It is often said of cognitive scientists that we have, as a group, a memory that only stretches back about 10 years. This is for good reasons and bad. Methods change and improve constantly, constantly making much of the literature irrelevant. Then there is the fact that there is so much new work, it’s hard to find time to read the old.
This is a shame, because some of the really old work is impressive for its prescience. A recent issue of Trends in Neurosciences carried an article on Galileo’s work on perception. Most people then — and probably most people now — conceived of the senses as passing along an accurate representation of the world to your brain. We now know the senses are plagued by illusions (many of them actually adaptive).
Galileo was on to this fact. His study of the moon proved that perceptions of brightness are constantly subject to illusion. More generally, he noted — contrary to the popular view — that much of what we sense about the world is in a real sense an illusion. Objects exist, but colors and tastes in an important sense do not. It’s worth presenting a few of the quotes from the article:
I say that, as soon as I conceive of a piece of matter, or a corporeal substance,…I do not feel my mind forced to conceive it as necessarily accompanied by such states as being white or red, bitter or sweet, noisy or quiet, or having a nice or nasty smell. On the contrary, if we were not guided by our senses, thinking or imagining would probably never arrive at them by themselves. This is why I think that, as far as concerns the object in which these tastes, smells, colours, etc., appear to reside, they are nothing other than mere names, and they have their location only in the sentient body. Consequently, if the living being were removed, all these qualities would disappear and be annihilated.
see also:
A wine’s good taste does not belong to the objective determinations of the wine and hence of an object, even of an object considered as appearance, but belongs to the special character of the sense in the subject who is enjoying this taste. Colours are not properties of bodies to the inuition of which they attach, but are also only modifications of the sense of sight, which is affected in a certain manner by light.
Marco Piccolino, Nicholas J. Wade (2008). Galileo Galilei’s vision of the senses Trends in Neurosciences, 31 (11)
Re previous post: “The color red is real. As real as a meter. We can all agree to call light of wavelength 685 nanometers, red. After we agree, each person’s experience of 685 nanometer wavelength light will always be red.”
My first question is, if a ‘meter’ stick were travelling at a very fast speed and you were not, what length would that meter appear to take?
Our world is what we each, individually, perceive it to be. Sure we have ‘defined’ red to be EMR of wavelength 365nm, but since when have eyes been precision instruments that can determine that the wavelength we see is exactly 365nm? Impossible.
Our perception is ultimately influenced by many factors, some easily recognisable and some not so. For example, have you ever looked at the sky in a major city at night? You might assume that there is only a few bright starts out. But I would put millions of dollars on the fact that if you were to turn the city lights off, the sky would be filled with more bright specs than first thought. In both circumstances, the same number of stars litter the sky – only your perception changes. As you can see, the environment is just one of many factors that can influence (individual) perception.
What you are arguing is that once people agree on some physical characteristic of a corporeal body, that everyone will have the same experience of that substance from that time on? (!) Not everyone likes brussle sprouts!
These were both interesting points, but both somewhat tangential to the point I (and Galileo) was getting at. I can use spectroscopy to find out the wavelengths of light emitted by a particular object. But having that information is a very different experience from looking at an object and seeing that it is red.
Light exists, and it has wavelengths. The quality of light that we experience as red — that exists, as best we can tell, only in our minds.
Please try my web-based experiments
The color red is real. As real as a meter. We can all agree to call light of wavelength 685 nanometers, red. After we agree, each person’s experience of 685 nanometer wavelength light will always be red.
I think that was the point…
Yes – we have defined “red” as being 685 nanometers, but your second statement doesn’t always follow.
Color blind people, people with synesthesia, people with night vision goggles… They all might perceive red differently. Because their experience with light at a wavelenght of 685 nanometers is different than yours you cannot say it will always be red. It might, in fact, be blue to them.
The point is that everything we do via these senses is in some way filtered, managed and in some cases even obscured by the very detectors and delivery mechanisms in our own bodies.
Quote “they are nothing other than mere names, and they have their location only in the sentient body … if the living being were removed, all these qualities would disappear and be annihilated.”
Yes, I believe I see the point that you (and Galileo) were getting at. I guess my response to the previous post was not well communicated!
What I was endeavouring to explain (and obviously not too well) was that perception/interpretation such as taste, sight, sound, smell, etc only exist in our minds. If we weren’t capable of sensation and cognitive interpretation it is strongly arguable that these physical characteristics of the object do not exist.
Thus, because it possibly exists only in the mind, it is falliable to outside (and internal!) influences – illusions.
I am not a scientist, and I can only comment on my own experiences…
But I believe that my point of view coincides. (?) Please correct me if I am mistaken.
Here’s some of my own views on the topic… (and yes this is a little ‘tangential’):
There appears to be two requirements for me to determine the true existence of a corporeal object. Firstly, I must have the ability to perceive the object via my senses. If I cannot sense an object, this does not exclude an object from being ‘real’ or ‘existing’. For example, if someone presents me with a box just because I can’t see inside the box does not preclude something from being in the box. (Although my mind can convince me of either reality).
The other requirement, I believe, needed to deem whether an object is real is it’s perception by more than one living entity. This omits the possibility that the object is purely a figment of my imagination. For, in my perspective, if something is perceived by many then there must either be some ‘substance’ to the idea of it’s ‘reality’ or existence beyond one’s mind, or that somehow life has some kind of ‘linked’ cognitive ability – sharing of experience. The later sounds much less desiarable/possible/explainable but it cannot be excluded based on the original argument. i.e. just because we cannot perceive a ‘linked’ cognitive ability it does not mean that it doesn’t exist.
So an object may only exist if it is perceived. Therefore, perception and reality are delicately intertwined, and I don’t think we can ever determine if one can occur without the other, nor which one causes the other (if indeed they are a cause-effect pair).
Back to the same argument – did the egg or the chicken come first?
Ok, so I am a little crazy and mostly mislead.
Objects exist even when not percieved.
Our universe existed for 14 billion years prior to any human perception of it. Perception of an object does not cause that object to be. Quite contrary. Existance is what enables perception.
If your last sentence is saying that we must first exist, to be able to perceive… That is a given. But we only believe the universe existed for 14 billion years, because right now (in the present) we observe books that tell us so, read instruments that tell us so, and recall memories that tell us this is the case. This is perception; the observation of evidence and then cognitively processing this evidence to affirm ‘knowledge’ and then deem this ‘knowledge’ to be ‘truth’. Thus the universe existed prior to human inhabitance because we perceive it to have existed long before us!
If we didn’t have sight, hearing, touch, memory, etc then, to us, the universe would not have existed at any moment in ‘time’. (And nor would have we
)
This is getting very off track from the original piece!
If people with synesthesia are taught that the experience of 685 nanometers goes by the name of “red”, and they want to communicate effectively with others they will call it “red” too.
Check out this page: http://www.lottolab.org/articles/illusionsoflight.asp especially the leftmost item in the “Colour Illusions” section. The squares that appear to be blue on the left side are actually gray; and the “yellow” squares on the right side are also actually gray.
So, the light being emitted by your monitor is gray, but it appears either “blue” or “yellow” based upon the context.
It’s a perfect example of how non-absolute perception really is.
Do searches for “chromatic adaptation” or “colo[u]r illusions” for more examples.
When we incorrectly perceive a colour (or anything else). It is us, our eyes, our minds that are being wrong, not the colour itself being wrong. And we can not be ‘wrong‘ if there is no ‘right‘ to begin with.
The term illusion is defined as something that deceives by producing a false or misleading impression of reality. By definition, illusion only proofs the existence of a reality.
Let’s put it in a more logical sense. I’m going to the term “disappear” here but you can substitute with other similar terms such as “is deceived” or “varies”
- Premise)- We can only perceives objects through our(We's) neurosystem.
What happens if We disappears?
- Conclusion 1)- If We disappears ->
- our neurosystem disappears ->
- objects also disappears
Conclusion 1 does not hold. The correct answer is
- Conclusion 2)- If We disappears ->
- our neurosystem disappears ->
- our perception of objects also disappears
Note that Galileo got it right, he saidthese qualities would disappear ie tastes, smells, colours, not the object itself.
However, from Premise) + Conclusion 2), we get:
- Conclusion 3)- Our neurosystem cannot distinguish the difference between 'object disappear' and 'perception of object disappear'
Note that even if we cannot tell the difference, it still matters because there is always a possibility that a third party who is not bound by neurosystem or even perception exists. eg. alien? God?