The senses are fallible, so how can anything be known?

[MegaTherion]

If somebody else tells us that they see the cup, then we are using our senses to hear what the other person is telling us. It is possible that this other person does not actually exist, and the only reason we think it is so is because of flawed perceptions.

Again, it’s possible that I’m hallucinating all of this, but I see no evidence or reason to support that belief.

I know you’re looking for some kind of certainty, but your “curiosity” is going to have to learn to live without it.

Again, I agree that this is obviously not the case. But it would seem that knowledge is uncertain, and we have to, as you say, live our lives under the assumption that our senses are at least somewhat reliable. All I am seeking to do is eliminate the assumption.

We have to make certain rational assumptions in order to learn anything about the world:

1. That an objective world exists
2. That this objective world is relatively consistent
3. That our senses connect us to this objective world to varying degrees of accuracy.

We need to assume them to do science, but science is results-based.

Those assumptions start out as assumptions, but every practical benefit generated by the science built on those assumptions is one piece of evidence that demonstrates how accurate the assumptions are.

There’s a lot of evidence that those assumptions are true – the computer you’re reading this post on is one example. The computer was invented thanks to the science built on those assumptions.

So there’s lots and lots of evidence that the assumptions are true. What’s the evidence that you’re a brain in a vat?

[remember it’s not just one set of senses acquiring the evidence – when I say “evidence” I mean independently confirmable data]

 

[dkdempsey]

Interesting topic here. I’m not a philosopher, but maybe since our senses are fallible, we can only approximate what is known? Maybe it’s more of a question of “more than likely / not as likely”. Not sure, just guessing.

 

[dkdempsey]

I forgot that philosophy asks more questions than answers them!

Yes, it does, doesn’t it.

 

[davidv]

A few thoughts on things that I haven’t seen addressed.

There is very bold assumption buried in the OP that needs to be verified. That being “fallible” = “unreliable”. I don’t accept this assumption. Being fallible does not mean being wrong. It just means that there is potential for error. Also, reliable doesn’t me correct. I just means that it is dependable.

In this context one can speak of degrees of reliability or dependability.

On the topic is knowledge: What we sense is not automatically knowledge. Our reason must interact with our senses and decipher that knowledge which the senses point to.

 

[theotikos]

I was curious about this post so I’m writing in response to it. First, why do philosophers argue that the “senses are fallible”? I don’t get that basis of the argument. Everything we process comes from our five sense and is then perceived as an image, object, thought, person, place, etc. So what is so fallible about that? Are philosophers trying to say that the evidence of scientists are fallible because they use their sense to come to their conclusions? So if there are two cups filled with different substances. One being liquid water and another, dirt, are our senses so fallible that we cannot tell the difference? If sense are fallible than what is truth? What is that can be processed and recognized or internalized as truth? I guess I can see why I never really took an interest into studying philosophy more in depth, though I was told by a student that I was open-minded. What has stuck with me was a quote by a philosopher, oh well I don’t recall his name nor know verbatim of what he said, but he said: there is a 50-50% chance of attaining expectant truth in being a believer and a non-believer. You can die a non-believer and you may find that your disbelief is true. Or you can die and find that your beliefs are true. So who has the upper advantage? He said, which I agree, is the believer.
Which reminds me:
“For those who believe, no explanation is necessary. For those who do not believe, no explanation is possible.”

 

[warpspeedpetey]

A few thoughts on things that I haven’t seen addressed.

There is very bold assumption buried in the OP that needs to be verified. That being “fallible” = “unreliable”. I don’t accept this assumption. Being fallible does not mean being wrong. It just means that there is potential for error. Also, reliable doesn’t me correct. I just means that it is dependable.

good point there.

 

[EphelDuath]

I’m currently thinking about my response to MegaTherion, and I’ll get back to you on that. I will answer the few questions about my inquiry on the reliability of the senses:

There is very bold assumption buried in the OP that needs to be verified. That being “fallible” = “unreliable”. I don’t accept this assumption. Being fallible does not mean being wrong. It just means that there is potential for error. Also, reliable doesn’t me correct. I just means that it is dependable.

“Fallible” means that they can be wrong, hence they are unreliable because it is (supposedly) impossible to know how accurate they are. They could be anywhere from a total hallucination to being just as accurate as we think they are.

On the topic is knowledge: What we sense is not automatically knowledge.

If what we sense is incorrect, then our knowledge (which we base on what we perceive) must be inaccurate as well.

First, why do philosophers argue that the “senses are fallible”? I don’t get that basis of the argument. Everything we process comes from our five sense and is then perceived as an image, object, thought, person, place, etc. So what is so fallible about that?

Think of it this way. If you try to see something very far away, you might get a bad idea of what it is, since your sight may not extend to that distance. Who is to say that as the object comes closer, our sight becomes reasonably accurate? Our perceptions must be good enough to survive, as this is the case with all sentient beings, but that does not necessitate that what we perceive is essentially accurate.

Are philosophers trying to say that the evidence of scientists are fallible because they use their sense to come to their conclusions? So if there are two cups filled with different substances. One being liquid water and another, dirt, are our senses so fallible that we cannot tell the difference?

Well, yes, in a way. The only way you know water exists is because you can taste, feel, touch, smell and/or hear it. Now, suppose you were a terribly insane person and your senses lied to you. Thus, you may perceive water when it does not actually exist. How do you know that you, yourself, are not insane? When somebody says “yes, your senses are true, water exists”, that is you perceiving another human being; who, (1) you only think is there because you perceive him, which is a circular problem; and (2) his senses are possibly just as inaccurate as your own. This is the dilemma.

If sense are fallible than what is truth? What is that can be processed and recognized or internalized as truth?

“For those who believe, no explanation is necessary. For those who do not believe, no explanation is possible.”

I do believe, but I still want an explanation. Perhaps that is arrogant, in which case, I apologize for seeking answers to metaphysical questions that humans should not tackle in the first place.

 

[Gottle_of_Geer]

His argument, I think, is that only the mind can be known to exist with certainty; in other words, our senses could be tricking us into believing that we have a body, when we’re just a brain in a septic tank (yes, a silly scenario, but I’m looking for conclusiveness).

Now, you say that his argument is pseudoscience. That is true, but we cannot assume that science is true, since we’re still stuck in the circle that nothing can be known except through the senses, and our senses are unfalsifiable. Science could also be wrong if we have misperceived some fundamental part of nature. (And again, I’m really not a solipsist, I’m only seeking some certainty to knowledge.)

I agree that it is a bit convoluted. His goal is to eliminate all uncertain knowledge, but his conclusions on metaphysics have a lot of unproven assumptions, like that perfection implies benevolence, or that God cannot deceive. Though to be fair, I don’t think he particularly cared about metaphysics; he was a scientist that didn’t want the Inquisition to bother him.

Unfortunately, God is no less problematic - more so, perhaps.​

Where all of this leaves Thomist confidence in the reliability of the senses - well, that’s another question.

“Pyrrho, thou shouldst be living at this hour…”

 

[greylorn]

All information known to human beings comes through sensory perception. These, of course, are fallible; schizophrenics hear voices that don’t ‘exist’, for example.

So, how can we know that anything exists, if we cannot know anything beyond what we sense with our body? A practical person would say that it does not matter if the world exists or not, since if it did not, then this debate would be useless; but I am not looking for a reason to not doubt, I am looking for an answer to my curiosity.

Now, a possible rebuttal could be that the more people who perceive something, the more likely it is that their collective interpretations of their senses are accurate. By this, I mean that – for example – if you have ten witnesses to an event, it is easier to trust that this event happened than if there was only one witness. One schizophrenic person could imagine something, but it is a far cry to suggest that the Earth’s population of six billion are all schizophrenic themselves. But I do not find this refutation to be convincing. When somebody agrees with you or interacts with you, it could be the case that your mind is imagining the other person. How can you trust the reliability of the senses by arguing that there are other people, whom you yourself only know through your own sensory perceptions?

How would you respond to the question, that all knowledge is biased and unreliable on the grounds that the senses are imperfect?

First, I’d admit that the senses are imperfect, then recognize that human senses are not the problem. They can be enhanced.

The first scientist was a Catholic who did exactly that. By building a worthy telescope and applying it to observations of the solar system, Galileo showed how the mind can enhance human senses. Science has taken Galileo’s ideas and run with them. The images you see when looking at a picture of a distant galaxy taken by the Hubble telescope were made by cameras which contained no film, and which took no pictures.

Galileo also taught us where the true imperfections were. They were not in human senses.

His enhanced images, when presented to the Church along with his conclusions (obvious to a bright 10 year old) were rejected. Not because the images were blurry, or because potential viewers were blind. Only because his ideas conflicted with beliefs.

The willingness to accept ideas invented by man and declare them to be absolute truth is a far greater human deficiency than sensory imperfection.

Finally, note that senses are not a source of knowledge. They are a source of information. The mind is a source of knowledge. Otherwise, you would be working to support your cat or dog, rather than… Oops…

 

[Dameedna]

Ah, yes. Well I’m curious if anybody has anything to say about it, then.

Ultimately, I don’t think you can ever know “for sure”. And yes, its a branch of philosophy and has been studied ad nauseum(not that I’ve read all that much about it mind you).

I go with the premise, that since I “think” I exist, I will make the assumption that I do.

And upon that assumption, I can say I “think” the universe exists(a physical reality), so I make the assumption that it does.

This relates purely to my own ability to percieve myself, and my own ability to percieve my outside world. This…is a place of grounding for me.

Anything “beyond” that, however is up for debate.

At the end of the day the interesting question isn’t “really” about wether or not we exist…but about how do we “know” what we “know”. This leads you down a path all the way to absolutism, relativism etc etc and its interesting even if I find there is too much emphasis on it.

We can never know anything for sure. We desperately want to, but we really can’t. What I think is more important, is for people to actually “recognize” this and to say to themselves, if I can never be sure…then what could existance possibly be about?

If we are clever enough to realize we can never be sure about anything, and are self-aware enough to acknowlege this then what is it really all about?

Maybe…we aren’t meant to “know” all the answers. Perhaps, we are supposed to live and discover them. Of course with that view in mind, I’m obviously not christian.(although I do like philosophy hence the reason I’m on this rather active forum).

 

[Michael_David]

:banghead: OUCH!

:banghead: OUCH! This is not real, it must be my imagination?

:banghead: OUCH! It sure feels real…

Is the brain real? Perhaps it’s a consensus of the 5 senses and they store their own experiences and share this with the other senses?

This sure tastes good… hope it is what I believe it to be. Where did that (hope) come from? And belief? :bigyikes: There is more to ‘me’ then what I think. What? Now I think… this just keeps getting deeper into the woods.

 

[GodLovesTheSpek]

Devine revelation, sacred tradition and Magesterial teaching. All Truth is revealed to us by he who is Truth, God.

 

[otjm]

Or, to make it simpler. We can pet an animal, and our body will perceive it as being a cat; but it might actually be a dog. So while the idea of a cat exists in our minds, the animal that “actually” exists could be a dog. How can we be sure that the animal is a cat, if we can only go by our senses?

Because there are universal properties, and because by observation, we can test against those universal properties.

A sophomore might posit that one cannot speak of a universal concept; but then they go out and use universal concepts in their daily life.

One might be advised not to enter into a philosophical conversation with a sophomore.

 

[otjm]

I don’t want to come to this conclusion, though it seems inevitable until a solution is found. I firmly believe in the Catholic faith, but it would seem that no knowledge can be certain, and we have to take everything we know “on credit”, such as that we aren’t floating brains in a septic tank.

it would appear then that you have never put your hand on a hot stove. It is said that if a cat sits on a hot stove, it doesn’t sit on another hot stove, and a smart cat doesn’t sit on a cold one.

Another one of the semi-universal aphorisms is that doing the same thing over and over again and expecting a different result is one of the signs of insanity.

The questions you ask are important to two groups of people: Sophomores and philosphers. What the first seems ignorant of and the second does not willingly want to discuss is the issue of faith. Whether faith is taken to mean our ability to function in the world, or faith in God, the point remains that faith gets one a lot farther down the road than staring at the lint collecting in one’s navel. One does not need to know absolutely in order to function, and there are universal truths which assist us in the process of getting through the day. There are some who cannot tell the difference between a dog and a cat when they pet it, but they are considered by all others to be lacking is certain mental capacities. The rest of us pretty much don’t make a mistake as to what we are petting, and short of sophomores who wish to challenge us that we don’t really know whether it was a dog or a cat, the rest of us realize that the sophomore is just that. One who knows not, and knows not that they know not.

 

[Danno2281]

I suppose we can’t even be certain of that. If all information comes through the senses, then yes, even the idea that we perceive everything through the senses is but something that we understand only through our perception of the world.

 

[Danno2281]

I suppose we can’t even be certain of that. If all information comes through the senses, then yes, even the idea that we perceive everything through the senses is but something that we understand only through our perception of the world.

The assumption that all knowlede comes through sensory perception denies the possibility of infused knowledge. The question really comes down to what is meant by knowing, a condition classically considered an intentional union sui generis** between knower and known. Generally speaking, at least in the view of moderate realism, the senses are considerd to be infallible when and only when they fully perceive those things that are proper to each of them. This solutioni s, of course, fraught with
uncerainty as to what is full perception, but it is at least consistent in that it permits for both genuine knowledge and deception, dor deception could arise only when something preented full perception, (like smoke and mirrors). The difficulty of knowing whether one’s perception is full remains unresolved but it allows for God to have given us vehicles whereby we can come to Truth.

 

[Dtmccameron]

Ah, yes. Well I’m curious if anybody has anything to say about it, then.

I have something to say! You can’t know! Therefore, you must take it on faith!

As it happens, this insane philosophy can really only, so far as I’ve seen, be contemplated by sane people. The aforementioned schizophrenic would be absolutely certain that his hallucenations were real. He would never consider what you’re considering.

He’s actually the more admirable fellow.

 

[Gottle_of_Geer]

:banghead: OUCH!

:banghead: OUCH! This is not real, it must be my imagination?

:banghead: OUCH! It sure feels real…

Is the brain real? Perhaps it’s a consensus of the 5 senses and they store their own experiences and share this with the other senses?

This sure tastes good… hope it is what I believe it to be.
Where did that (hope) come from? And belief? :bigyikes: There is more to ‘me’ then what I think. What? Now I think… this just keeps getting deeper into the woods.

That might all be only an illusion. Is “being as good in practice as though real” the same as being real ? That seems to be the answer to Dr. Johnson’s refutation of Bishop Berkeley’s Idealism:​

• newworldencyclopedia.org/entry/Berkeley,_George
  (I posted the link after writing the post BTW.) And though (for instance) something may seem pleasant-tasting on a given occasion, that tells us nothing about whether it always will.