Then the question is how can we be certain, not how do we know things? — Harry Hindu

Well, that depends on whether knowledge requires certainty.

When you observe your experiences it seems pretty clear that there is an external world because it would be a different experience if there wasn't. You might say that there'd be no experience at all. — Harry Hindu

But that external world might be a brain in a vat, a simulation, a dream in God's mind, etc. if we take into account skeptical possibilities.

I'm not quite clear on what the problem is. Don't we acquire knowledge from observations? We don't know anything until we observe it. So the answer is observe it and then you will know. — Harry Hindu

The problem is that our acquisition of knowledge doesn't lead to certainty. Which is usually fine for everyday living, but has issues when doing philosophical inquiry. If we want to know what's real, then we have to deal with skepticism.

That is, even if an individual doesn't perceive the world as it really is, what the individual perceives is influenced by some real things that influence his perception, so the individual perceives what the world really is like when these real influences are taken into account, but the thing is of course the individual doesn't perceive these real influences as long as they mess with his perception. — leo

That makes sense. But then when the individual wants to know what the world's like independent of anyone perceiving it, questions about realism, epistemology and science come into play. And they might want to know this because they think there is a world that's more than just humans perceiving it.

So for example if the individual wishes to know how humans came to be, they have to go beyond human perception to an explanation that gives rise to our individual human perceptions.

So, there's clearly a difference between the world and our thought and belief about it? — creativesoul

Also between our perception of the world and how it is. Science tells us this in a thousand ways.

Seems to me like we do not subject accounts we know to be perception to a supposition of it being an illusion... so I suspect we might be closer to the naive realists than you might think. — TheWillowOfDarkness

Well, with vision we see solid objects and not the mostly empty space they're made of, or all the EM radiation passing through them. We see them as colored. And we seem them from a certain location happening over a certain time interval we can experience (so not nanoseconds).

So that image (or sequence of images) is not exactly what an object is.

Set it out... this difference between world and.... what, exactly are you claiming must be different than the world? — creativesoul

Our experience of the world including perceptions and thoughts.

Our image... as retinal? — creativesoul

That wasn't my metaphor, but visual perception is part of it.

Who's arguing for naive realism? — creativesoul

Sometimes the ordinary language approach seems to be defending a version of naive realism. The point is that we can't just say the world is how we perceive and think it and leave it at that. It's certainly not enough to say that ordinary word usage captures reality.

And the world... — creativesoul

It's obviously somewhat different than the appearance, or naive realism would have gone unquestioned. The "appearance" also includes our conceptualizations of the world.

Yes, basically that's it, although the visual metaphor bothers me a little, because one might argue we're being fooled by thinking only in terms of vision, where illusions can occur. With these sorts of questions, it's important to keep in mind our entire experience of the world, less we be mislead by a metaphor.

But I agree the world is a kind of appearance to us, different from what it is, to some extent, at least.

Ask Pfhorrest

The problem with ordinary objects isn't that we name them, it's that they don't map neatly onto our scientific understanding of the world.

Nope, that's also special pleading: fundamental particles and patterns are just as much things we name as mountains. — TheWillowOfDarkness

I'm a scientific realist, so I'm going to have to draw the line there. We don't understand electrons in terms of something more fundamental, unless string theory turns out to be true. That's not the case with ordinary objects.

Stop using it to do things we cannot do with it. — creativesoul

You mean don't use mountains when doing philosophy?

You realise this is special pleading: the objects matter, rocks, snow and dirt are equally things we have named. If there is a problem with the things we call mountains existing before we name them, the same would be true of matter, rocks, snow and dirt. — TheWillowOfDarkness

Yes, but I was focusing on mountains. We could just say only the fundamental physics stuff exists and the interesting patterns it makes. A chair is just a bunch of particles arranged chair-wise would be one way of saying that.

Well, it's a problem with how we're talking about the world and/or ourselves. Typically, I fix such problems by changing how I talk. — creativesoul

One way would be to stop using the word mountain. But that process might result in a radical revision of language.

My point was how we layer on accumulated knowledge and regard it as if it is our natural intuitive attitude. — I like sushi

Yeah, like how we all know ordinary matter is mostly empty space with electromagnetic bonds holding molecules together tightly enough so that we can't see or put our hands through it without smashing it.

But that wasn't the conception of solidity before atomic theory developed, excepting those from the atomist school of philosophy.

I agree that that's the real problem. Where we will inevitably disagree is how to solve the problem. — creativesoul

What's the solution? Analysis of how the word mountain is used?

Nietzsche would be an alt-right troll and Putin supporter?

As regards total failure, Davidson claims "we cannot make sense of [it]." Perhaps taken to imply the impossibility of total failure. To say "we cannot make sense of [it]," is not to say "it cannot occur." It can possibly occur regardless of our ability to make sense of it. Davidson concedes that though it may be impossible to "make sense" of a "total failure of translatability" neither is it the case that "all speakers of language...share a common scheme": — ZzzoneiroCosm

This reminds me of some of Stanislaw Lem's science fiction work where there is a total failure to communicate. In the Solaris novel, which has been made into two different movies, an alien ocean has been discovered that is a living organism and exhibits some kind of intelligence, but there is a total failure to communicate with it because it is so alien, and the humans cannot get past their own human concepts to make the leap. However, the ocean may face the same problem when it starts recreating other humans from memories of the research crew, including the main character's deceased wife. This is very disturbing and upsetting to the researchers, and it ultimately explains nothing as the physical imitations don't know why they were created by the ocean.

I recall reading that was the Greeks conception of how vision worked. But maybe it varied across cultures and philosophical schools. We do experience vision as if we're looking out through our eyes at the world. It's just that the scientific understanding is also there to correct us. Similar to watching "sunsets" and "sunrises" or not feeling Earth's movement.

Nature doesn't draw lines. We do, and we can be wrong sometimes, depending upon what we're delineating.

If you agree then what's the issue? — creativesoul

Alright, so do mountains exist? And by mountains, I don't mean the rocks, dirt, snow making them up. I mean do objects called mountains exist?

What's the issue here? It's an issue of whether nature is the way we conceptualize it to be. The problem with real mountains as objects is where to draw the line on what constitutes a mountain versus a hill or some other formation. It's also a question of where to delineate the end of a mountain versus the rest of the terrain. And a question of identity over time as the mountain gets worn down. At what point is it no longer a mountain? At what point does it become a mountain?

And it's also a question of whether the snow, rocks, dirt, trees, etc. really do combine together to make a singular object we call a mountain, or whether it's just a bunch of different stuff next to each other.

So yeah, I can agree that Everest existed as lump of different collection of matter prior to humans, but I'm not sure about whether it existed as an object we call a mountain, such that it had properties of being the tallest (from when the Indian tectonic plate pushed it up to the highest point until the present day, not counting underwater mountains).

I think Dummett made similar critiques of realism as well, although I think he tempered it by saying his approach might not work against all cases of realism.

Well, his critique was against transcendental truths, which he said realist statements had to assert.

I favor a linguistic approach to this issue. What exactly do we mean by 'being' and 'independent'? — Eee

It simply means there is more to the world than humans. So evolution, stars, big bang, atoms, disease, animals in the deep sea, maybe alien life, etc. We may or may not come to know about all these things. We certainly won't know everything.

Otherwise, the entire universe collapses to just what humans know and experience. What makes us so special? Why does science tell us we're not?

For a transcendental or Berkeley idealist, are there things that exist independent of their mind, whether it be other minds, or other bodies? — Harry Hindu

Well yeah, they're realists about other minds. Which is open to the same sort of criticism of the OP.

The point is that it doesn't matter whether the external stuff is other ideas, or material, or whatever - only that there is stuff that exists — Harry Hindu

That's true, there are different kinds of realisms. Most of us are realists about some things and not others.

As for the skeptical alternative, that would require a clear definition of what it means to know anything. — Harry Hindu

Yes. Doesn't that tie into the OP's argument?

I think I agree with what you stated there. Except that the world doesn't have to reflect our concepts entirely. We have gotten quite a lot wrong. I guess he means fundamental things like space and time, but even those have undergone revision.

What are the viable alternatives? Are there only two - solipsism and realism? — Harry Hindu

Add transcendental and Berkeley's idealism to the list. Skepticism is that we simply can't know, so that would be fifth one.

But I agree about solipsism, why does it appear as if a world and other people exist?

Is there a correlation between us and the world? If so, then isn't science getting at what is? — Harry Hindu

Yes, I'm a scientific realist. I was just repeating the correlationist argument Meillassoux critiques.

Right, Nagel's point is we can't know therefore science (or objectivity) can't tell us everything.

Block made a similar argument with androids and nations.

The redness I see is just "in my head" and not the same thing as a surface that reflects light at a certain wavelength. — Michael

It almost has to be that way. I guess the color realist would argue that human brains are recreating colors out there in the world, but I'm not sure this always works out with the colors we see versus reflective surfaces and lighting conditions.

Also, because the color we see is because of a small part of the EM spectrum, raising a question as to whether colors are associated with the rest of it, and if not, why not? If our eyes could detect radio rays, would we see some color range coming through the table and all around us? Is visible light special because if reflects off molecular surfaces?

If we deny non-empirical knowledge, the science of mathematics would be impossible. — Mww

True, but we use our experiences to draw the inferences that make most sense of all the empirical data, and form explanations around that. Thus we come to know that vision works differently than how we experience it, which resolves a lot of problems that were noticed a long time ago, such as sticks bent in water.

In this respect, Kant has no problem with objects existing before or without us, he's only making the point things must be explicable in our concepts. Kant, as an emprical realist, has no problem with My Everest existing at a particular height before any humans measure it. — TheWillowOfDarkness

Right, but then this leads to the Meillassoux critique that dinosaurs existed (not really). So we can empirically say humans evolved from earlier life forms, but since we weren't around, we can't assert this to be true. It only appears that way to us, because that's how human minds carve up the world. And thus we can't say anything true outside of ourselves. Science is only concerned with how the world correlates to us, and not how it is.

I find that hugely problematic. Anyway, it's certainly not a realist position.

From this can we rightly assume that the natural human instinct is to view our ‘seeing this tree or that table’ as projected outward rather than as given by external illumination? — I like sushi

Yes, that's how we experience vision.Which is why naive realism doesn't work without a sophisticated philosophical defense. It can't just be asserted or assumed as the premise, since it's been challenged since pretty much day one once people started reflecting.

But back to consciousness.

Along these lines if we talk about ‘what it is like’ what does that sentence mean? The ‘like’ is a redundant word because we’re not really asking about ‘likeness’ at all. To be a bat is to be a bat, and to be human is to be a human. — I like sushi

The "what it is like" is just a way of saying that a bat may have a kind of sensory experience that we don't because bats make use of sonar. If not bats, there are plenty of other examples in the animal kingdom. And anyway, why should we expect human experience to be exhaustive of all possible experience?

"Mt. Everest" picks out a particular mountain. That mountain existed in it's entirety prior to being named. — creativesoul

I agree, but where does nature draw the line on what is Mt. Everest and what isn't?

As for the OP, how do we know it existed before we were around? I think there are good scientific realist reasons for saying so, but regardless a realist needs to defend the assertion that things can exist without us knowing and not just state it.

Do we picture a chair in the room (and no person present)? But then that's just a counterfactual (disembodied) experience. — Michael

That would be naive realism. The chair exists pretty much as we perceive it when we're not around to perceive it. But that obviously has problems, which were noted a long time ago.

We could instead say the lump of matter we consider a chair continues to exist. That's more defensible. But what makes it a chair? Are chairs real? Not the matter itself but the object we call a chair? That's harder to defend, since chairs are a cultural artifact. If humans didn't exist, there would be no chairs to sit in.

But what about mountains? Here it gets murky, because humans don't make mountains. They're already there. But how do we categorize a mountain, single it out, and measure it? Was Everest the tallest mountain before anyone measured its height? What gives tallest its meaning in this case, since the measurement depends on the criteria for being tallest mountain?

We see this problem with whether Pluto should be considered a planet. Nature doesn't care. But we try to be precise with whatever classification scheme works best for orbiting bodies. But then again that implies there are joints to nature science tries to carve at. And on it goes.

Anyway I'm bowing out, I don't want to hijack the thread. — Wayfarer

Wait, what? This is going to be the new 100 page idealism/realism death match. It's way too early to bow out.

You notice the hidden assumption in your last question? The 'real world'? — Wayfarer

So are you saying Kant didn't think the noumena was real?

But he still maintained that in some fundamental sense, time itself was a 'primary intuition' of the observing intelligence, and denied that it had absolute or objective reality; that science itself is still dealing with the realm of phenomena. — Wayfarer

Right, does Kant ever say positively what exists and how it relates to the phenomena? So if time is a mental category, then what does it relate to in the real world?

That question doesn't make sense to me. Does it to you? Is that what you meant to ask? — creativesoul

No, but I can substitute real in there: How dow we know Mt. Everest is real?

Cue ordinary language response.

'Before' implies duration, duration is predicated on there being time, and time is somehow dependent on the perspective of an observer. — Wayfarer

And yet we know about deep time, and we can measure how long Everest has been around.

If Mt Everest were endowed with sentience, he/she/it would probably be incapable of cognising h. sapiens, because we're so tiny, and our lives so ephemeral, that they wouldn't even register in his/her/its
consciousness. Glaciers and rivers, maybe, because they stick around long enough to (ahem) make an impression. — Wayfarer

Probably, but we also know about picoseconds and nanometers, so it's not impossible for a society of sentient mountains to learn about life.

Please set out the referent for the term "that". I — creativesoul

Oh okay, Cart, horse, idealists being trampled.

Mount Everest is the reference of "that". How do we know that Mt. Everest existed before we knew about it?

Please set out the referent of "that". — creativesoul

How do we know "that" numbers exist? Morality, qualia, possible worlds?

Just because you can put a that in front doesn't mean it has a real referent, and we all will take issue with some class of things being considered real.