2018 at 5:30 pm by polymath257.)
Light of an interval of wavelengths is called 'blue' because when we see such light, we get the experience of seeing blue. The same for red, yellow, green, etc.
The wavelength (equivalently, the frequency) is a property of light (along with direction of travel) which is directly related to the energy of the photons carrying that light.
We have the experience of blue light because in our eyes, there are pigmented cells that send signals to our brains when exposed to light. The specific pattern of signals is interpreted by our brains as color (as well as other things, like direction, etc). So, light with a certain range of wavelengths produces certain types of signals because it stimulated certain cones in our retinas. That sends signals through the optic nerve to the occipital region of the brain where it is interpreted as a color: the color blue.
Now, most times when we see things, the eyes respond to a variety of wavelengths at the same time, so we see a mixture via the signals sent to the brain. But it is possible for two different *physical* situations to give the same signals, so we see them as the same color. They can be distinguished physically by their electromagnetic properties, but we do not 'see' a difference.
This happens more dramatically for color blind people who lack one type of cone, so see the same color when most of us see different colors (specifics depend on the type of cone lost). In this sense, most mammals (such as dogs) are color blind: they only have two (or one) type of cone.
But certain birds have MORE than three types of cone, so they can distinguish colors that we cannot. The signals going to their brains carry information from four or more types of cone, so can distinguish physical situations that we cannot.
So it is essentially certain that there will be two 'colors' that we see as *absolutely the same (not just different shades) that a duck, for example, would see as different.
Light is a physical process. The experience of light is determined by what information gets transferred to our brains to be processed.
The wavelength (equivalently, the frequency) is a property of light (along with direction of travel) which is directly related to the energy of the photons carrying that light.
We have the experience of blue light because in our eyes, there are pigmented cells that send signals to our brains when exposed to light. The specific pattern of signals is interpreted by our brains as color (as well as other things, like direction, etc). So, light with a certain range of wavelengths produces certain types of signals because it stimulated certain cones in our retinas. That sends signals through the optic nerve to the occipital region of the brain where it is interpreted as a color: the color blue.
Now, most times when we see things, the eyes respond to a variety of wavelengths at the same time, so we see a mixture via the signals sent to the brain. But it is possible for two different *physical* situations to give the same signals, so we see them as the same color. They can be distinguished physically by their electromagnetic properties, but we do not 'see' a difference.
This happens more dramatically for color blind people who lack one type of cone, so see the same color when most of us see different colors (specifics depend on the type of cone lost). In this sense, most mammals (such as dogs) are color blind: they only have two (or one) type of cone.
But certain birds have MORE than three types of cone, so they can distinguish colors that we cannot. The signals going to their brains carry information from four or more types of cone, so can distinguish physical situations that we cannot.
So it is essentially certain that there will be two 'colors' that we see as *absolutely the same (not just different shades) that a duck, for example, would see as different.
Light is a physical process. The experience of light is determined by what information gets transferred to our brains to be processed.
