When did you last believe, and treat, people you see across the street from you as if they were only, e.g., 6 inches tall because that's how they appeared to be when you saw them, and thought that they became 6 feet tall when they crossed the street to speak to you? — Ciceronianus

I got an eye exam the other day, and it was relevant how I saw things, with an objective standard being assumed that I varied from, so I was prescribed glasses to bring my vision into alignnment with what was thought to be the standard.

My vision wasn't so skewed that I saw objects in ways that would suggest a neurological problem (like not adjusting objects properly for distance), but I assume that could also be the case.

That's a pragmatic example of when it matters.

Philosophically it matters because it suggests an interpretative function of the eye apparatus and the brain and how that interplays on the object itself to the extent we may question whether our perception is a match with reality. I would presume that with my glasses off, I do not see objects as they are, but more as they are blurred.

I would presume that with my glasses off, I do not see objects as they are, but more as they are blurred. — Hanover

Well, does the fact that they appear blurred to you with your glasses off persuade you they are or may be blurred?

I don't see how this addresses my previous post. — Luke

Again, I'm referring to "affectation" as defined by Merriam-Webster online as I said in the OP:

Affectation" according to the Merriam-Webster Dictionary Online, is:

"a. Speech or conduct not natural to oneself: an unnatural form of behavior meant especially to impress others; b. the act of taking on or displaying an attitude not natural to oneself or not genuinely felt."

I wouldn't consider it "natural to myself" to believe that someone across the street from me is 5 inches tall, but would consider it "natural to myself" to by surprised by, and to dispute, someone who did believe that.

Well, does the fact that they appear blurred to you with your glasses off persuade you they are or may be blurred? — Ciceronianus

My perception of the apple is blurred without the glasses. If I never had glasses, I would assume the apple and the blurriness were one in the same. My assumption is that there are other distortions between the apple and my perception that are not correctible or that they are correctible by means I don't yet know about.

My perception of the apple is blurred without the glasses. If I never had glasses, I would assume the apple and the blurriness were one in the same. My assumption is that there are other distortions between the apple and my perception that are not correctible or that they are correctible by means I don't yet know about. — Hanover

People who have significant eyesight problems generally know this is the case. Someone nearsighted will come to understand that what appears blurry to them at a distance won't appear blurry when closer to them, and as they live in an environment with others with no such problems, will come to know that they have a problem others don't have. Someone blind will come to know others are not. I think it's unlikely that the nearsighted and the blind will conclude that all are nearsighted and all are blind.

I think it's unlikely that the nearsighted and the blind will conclude that all are nearsighted and all are blind. — Ciceronianus

I think it's unlikely that we are not blind in some regard we don't know about.

I think it's unlikely that we are not blind in some regard we don't know about. — Hanover

It seems unlikely that many people believe this.

seems unlikely that many people believe this. — baker

We are in fact "blind in some regard" whether you believe. You can't see ultraviolet, hear high frequencies, taste certain flavors, feel minute variations, or smell certain smells.

@Hanover
Of course, people will generally make concessions of weakness, fault, or deficit when it comes to small or trivial things.
But they are unlikely to believe (much less openly admit) they might be blind in some way that matters.

course, people will generally make concessions of weakness, fault, or deficit when it comes to small or trivial things.
But they are unlikely to believe (much less openly admit) they might be blind in some way that matters. — baker

I'm pretty sure the vast majority of people admit they can't smell an intruder like a dog.

Again, I'm referring to "affectation" as defined by Merriam-Webster online as I said in the OP:

Affectation" according to the Merriam-Webster Dictionary Online, is:

"a. Speech or conduct not natural to oneself: an unnatural form of behavior meant especially to impress others; b. the act of taking on or displaying an attitude not natural to oneself or not genuinely felt."

I wouldn't consider it "natural to myself" to believe that someone across the street from me is 5 inches tall, but would consider it "natural to myself" to by surprised by, and to dispute, someone who did believe that. — Ciceronianus

What isn't natural for you to believe might be natural for someone else to believe (and vice versa). Again, by what criteria do you judge whether some belief or assumption or philosophy is an affectation? Is it simply when others are lying about their beliefs?

Again, by what criteria do you judge whether some belief or assumption or philosophy is an affectation? — Luke

In this case, by conduct; by how those who maintain that we cannot know the nature of what we deal with everyday, or experience it, or some variant of that position, act every moment. Conduct indicates we have no doubt at all regarding the nature and use of the cup from which we drink coffee (or regarding coffee, for that matter).

One might say "well, that's just how I act in everyday life, not when I'm doing philosophy" or "well, I really do doubt, I just don't act like I doubt" but such responses aren't persuasive, really. They're aspects of the affectation. What can be more natural to us than how we live, how we actually interact with the rest of the world?

We are in fact "blind in some regard" whether you believe. You can't see ultraviolet, hear high frequencies, taste certain flavors, feel minute variations, or smell certain smells. — Hanover

Which is merely to say that we're human beings. One might say the same of any living creature. Are they "blind" as well? We must be omnipotent, be God then, in order not to be "blind"? It seems a rather unusual way to use the word.

Which is merely to say that we're human beings. One might say the same of any living creature. Are they "blind" as well? We must be omnipotent, be God then, in order not to be "blind"? It seems a rather unusual way to use the word. — Ciceronianus

If there is something we do not know, then by definition, we are not omniscient. Your question, as I took it, was why we should ever doubt the accuracy of what we see before us, and that should we so doubt, we do it disingenuously.

You attempted to deal with a very simple case in the OP where you acknowledged that our vision did report to us information that could mislead us into thinking that a person grows in height as we move closer to them, but you correctly pointed out that our vision isn't the only thing that informs us of the world, but that our intelligence does as well. That is, I know you don't get physically larger when I get closer to you or that the straw in the glass of water doesn't actually bend even though it looks that way because I am able to noodle all that in my head and realize such perceptions need to be interpreted by me and with that I can figure out the world in which I live.

I then took a more complex case dealing with a person who might be truly blind to portions of reality incapable of sorting out what the world truly were like as in the case of the approaching subject or the bending straw. That then resulting in efforts to interpret "blind" very narrowly, as in surely someone who needs glasses knows when he's not wearing them that the world isn't actually blurred. I then explained that blindness is any sort of inability to sense things as they are, which is obviously the case because we all know that what we smell isn't what a dog smells. We can also imagine that there are sensations that no organism can detect.

The point of all of this is responsive to what I think is the larger inquiry, and that is whether folks like Descartes are foolish to question that which no one has a basis to question. I think the above discussion does provide such a basis.

If that's the case, though, why purport to think, or believe, otherwise, i.e. contrary to the way in which you actually live your life? — Ciceronianus

It might be the case this answer was already given here — maybe a few times. We act differently from what we believe because it is productive. But though I have no perfect reason to believe there is a truck coming on the other lane, and that my brain is not in a vat, I will still keep driving on my own lane and avoid the incoming truck.

A better example is, even though causation might be just regularity and that there is no guarantee that boiling eggs will make them edible, it is still a good bet to boil my eggs if I want to eat them.

Even if I don't personally believe in the permanence of the self, this belief will lead me nowhere, as I might be wrong and the self does actually stay through time. So I will try not to screw myself by eating junk all day. If I don't act as if I am the same person tomorrow, I won't reap any great benefits now.

To quote someone else, everyone is a realist once they walk out of the door.

Your question, as I took it, was why we should ever doubt the accuracy of what we see before us, and that should we so doubt, we do it disingenuously. — Hanover

There may be instances where doubt is appropriate. I'm trying to address the view that we should doubt in all cases, or cannot know in any case. That view may be based on unwarranted extrapolation from unusual cases to all cases, confusion, or misuse of language, as some philosophers have noted.

I wonder if there are other factors involved which incline some of us to question whether we can really know anything about the world. The reason I wonder that arises from the fact, which I don't think can reasonably be disputed, that we clearly act like we know something about, as we interact with it all the time, change it in various respects, create new constituents of it from existing constituents (furniture, cars, etc.), consume portions of it, and do many things with it all the time, simply by virtue of the fact that we live in it. We do that in most cases without any concern whatsoever that what we interact with may not really be what we think it is, or may be actually be something else. We have no concern, I think, because we have no reason to think that in most cases, and generally can arrive at any explanation in those instances when we do have reason. Why doubt when there's no persuasive reason to doubt?

The point of all of this is responsive to what I think is the larger inquiry, and that is whether folks like Descartes are foolish to question that which no one has a basis to question. I think the above discussion does provide such a basis. — Hanover

That's a fairly good summary of what I think--that's it's (generally) foolish to question that which no one has a basis to question. I disagree with you, though, as nothing I've seen in this thread provides such a basis.

There likely are things about the universe we can't know. We're not omniscient. We're human. These aren't particularly profound observations. It doesn't follow from this that we can't know anything, or can't know what is real.

Things we see are actually made up of things we can't see (though they have been determined). Very well. Again, we're human. We see in most cases exactly what we should see, being human. If that's the case, why is it that what we see isn't really what's there?

When we say we can't know what the world really or actually, I think we make certain assumptions, the primary of which is the assumption that there is something that is real behind what we experience which can't be determined. Something hidden from us because of our nature. It's a kind of religious view, perhaps.

When we say we can't know what the world really or actually, I think we make certain assumptions, the primary of which is the assumption that there is something that is real behind what we experience which can't be determined. Something hidden from us because of our nature. It's a kind of religious view, perhaps. — Ciceronianus

It’s a metaphysical view which formed the basis of thinking for the sciences until recently. It also lends support to particular religious perspectives. The metaphysics dependson the concept of substantiality. Mind and matter are composed of substance. To be a substance is to have intrinsic content, qualities, attributes that persist as self-identical, independently of their interactions with other aspects of the world. Since the mind, with its intrinsic , substantial qualities, differs from the substantial stuff of the external world, its representations of the world will always leave doubt concerning what remains intrinsic to external objects, and thus hidden from the mind’s eye. The question will always be left open as to what extent the mind makes contact with external substance. We only escape this doubt when we cease to assume the idea of intrinsic substance, and opt instead for a radical interconnectedness of subject and object ( Hegelian dialectics, phenomenology, pragmatism, hermeneutics).

We see in most cases exactly what we should see, being human. If that's the case, why is it that what we see isn't really what's there?

When we say we can't know what the world really or actually, I think we make certain assumptions, the primary of which is the assumption that there is something that is real behind what we experience which can't be determined. Something hidden from us because of our nature. It's a kind of religious view, perhaps. — Ciceronianus

Of course it's a religious/spiritual view. Religions/spiritualities start from the premise that _ordinary_ people don't see things "as they reallly are". (To which the religions/spiritualities then offer their solution: "Follow our religion/spirituality and then you will see things as they really are, and then you will be happy/content/self-actualized/self-realized.")

course, people will generally make concessions of weakness, fault, or deficit when it comes to small or trivial things.
But they are unlikely to believe (much less openly admit) they might be blind in some way that matters.
— baker

I'm pretty sure the vast majority of people admit they can't smell an intruder like a dog. — Hanover

Not having senses as acute as those of some animals or technological devices is common to all humans, so nothing special. There's no threat to one's ego to admit to such deficits.

But who would even consider that they might not know the truth about God, or about some moral issue? Even people who style themselves as "seekers" are actually still completely sure about everything.

You can't see ultraviolet — Hanover

The image on the right was taken using film sensitive to reflected (not fluorescent) UV. The other is visible light.

With a bit of help, we can see UV.

Folk seem curiously protective of their affectations.

People who have significant eyesight problems generally know this is the case. Someone nearsighted will come to understand that what appears blurry to them at a distance won't appear blurry when closer to them, and as they live in an environment with others with no such problems, will come to know that they have a problem others don't have. Someone blind will come to know others are not. I think it's unlikely that the nearsighted and the blind will conclude that all are nearsighted and all are blind. — Ciceronianus

Speaking of vision problems: There are vision problems that are impossible to correct or compensate for with various devices. Such as color blindness, or certain depth vision problems (because of which the person cannot "see" some optical illusions). Unlike a person with dioptric problems, such a person never has the chance to experience what it would be like to see "normally". Instead, they have to take on trust that there is something wrong with their vision, and they need to compensate deliberately, both cognitively and behaviorally, in order to function in a world designed by people who mostly don't have such vision problems.

The salient point here is that sometimes we have to take it on trust that there is or might be something wrong with us, or that we have a blindness of some kind, even though we can at best recognize this blindness only indirectly. This having to take things on trust is a significant vulnerability.

With a bit of help, we can see UV. — Banno

With a lot of interpretation.

What can be more natural to us than how we live, how we actually interact with the rest of the world? — Ciceronianus

Cunning.
Man is cunning.

And I refer here to the double meaning of the word "cunning", which in the beginning didn't have the negative connotation it tends to have nowadays.

The salient point here is that sometimes we have to take it on trust that there is or might be something wrong with us, or that we have a blindness of some kind, even though we can at best recognize this blindness only indirectly. This having to take things on trust is a significant vulnerability. — baker

I'm not sure if "on trust" is entirely accurate. I think it would be more a case of making a judgment based on the weight of the evidence, which may be indirect. What's the probability that everyone without the problem would lie to us, or be mistaken?

The question will always be left open as to what extent the mind makes contact with external substance. We only escape this doubt when we cease to assume the idea of intrinsic substance, and opt instead for a radical interconnectedness of subject and object ( Hegelian dialectics, phenomenology, pragmatism, hermeneutics). — Joshs

It seems to me that the view that we can never know the extent to which we (I don't think our minds are separate from us) make contact with the rest of the world is far more radical than the view that we do. The latter is based on what actually takes place to our knowledge when we interact with the rest of the world; the former is based on the belief that what takes place when we do so doesn't matter. What actually happens when we interact with the "external world" is apparently of no value.

I'm not sure if "on trust" is entirely accurate. I think it would be more a case of making a judgment based on the weight of the evidence, which may be indirect. What's the probability that everyone without the problem would lie to us, or be mistaken? — Ciceronianus

It's not about others lying or being mistaken.
My personal example here is that I have a non-dioptric vision problem because of which I can't see some optical illusions, among other things. I remember back in school when other students and the physics textbook were talking about those optical illusions, and I just didn't see them. It's a peculiar situation: other people visibly express emotion over something, are excited, and I don't even see what they're talking about. It was an alienating experience, that's why I remembered it. How does one make sense of this feeling of alienation?

Ah. I see what you mean.

It seems to me that the view that we can never know the extent to which we (I don't think our minds are separate from us) make contact with the rest of the world is far more radical than the view that we do. The latter is based on what actually takes place to our knowledge when we interact with the rest of the world; the former is based on the belief that what takes place when we do so doesn't matter. What actually happens when we interact with the "external world" is apparently of no value. — Ciceronianus

I think that what actually happens when we interact with the world is taken into account by all of the philosophies which
you accuse of affectation in their doubting. This is why they all come up with explanations for why the world makes sense to us. For Descartes God ensures that we have rational facilities which allow us to tell truth from error in our dealings with things. For Kant, it was our innate categories which steered us in the right direction. You undoubtedly have your own explanation as to why we can reliably make sense of our relations with the world. I’m assuming you jettison (doubt) divinely-based a prioris of rationality in favor of empirically-based, biological foundations.

You’ll notice that in order to assert whatever new and improved ground for reason a philosopher is embracing, they have to show why the previous era’s assumptions should be placed in doubt. For instance, although Descartes may have done an awkward job of it , he needed to place in doubt the basis of medieval assumptions concerning knowledge in order to advance his alternative. Similarly, once you put Descartes’ divine source of cogitation into doubt, you take away his justification for rationality. And once you place into doubt Kant’s transcendental categories, you need a new basis for the relation between our conceptual schemes and the world. Your own pragmatically-based grounding of everyday knowledge may be susceptible to doubt on the part of certain contemporary philosophies and psychologies.

When we say we can't know what the world really or actually, I think we make certain assumptions, the primary of which is the assumption that there is something that is real behind what we experience which can't be determined. Something hidden from us because of our nature. It's a kind of religious view, perhaps. — Ciceronianus

We know how things appear to us. There is no guarantee that these appearances give us exhaustive knowledge of how things are or that the nature of things is not (at least partially) hidden from us. It seems to me that to admit this is merely to exercise a modicum of intellectual humility which would make it, if anything, far from being an affectation. Closer to being an affectation would be to claim that what we can experience and understand of the world as it appears to is, or even must be, exhaustive of its nature.