flaws in sensory evidence

Metaphysics and Epistemology
1

I know that one of the cornerstones of Objectivist epistemology is the idea of empirical data. Keep in mind, that I have not read ITOE, when you answer my question.

How does Objectivism account for the fact that our senses are not perfect? Our senses have evolved very gradually and are sure to continue evolving. We have better vision than cats, which have better vision than insects, which have better vision than bacteria, but none of them are perfect. Surely, our senses will continue to evolve and get better over the aeons, but they do not give us a perfect representation of reality.

2

What do you mean by ‘perfect?’ If you mean that perfect sensation would give all possible information about the identity of an existent, what information could that be? Do you mean omnisensate (a word I made up to mean all-sensing)? Wouldn’t that be a violation of the identity axiom as applied to the senses, just like an omniscient consciousness would be?

Objectivist epistemology does not require ‘perfect’ sensation in the sense you suggest. It only requires that the information provided by sensation be somehow causally and automatically connected to reality. Some real information, not all.

-Q

3

The senses are flawless; how we interpret them and conceptualize from them can be flawed.

4

The only source of knowledge you have about the world is your senses. If you hold that your senses are accurate, then one has a means of knowing about the world, including such theories as the validity of the senses. But if you hold that your senses are not accurate, and that they are flawed or misleading, then one has no means of knowing about the world, no ability whatsoever to claim any theory as actual knowledge about the world, and therefore no reason whatsoever to say that the senses are flawed.

Claiming that the senses are flawed is self-contradictory, because you first have to accept the validity of the senses to be able to say that knowledge at all is possible, and you have to say that knowledge at all is possible in order to say certain specific knowledge about the senses, particularly that they are flawed.

The validity of the senses is an axiom (which ITOE validates). All knowledge, and in particular any verbal statement regarding the validity or invalidity of the senses, presupposes the validity of the senses.

5

The only source of knowledge you have about the world is your senses. If you hold that your senses are accurate , then one has a means of knowing about the world, including such theories as the validity of the senses. But if you hold that your senses are not accurate, and that they are flawed or misleading, then one has no means of knowing about the world, no ability whatsoever to claim any theory as actual knowledge about the world, and therefore no reason whatsoever to say that the senses are flawed.

(bold emphasis mine)

We have more than one way and more than one sense to examine an object, and therefor, even though our senses do give false information about the world sometimes, we still have a way to know that it is wrong, IF we keep in mind this fact, that our senses do not provide 100% accurate, reliable information at all times.

For example: the color of an object and the amount of illumination you perceive it as having are not it’s actual wavelength that reach your eye. What you perceive is a result of the actual color/brightness compared against the environment. However, if you are interested in knowing with 100% certainty if two objects have the same color, even though their surrounding is different, you can use a device that measures wavelength.

Here’s a site about optic illusions, in case you think I’m bluffing about our senses being misleading in some cases (though I doubt anyone here doesn’t already know this).

Likewise our eyes only sample the world at 50Hz (or thereabouts). If there is a visual signal that changes faster than that, we will not be aware of it. Problem? not necessarily. We have devices that record light faster than 50Hz.

So can you please define what you mean by “validity” in: “The validity of the senses is an axiom”?

6

How does Objectivism account for the fact that our senses are not perfect?

I don’t recall Rand saying anything like “The senses are perfect”. The idea of reducing higher-level knowledge to the axiomatic (sensations) doesn’t license improper inference. So when I make a bad guess about the color of an object, it’s because it’s a guess.

7

I totally forgot about this thread. At any rate, my question has been answered, but I don’t think I can contribute anymore to the subject until I’ve read ITOE. Just wanted a brief explanation.

8

I’ll quote from the Ayn Rand Lexicon under “Perception” , which is in turn a quote from Galt’s speech:

[Man’s]senses do not provide him with automatic knowledge in separate snatches independent of context, but only with the material of knowledge, which his mind must learn to integrate… His senses cannot deceive him,… physical objects cannot act without causes,…his organs of perception are physical and have no volition, no power to invent or distort…the evidence they give him is an absolute, but his mind must learn to understand it, his mind must discover the nature, the causes, the full context of his sensory material, his mind must identify the things that he perceives.

So, what is clear is that she does regard the senses as infallible. The reason for this is because perceptual data is reality in some form. It can only be what it is, and not what it isn’t. I think Ayn Rand puts it this way “You can’t perceive reality as it isn’t.”

According to Objectivism, the only place that error is possible is on the conceptual level, where we have to integrate our knowledge via logic.

9

We have more than one way and more than one sense to examine an object, and therefor, even though our senses do give false information about the world sometimes, we still have a way to know that it is wrong, IF we keep in mind this fact, that our senses do not provide 100% accurate, reliable information at all times.

But Objectivism never claimed that sensory perception gives you direct information about the object; it gives you direct (infallible) information about the object’s relationship to your sense organs.

Take the example of the color blind man vs the man with normal vision. They might both look at the same object, and the color blind man will see it as grey, whereas the man with normal vision sees it as green. The intrinsicists or “naive realists” who thought perception gives direct knowledge of objects would have a difficult time explaining how this would be possible. But the Objectivist solution (as I understand it–Leonard Peikoff discusses this problem in his History of Western Philosophy lecture course) is that perception doesn’t give you knowledge about whether the object is “green” or “grey” in itself, but rather, “the nature of the object is such that when light reflected from the object in certain conditions reaches my eyes, I experience green,” or for the color blind person, the same but with grey. And both people will be correct in this assessment.

For example: the color of an object and the amount of illumination you perceive it as having are not it’s actual wavelength that reach your eye. What you perceive is a result of the actual color/brightness compared against the environment.

I’m not sure what you mean when you say “[its] actual wavelength,” because “wavelength” is not something that exists intrinsically in an object, but is the result of an interaction between the object and a light source, under certain conditions. If the conditions change, then the wavelength will change. I’m far from an expert on physics, but I’m pretty sure that the wavelength that reaches your eye when you perceive an object is the actual wavelength reflected from the object in the environment. Do you mean that the wavelength you actually perceive is not the same as the wavelength that reaches your eye? But people don’t perceive wavelengths.. They perceive the effects of wavelengths on their sensory apparatuses.

10

Bold Standard: I’m not sure I understand your claim about the meaning of “accurate knowledge”.

Our senses are a device. Now suppose some device measures temperature, and it has an error range of 1 degree (+/-).

Is that device “accurate”? I would say no, it has it’s limits. And our senses are just the same. We are still, however, able to trace down the inaccuracies because we can gain knowledge of something in different ways.

For example: the blind spot: If you look at an object from a certain distance, your brain will give you a WRONG image of that object (it will attempt to “complete the image”, by making you perceive something that is not actually there), but when you change the distance or change the location of your focus, then you can see another image. When you integrate your knowledge you realize that one of the images must be WRONG, and you run more tests to see which one is wrong, and why.

For me, this indicates that our senses are NOT accurate, and NOT infallible, but we are still able to gain accurate knowledge by the use of our mind, and understanding our limitations/sensory inaccuracies, which would be like learning to use a device in it’s range of accuracy, learning when a device is reliable.

As for what I said about wavelengths and perception: Even if the same wavelength from two objects reaches your eye, you might still perceive their color as different (significantly different, like blue instead of green).

The wavelength that reaches your eye is the result of the object’s properties and the illumination (light source).

Our eyes are not a photon-meter, and thus they do not give accurate knowledge about the wavelength reflected by the object.

11

Discussions of the validity of the senses often go astray in distinguishing ideas about sense organs and perception. The notion of “accurate” is by nature a conceptual one, which implies a standard of measurement. The eyes therefore cannot be accurate or inaccurate, since the eyes do not measure. Sense organs transduce an external physical signal into something that our perceptual apparatus can act on to create something cognitive in the brain, a percept. An eye is more like a microphone than a thermometer.

It is ridiculous to think that anybody says that the eyes perfectly transduce all facts about electro-magnetic energy that strike them, or that the ears present the mind with an infinitely precise representation of an acoustic wave in terms of time, frequency and amplitude. The eyes and ears do what they do, and they act in obedience to their physical nature, without thinking of clever ways to ruin your life; and that is the part that cannot be questioned. Your interpretation of what your sense organs present to you can be erroneous.

Errors are necessarily interpretative errors, where the mind fills in missing raw data or adjusts data, or are sometimes just social errors. An example of a social error in perception would be when a person from northern Ohio hears the word “pen” pronounced and thinks that the word uttered was “pin”, because of a social fact about the pronunciation standards in that region. Or, when I see an ostensively red-colored object under certain circumstances, it would be an interpretive error for me to say that that line was red – I know very well that it could be any one of a number of colors, and to claim that it is red is a mistake on my part. Of course, people do not always know the reason for their interpretive mistakes.

12

I believe I can bring a unique perspective into this conversation. I will tell you what I think, then I will give my real life justification on why I think what I think (I know this sentence sounds confusing, but please, read my entire post, then you would understand).

First, it is true that our senses can provide the brain with wrong data, which happens all the time. However, a rational person would be able to use his other senses to verify if one sense is giving him incorrect information.

A person who’s mind is in a rational state would realize that he (or she) would either require more information before making a judgement (e.g. merging lanes on a freeway, that’s why you need to look over your shoulder and look in the mirrors before merging) or realize that the brain is malfunctioning and the individual needs medical attention (e.g. if an individual sees a pink elephant).

How do I know this is to be true? Because in my life, I have experienced both of these phenomena in my brain. In the first case, I can “see” music and sounds. Different sounds produce different shades of colors depending on the instrument used, pitch, and “blending”. When I was younger, I used to describe to my friends how much I like a song because of the type of color it makes. I have since learned that most people do not have this ability and that music can not produce or change colors. So whenever I hear music, or hear something, I disregard the color that it makes (unless the colors - and music - gives me pleasure, in that case, I indulge myself in it). I have since taught myself that music is caused by vibrations of air, hitting my ear-drum, and the ear-drum “transporting and encoding” those sounds to my brain, and not some type of color producing event.

For the second type of phenomena that I experienced (hallucinating), that was done because of drugs. I was put on a pain killer which I found out later to be allergic. About 30 minutes of taking this drug, I noticed that my keyboard, and desk, felt smooth and cool like glass. Because my brain, at that time, was still functioning, I ignored the feelings because every other sense was telling me (correctly) that I was sitting at the desk, typing. Then, I started hearing things (I was hearing voices of people, but I couldn’t make out what they were saying). Because there was no one else in the room, I ignored those voices as well. As time passed, I started having a harder time remember things (remembering what I read 6 words ago became a very hard chore), and I started being “in places” that I never was in. At this point, It became a hard struggle for me to think of the words “Stop! Not real!” and went up the stairs to my friends room, who took me to the Hospital. The conclusion of this was my mind was “out of focus” and no longer functioning properly. Thankfully, I had enough reason left, and knowledge on how to interpret what is real and what isn’t, to allow me to seek medical attention.

Short version of the above paragraph: our senses need not to be perfect, but our brains must be focused on reality. Once our brain is struggling to identify what is real, and what isn’t, that is the time to seek medical attention. However, as long as the brain is focused, then the senses can tell us whatever it is that is real or not, and we can acquire more information to find out if its real, or we can dismiss it.

13

Bold Standard: I’m not sure I understand your claim about the meaning of “accurate knowledge”.

I’m not using these terms in a nonstandard way. Here’s the definition of “accurate” given by dictionary.com:

ac·cu·rate

adj.

  1. Conforming exactly to fact; errorless.

  2. Deviating only slightly or within acceptable limits from a standard.

  3. Capable of providing a correct reading or measurement: an accurate scale.

  4. Acting or performing with care and precision; meticulous: an accurate proofreader.

3 is the closest meaning to the way I meant it, but 1 and 2 could work.

Our senses are a device. Now suppose some device measures temperature, and it has an error range of 1 degree (+/-).

Is that device “accurate”? I would say no, it has it’s limits.

I can’t imagine how “accurate” could be a valid concept the way you’re using it. In order to be accurate something must have no limits? Isn’t that the same as saying it must have no identity? But then nothing would be accurate and the concept would refer to nothing, so why would we even need it? Accuracy in no way implies omniscience.. Why should it?

And our senses are just the same. We are still, however, able to trace down the inaccuracies because we can gain knowledge of something in different ways.

For example: the blind spot: If you look at an object from a certain distance, your brain will give you a WRONG image of that object (it will attempt to “complete the image”, by making you perceive something that is not actually there), but when you change the distance or change the location of your focus, then you can see another image. When you integrate your knowledge you realize that one of the images must be WRONG, and you run more tests to see which one is wrong, and why.

It would be helpful to clearly distinguish between sensation, perception, and conceptualization. There definitely seems to be some equivocation between the three here.

which would be like learning to use a device in it’s range of accuracy, learning when a device is reliable.

So now the senses are capable of accuracy and reliability? Which position are you taking?

Our eyes are not a photon-meter, and thus they do not give accurate knowledge about the wavelength reflected by the object.

hmm, I’m sorry, but this strikes me as a complete non-sequitur. Do you propose that if our eyes were a photon-meter, then they would give accurate knowledge about wavelengths? Do photon-meters not have ranges of error or limits? And who ever said that sense-perception gives accurate knowledge? I only ever said that it gives accurate information (data), but knowledge necessarily involves conceptualization, and that is where error can certainly occur.

14

I believe I can bring a unique perspective into this conversation. I will tell you what I think, then I will give my real life justification on why I think what I think (I know this sentence sounds confusing, but please, read my entire post, then you would understand).

First, it is true that our senses can provide the brain with wrong data, which happens all the time. However, a rational person would be able to use his other senses to verify if one sense is giving him incorrect information.

While what you say makes sense from a certain perspective, you can still fall prey to attacks by skeptics, who will ask you how you know any of your senses are working.

Since this is an Objectivist forum, let me provide the Oist answer that helped inoculate me from attacks against the validity of the senses.

A vital point is order of learning. When a baby opens his eyes, ears, etc., to take in the world what he gets are percepts. For instance, he sees a ball, his mother, a lamp, a window, etc. These are his first experiences of the world. Whenever any of us opens our eyes in the morning, we get the same sort of input, perceptual input. This is the “form” in which we see the world. It takes a lot of learning to get to the stage where you discover you have eyes, and still more to get to the stage where you realize you are a conscious being and that you have senses that must work to take in information. In other words, it’s a long, long way down the chain of knowledge before you even can ask the question “are my senses valid?”

All of your knowledge to that point, and prior, was based on perception. So, you’ve reached this knowledge state, and at that point you ask the question “are my senses valid?”. The question itself is invalidated, because the foundation on which it is built demands that the senses are valid implicitly. The only way you can be aware that you have senses is if the knowledge you gained via your percepts is valid. Ayn Rand used the phrasing “you must use your senses to deny them”.

Another way to put this is that you can’t rationalistically use your senses as the starting point when discussing their validity. That would be a floating abstraction, detached from the facts. The senses are 100% valid. There are questions of what aspect of reality they are giving you. In that realm, you can talk about accuracy I suppose, given a certain standard against which to measure.