Certain knowledge

[samr]

As far as I understand, for Descartes "only certainty can lead to certainty" (Don't remember where I got this phrase from).

Bacon, at least according to George Smith's "Why Atheism" thought that an indirect route to certainity is what takes you there.

But, for Aristotle,

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We suppose ourselves to possess unqualified scientific knowledge of a thing, as opposed to knowing it in the accidental way in which the sophist knows, when we think that we know the cause on which the fact depends, as the cause of that fact and of no other, and, further, that the fact could not be other than it is.

..... By demonstration I mean a syllogism productive of scientific knowledge, a syllogism, that is, the grasp of which is eo ipso such knowledge. Assuming then that my thesis as to the nature of scientific knowing is correct, the premisses of demonstrated knowledge must be true, primary, immediate, better known than and prior to the conclusion, which is further related to them as effect to cause. "

So, it seems to me that for Aristotle, the "only certainty can lead to certainty" attitude does hold. It seems to me a much better way.

However, I do not understand how this is possible. For example, because sense perception can err.

[Dennis Hardin]

The way you have described this question suggests total ignorance of the Objectivist view. Descartes approached certainty purely from a deductive perspective—i.e., His cogito—“I think, therefore I am.” Aristotle’s approach was highly inductive—using experimentation to isolate causal connections. They are about as opposite as they can be,

You are right about one thing: certainty rests on the validity of the senses. The senses, however, do not ‘err.’ It is only our misinterpretation of sensory evidence that can lead us astray

You might want to read David Kelley’s Evidence of the Senses. It is the most rigorous defense of the reliability of the senses you will ever read. If you have not read it, this would be a good place for you to start looking for answers to your questions.

[BaalChatzaf]

You are right about one thing: certainty rests on the validity of the senses. The senses, however, do not ‘err.’ It is only our misinterpretation of sensory evidence that can lead us astray

.

Our senses err by omission. We miss a lot. Have you ever tried seeing in infra-red? You are bound to fail. If you use an infra-red detector you are sensing in the visual range. The device maps infra-red into a portion of the visible spectrum. Our hearing can also be confounded by the addition of "white noise".

Also our senses sometimes distort. Example: The Ames Room illusion. Even if you know how the Ames Room is constructed you cannot help seeing things in the Ames Room in the "wrong size". We have wired in circuits in our brain that are right most of the time, but wrong some of the time and it cannot be helped. One must be aware of the distortion (which is immediate and perceived) and discount it.

Please see: http://en.wikipedia.org/wiki/Ames_room

Another example of deception by the senses (not only human but animal) is camouflage. Blending into the background induces the error of omission. Our visual sense operates in such a way that we weight edges and discontinuities more than smooth blending and continuity. That is why camouflage and "zazzle paint" were so effected. The way we get around this limitation is to use infra-red detectors, charge coupled detectors and radar.

See also http://en.wikipedia.org/wiki/Optical_illusion

Empirical proof that our senses can and sometimes do misrepresent the external world.

So how do we know when we have been fooled? Answer: By contradiction and dissonance among sensory events. The fact that our perceptions of the same objective Out There clash indicates a problem and we have to use our wits to tease apart what is right from what is wrong. One way is to resort to optical and other electromagnetic devices. The non-organic sensors are less susceptible to distortion than the organic devices embedded in our bodies by nature. The spirit and the mind are willing (in a metaphorical sense), but the flesh is sometimes weak.

What is an example of unreliable witnessing? Eye-witnessing.

Please see: http://agora.stanford.edu/sjls/Issue%20One/fisher&tversky.htm

Trust your senses but make sure you double and triple check them.

Ba'al Chatzaf

[syrakusos]

I believe that the Objectivist explanation is, as Dennis said, that the senses report exactly what they perceive. We only interpret the information wrongly. It is why the moon looks large on the horizon. You can use any metric you want, a simple ruler, your thumb, etc., and you will see that the moon is actually the same size on the horizon as at the zenith, but you interpret the presentation as being closer to you because it is part of the ground view.

Usually, we interpret our senses rightly. This is one of the failings in the claim that our senses deceive us. Why us and not trees or whales? Why, of all the living things on earth, are we cursed with senses that do not work? A billion years of evolution lost...

We do perceive infra red. We perceive it as heat. We perceive ultra violet as well when the melanin in our skin turns dark.

As for "certain knowledge:" some is; and some is not. The fallacy in skeptical philosophy is in believing that because some things are uncertain that nothing can be known. The opposite error is absolutism, the denial of uncertainty. Objectivism is rational-empiricism, which means that a claim is certain when it is both observable and explicable. The perception must be reliably interpreted in a consistent theory. One of my favorite quotes is from Cicero's "On the Gods" (De Rerum Deorum): "We know that the gods are real because people have reported seeing them and the senses are valid." You see, part of the theory is missing there...

[BaalChatzaf]

We do perceive infra red. We perceive it as heat. We perceive ultra violet as well when the melanin in our skin turns dark.

Only part way into that part of the spectrum and we do not -focus- infra-red. We do not have a lens to do it.

In short, in the infra-red range we loose the details or never get them in the first place.

We do not perceive UV high into the spectrum and again we do not focus it. Details are lost or never gotten.

There is no bright line between the sense organ and the brain. Your retina is a forward extension of your visual cortex at the end of a pair of long skinny nerve cables. In short your retina is your brain and your brain is your mind.

This separation: Sense which gets it right and mind which gets it wrong is not based on any physiological fact.

And if "mind" could regulate how we perceive, we would not be deceived by the Ames Room Illusion after we found out how it works.

But, alas, we are.

Take your senses seriously. Trust but verify.

Ba'al Chatzaf

[syrakusos]

We do perceive infra red. We perceive it as heat. We perceive ultra violet as well when the melanin in our skin turns dark.

Only part way into that part of the spectrum and we do not -focus- infra-red. We do not have a lens to do it. ... And if "mind" could regulate how we perceive, we would not be deceived by the Ames Room Illusion after we found out how it works. But, alas, we are. Take your senses seriously. Trust but verify.

But if the senses are not trustworthy, how can we verify? Successive approximations of "perhaps absolute" are a failure mode. Thus, the problem of induction and the many attempts to ignore it, claim it, or solve it. Objectivism solves it. Rational-empiricism works because it is right.

It is true that we cannot focus infrared. But we cannot hear it either. When air molecules increase their momenta from kinetic heating, we do not hear that. (You can hear the wind, I suppose, but only as it moves other things, perhaps if only against your outer ear.) Bees do see into the ultraviolet range. Whether or how their compound eyes "focus" I do not know. My point is only that gross reality affects us in many ways. We have more than five senses.

Ultimately, however, this discussion only demonstrates the uselessness of isolated facts. Von Mises noted that socialists and capitalists often agree on the facts - a certain commodity had some price in a place and time - what they disagree about is what the facts mean. Here, too, if you begin with the assumption that certainty is impossilble, you will find evidence all over the place to validate your uncertain uncertainty. If you accept that knowledge, even final and absolute knowledge, is possible, probable, or (like me) unavoidable, then the facts are all around you, also.

The blog OrgTheory is written by sociologists of economics, Brayden King, Fabio Rojas, et al. On April 11, 2011, Brayden King posted "When Evidence Isn't Convincing." It summarized research by Daniel Kahan which merits wide publicity. ... Originally published by the Yale Law School as "Research Paper #205: Cultural Cognition of Scientific Consensus by Dan M. Kahan, Hank Jenkins-Smith and Donald Braman," the paper can be downloaded without charge from ... our comrades at Mother Jones who also offer it here. (From my blog, NecessaryFacts, September 13, 2011.)

[BaalChatzaf]

But if the senses are not trustworthy, how can we verify? Successive approximations of "perhaps absolute" are a failure mode. Thus, the problem of induction and the many attempts to ignore it, claim it, or solve it. Objectivism solves it. Rational-empiricism works because it is right.

We have more than one sense and they all do not get screwed up the same way at the same time. Also within a great range of conditions the major senses like touch, hearing and sigh work well enough to keep us synchronized with physical reality to survive.

Also, there is witness. Not everyone is fooled the same way at once, so one can compare notes with other witnesses to tease out a true enough impression of the world.

Then, lastly, there are instruments that are not fooled, or at least the theory of their operation says they are not fooled. Use the instruments to augment the natural senses.

For example radar would make short work of the Ames room or sonar.

Ba'al Chatzaf

[Dennis Hardin]

We have more than one sense and they all do not get screwed up the same way at the same time. Also within a great range of conditions the major senses like touch, hearing and sigh work well enough to keep us synchronized with physical reality to survive.

Ba'al Chatzaf

Perception is purely a physical, automatic process, Bob. I’m surprised you would be inclined to introduce any mystical deceptive forces into the mix. The senses themselves don’t have any power to alter the data. They just pick up sound waves, light waves, textures, et. al. from the outside world and convert them into physical signals in the brain. There’s no room for any deception in the process: it’s all physical and automatic. Mistakes happen when we start interpreting the physical data.

The fact that something may “appear” to be something that it isn’t has to do with our expectations about what we see based on past experience. The data have no capacity to deceive or "fool" us. It merely is what it is.

The only unreliability factor has to do with mistakes in perceptual judgment. That's when we get "fooled"--when we make wrong assumptions. We have to learn that we make mistakes when we assume that, for instance, water transmits light waves the same way that air does. It does not, obviously, and our senses are giving us reliable information to the effect that it does not. Otherwise, how would we ever know?

[syrakusos]

Thanks, again, Dennis. We see eye-to-eye on this or we perceive in transducted accord or whatever. The logical error in saying that we cannot be certain has long been exposed. I do agree with Bob that when more than one sense supports a perception, we are more confident because we have more information. But I also know that one is enough. Otherwise the unanswerable question is: How many are enough? Can hearing support touch? Must you have taste to validate balance? Is sight invalid without hearing and taste? (Does it taste like a lion? Let me get closer...)

His claim that we need instruments to ascertain facts denies everything achieved before the invention of each instrument in succession. The circularity should be obvious: how would you know when your instrument was working? Some who looked through Galileo's telescope claimed that the sights were artifacts of the instrument, a cogent philosophical point until and unless the instrument is explained.

You know what the true promise of Objectivism is? It is a future not merely without pernicious legislation and fiat currency but one without silly questions like this. Myself, I would like to know, given the Objectivist epistemology, what's next? Where are the new applications of philosophy? And where are the new problems in philosophy?

[bmacwilliam]

A myopic person sees things differently than a hyperopic, and yet other distortions are inherent with astigmatism; all due to physical construction of the eye before any data reaches the brain.

Dennis wrote: "The only unreliability factor has to do with mistakes in perceptual judgment."

Well, here we have three totally different "unreliability factors" BEFORE perception. Yet the data is all "correct"? Hardly. That would be a contradiction, clearly.

"That's when we get "fooled"--when we make wrong assumptions." Wrong.

This is transparent (no pun intended) nonsense.

Bob

[bmacwilliam]

His claim that we need instruments to ascertain facts denies everything achieved before the invention of each instrument in succession. The circularity should be obvious: how would you know when your instrument was working?

Doesn't deny anything...

Our senses, aided by intruments at times and logic, help guide us to ever-more-reliable conclusions. That's what's "obvious" to me.

Bob

[BaalChatzaf]

The only unreliability factor has to do with mistakes in perceptual judgment. That's when we get "fooled"--when we make wrong assumptions. We have to learn that we make mistakes when we assume that, for instance, water transmits light waves the same way that air does. It does not, obviously, and our senses are giving us reliable information to the effect that it does not. Otherwise, how would we ever know?

Then why do we remain "fooled" by the Ames Room after we learn how the illusion is created?

And the eye does distort data. If it is too long or too short the rays do not focus sharply on the retina. A misshapen eye produces a blurred image. That is why short sighted and far sighted people need glasses.

Ba'al Chatzaf

[Dglgmut]

The only way for our senses to fool us, rather than us misinterpretting sensory information, would be changes to our sense organs - unexpected inconsistencies.

Bob_Mac, if you're eye happened to recieve sense data differently than someone else's eye, that would not make your eye wrong, as long as it imparted reality with consistency.

Ba'al: Ames Room does not decieve our senses, that's how it really looks. Who know's, if that's how every room looked maybe our brain would have trained itself to judge the sensory information differently...

That makes me wish it wasn't unethical to raise a child in an environment where all the rooms were that shape and see him try to manage with regular rooms once he was like 10.

[Brant Gaede]

We are certain about our certainties and frequently wrong. (Of that I am certain.) We are certain about our uncertainties and never wrong. This is why we are certain about certain.

--Brant

when you need me, turn on the signal--I've got transportation and lotsa great toys!

the cave is damp

[Dennis Hardin]

The only unreliability factor has to do with mistakes in perceptual judgment. That's when we get "fooled"--when we make wrong assumptions. We have to learn that we make mistakes when we assume that, for instance, water transmits light waves the same way that air does. It does not, obviously, and our senses are giving us reliable information to the effect that it does not. Otherwise, how would we ever know?

Then why do we remain "fooled" by the Ames Room after we learn how the illusion is created?

And the eye does distort data. If it is too long or too short the rays do not focus sharply on the retina. A misshapen eye produces a blurred image. That is why short sighted and far sighted people need glasses.

Ba'al Chatzaf

That's exactly it--you are not "fooled" by it once you understand the physical aspects of how the illusion is created, any more than you would insist that the stick in the water is actually bent.

The blurry image presented to the brain by a misshapen eye is also the product of an automatic, physical interaction. The data which a nearsighted (or farsighted) person receives gives them accurate information about a problem with their eyes. When a camera captures a blurry image, would you say that the camera is "fooling" you? Would someone looking at the picture be likely to conclude that the object lacks clearly defined boundaries? Of course not. The distorted image provides accurate data demonstrating that something needs to be corrected.

The distortion in the image is also part of the data being transmitted. Physical properties don't lie or deceive, but the brain that interprets the data has to learn to decipher the information accurately--and then buy a pair of glasses.

[anthony]

Well, certainly. We don't believe we are deaf because we don't possess the incredible aural range a dog has - or incompetent to see, although our eyes have nothing like the resolution of an eagle's.

One day in my late 30's I accompanied my friend to his optometrist, and decided, wth, lets see how my vision is, and took the examination. The opto clicked away with the test lenses, and finally asked me what I did for a living. When I told him photography, he packed up laughing.

"But you're blind!" he said. He explained how the brain's optical centre gradually compensates for(in my case) increasing astigmatism - adding the acutance that the eye has lost. Only with specs did I recognize the difference.

[BaalChatzaf]

]

That's exactly it--you are not "fooled" by it once you understand the physical aspects of how the illusion is created, any more than you would insist that the stick in the water is actually bent.

Why is it that nobody is ever "unfooled" by the Ames Room Illusion even after they understand why it produces the illusion?

Ba'al Chatzaf

[Dennis Hardin]

That's exactly it--you are not "fooled" by it once you understand the physical aspects of how the illusion is created, any more than you would insist that the stick in the water is actually bent.

Why is it that nobody is ever "unfooled" by the Ames Room Illusion even after they understand why it produces the illusion?

Ba'al Chatzaf

Why is it that the pencil doesn't appear straight even after you know that the water deflects the light rays?

Because the water still deflects the light rays, even after you know that it does.

[BaalChatzaf]

That's exactly it--you are not "fooled" by it once you understand the physical aspects of how the illusion is created, any more than you would insist that the stick in the water is actually bent.

Why is it that nobody is ever "unfooled" by the Ames Room Illusion even after they understand why it produces the illusion?

Ba'al Chatzaf

Why is it that the pencil doesn't appear straight even after you know that the water deflects the light rays?

Because the water still deflects the light rays, even after you know that it does.

There is nothing "deflected" in the Ames Room. The senses are fooled because there are certain interpretation of lighting and angles hard-wired into the visual cortex. The visual cortex cannot interpret the Ames Room as it is. It produces a false impression. Since the eyes are an extension of the brain, in particularly the visual cortex the senses are built to falsify this particular input. It cannot be avoided. From this I conclude the senses are not totally reliable. They present the state of the world right most of the time, but not all of the time. If the visual sense were totally reliable and illusion such as the Ames Room could not be created.

No one seeing the pencil in the water believes the pencil is bent. Why? Because they have handled the pencil and know it is straight and rigid. It is the light that is bent. With the Ames Room there is NO LIGHT BENDING. Period. The problem is with the mechanisms of perception. Most of the time they work. Sometimes they don't.

Ba'al Chatzaf

[Dglgmut]

You could use any optical illusion to defend your point, then. But aren't you shifting your focus away from the senses and toward our brain's automatic treatment of the information, which is basically the same argument Dennis was making?

That reminds me of something I saw a while ago. Dan Dennett talks about optical illusions and such at about 11 min in this video:

The part most pertinent to this conversation is probably at about 16:45. It's the most obvious example of the way our brain alters the images we see based on what (I'd say) has proven useful in our lives, or throughout the evolution of our species.

It would seem these optical illusions are just abusing our brain's mostly effective tools of anticipation.

[Dennis Hardin]

. . . the senses are built to falsify this particular input. . .

The senses are built to receive information, and that is what they are doing in the Ames Room example and in every other instance of perception. That is all they can do. They cannot "falsify" anything. Our minds can err in the interpetation of the data, and often do.

[BaalChatzaf]

. . . the senses are built to falsify this particular input. . .

The senses are built to receive information, and that is what they are doing in the Ames Room example and in every other instance of perception. That is all they can do. They cannot "falsify" anything. Our minds can err in the interpetation of the data, and often do.

The algorithm for the Ames Room is based on well founded knowledge of how the visual cortex determines comparative sizes. The illusion was created deliberately to spoof the working of the visual cortex. And it is not based on a habit. Everyone who has seen the Ames Room for the first time reports the same misjudgment of sizes and no one is able to get rid of the illusion even when they understand how it is implement. It is a fault built in to the way the visual cortex generates size judgments. Fortunately, the defect is not particularly harmful because the Ames Room is a man-made contrivance, not something that appears frequently in nature.

The point of the matter is this: Our senses can be fooled. It is just a fact of life. The world can be made to appear in a way that it really isn't. That is the basis of camouflage, sleight of hand and myriad of other spoofs of our sensory system. And it is well that human senses can be fooled. That is how the Suez Canal was saved during WW2. See http://en.wikipedia.org/wiki/Jasper_Maskelyne.

Maskelyne was a professional illusionist employed by the British Armed forces to bamboozle the Narzi in the North African campaign. He was quite successful. And why was he so successful? Because humans sense can be deceived.

Ba'al Chatzaf

[anthony]

The Ames Room's effect is to fool the brain that the eye perceives a normal

room, when it is actually trapezoidal. I think there have been studies done on how

the brain seeks the simplest 'solution,' first.

Whatever; you notice the demonstration is filmed? Therefore, one, fixed point of view, creating

one particular perspective.

Standing in front of the display in reality - you would very quickly see through the illusion

by simply shifting your head a few centimetres left and right, changing the pov, and spotting

the unnatural perspective.

We do not see statically only - vision is accurate.

[BaalChatzaf]

The Ames Room's effect is to fool the brain that the eye perceives a normal

room, when it is actually trapezoidal. I think there have been studies done on how

the brain seeks the simplest 'solution,' first.

Whatever; you notice the demonstration is filmed? Therefore, one, fixed point of view, creating

one particular perspective.

Standing in front of the display in reality - you would very quickly see through the illusion

by simply shifting your head a few centimetres left and right, changing the pov, and spotting

the unnatural perspective.

We do not see statically only - vision is accurate.

Have you been to the movies lately. Do you see the blank screen between frames? You do not. The recovery time of the rods and cones produces a persistent vision of what IS NOT THERE. Vision is not accurate, which is why we can enjoy movies and T.V.

A motion picture is a sequence of still frames. Do we see them as such. WE DO NOT! Some accuracy that is.

Ba'al Chatzaf

[Brant Gaede]

Evidence of the senses means the brain thinks about what is perceived and comes to right or wrong or no conclusions. You can't render the brain out of the equation then claim the subsequent results prove the senses are invalid and provide wrong data when the lack of thinking should be addressed, not sense distortion, which is all in the brain anyway. Take away the brain and even a bird will crash and burn.

--Brant

tedious