Because that I said you are never not perceiving the world? — Pantagruel

If you have anything constructive to add to the topic, I would advise you to read at least on Hume or Kant, and bring your own arguments on the points rather than emotionally lashing out to people, please. That would help.
I don't think you had a least manner or proper arguments on the topic from your postings to be fair.

Think about what this says. "Prove that there is a world". Whatever doubts exist with respect to the existence of the world likewise exist with respect to any proofs which you might append to that. As to believing in the world when not perceiving it, you are always perceiving something. So just because you don't continue to see the back of something when you move to the front is no warrant to believe the back disappeared. If you are completely unconscious, having no cognitions of any kind, it is just as likely that you have ceased to exist as has the world. In fact, the former seems more likely. — Pantagruel

Not sure if this poster has read even single book on Philosophy in his whole life. Sounds like just making random statements on nothing.

I see. I just don’t see how one could definitively prove there is a world—it is just the best explanation of what one is experiencing. — Bob Ross

I agree. We are trying to see the arguments either to prove, disprove or the question is illogical itself. The conclusions will only be evident from good arguments. But still I felt bringing experience to the argument sounded too solipsistic.

And the main topic OP is not to prove the existence of the World. But trying to see the arguments on the reasons for believing in the existence of the world when not perceiving it.

This is an impossible task, because all the direct knowledge we have of anything is a part of that personal experience that you mentioned: you are asking for that which is impossible to attain. — Bob Ross

Science seeks objective knowledge, so does Philosophy too. For the course of achieving the possible objective truths, they apply reasoning, observations, critical analysis on the data and issues. It is not total impossibility although challenging at times.

Hume displays a slightly faulty way of understanding sensation. He thought that we sense the world to be in a specific condition (like a state of existence) at one time, then we sense another condition at a later time, — Metaphysician Undercover

Hume takes the reverse perspective, assuming that we sense the sameness (when we really sense activity), and then he argues that change to the world must be justified by the mind. — Metaphysician Undercover

Good point and interesting analysis. Any relevant quotes from Hume?

That's funny. I said the same thing with respect to the thread on empirical normativity. Which goes to show you that consensus forms an integral component of cognition. — Pantagruel

Sounds like another case of projection defence mechanism. :smirk:

Obviously. But observation is not limited to science alone. The quality of the observations or the focus of observation, or how they're gone about is what defines whether it's scientific or not — Benj96

Obviously, but not necessarily. Bear in mind that some of the greatest scientific discoveries were from random, accidental and leisurely observations too.

Newton's discovery of gravity by watching the apples dropping from the trees, and Flemings discovery of the Penicillin from a mouldy Petri dish come to mind.

This is exactly my point: you can’t claim you are experiencing if there isn’t something which you are experiencing. Whether or not ‘I’ or everyone exists in that world which you experience is, at this stage of the argument, irrelevant. Perhaps I misunderstood your OP, but I thought you were arguing that you don’t believe in any world at all: is that incorrect? — Bob Ross

I am not so sure if having experience is strong evidence for the existence of a world or the world. Because experience is an abscure concept, which is a private mental event.

You may claim that you have experience of something, but how do I know that something was not your fantasy, imagination or dreams?

The OP does not deny the existence of the world, but it is asking for the reasons for believing in the world's existence.  This is a classic philosophical topic which has been discussed since the ancient Greek era.  But OP is most intimately related to Hume's argument and possibly to Kant's Thing-in-Itself as well. (There have been debates on TII whether it is noumena which is unknowable, or is it possible phenomena which is unknowable but conceivable).

So it is not some meaningless topic created by an ailing guy needing a cure like  claimed in his post. 

 The main aim of the OP is how different reasonings are between the traditional philosophers and currently living people in terms of scepticism regarding the existence of the world, and how some individuals perspectives can be different from the others, and trying to learn more about the scepticism in line with Epistemology and Metaphysics topics.

Of course we cannot derive from logic that we need something to experience to experience in the first place: but that is true of virtually everything since logic only pertains to the form of the argument. — Bob Ross

You are correct. Logic doesn't tell you anything. But we apply logical thinkings into these abcure issues trying to come to more certain conclusions. Until we apply the logical thinking with the contents, Logic is not a Logic. ( You might recall that I have been claiming that in the other threads i.e. Logic needs contents to operate as a Logic.)

Epistemically, I think that experience itself presupposed that which is being experienced. — Bob Ross

I think experience is too abscure, and private mental events to qualify as the objective ground for the existence of the world or a world. We are looking for more objective reasons than personal experience for the evidence i.e. you may claim that you have experienced something therefore that something must exit, but why should I trust that claim? The claim is lacking objectivity.

ps: abscure = abstract and obscure

It's more than that. It's actually a philosophical nuance of realism. — L'éléphant

Suppose Camus and Sartre wrote great novels for expressing their philosophical ideas in them.

It only takes a grain of sand to know the world. — L'éléphant

That sounds poetic metaphor.

The Humean presumption that we have experiences prior to reasoning renders the idea unimaginable. From that perspective, the answer to your question, 'is there a reason to believe in the existence of the world?' is no. — Paine

OK, there is no reason to believe in the existence of the world. Fair enough. I missed your answer No because it was in the small letters.

Hume makes clear on the logical reasons why our belief in the external world is unfounded and unjustified.
1. All we see is impressions of the external objects and bodies in the world.  When we see a tree, the shape, size of the tree changes as we move around the tree.  The tree remains the same, but our perception of the tree changes as we move closer, farther and around it.  All we see is the impression (sense-data) of the tree, not the tree itself.

2. When we press our eyes with our fingers and see the tree, the tree appears in double image.  The tree is one, but the image we see is two.  Which is the real? The tree is real, because it is the object we see, and it is a tree at all other times when we don't press our eyes. Our perceptions can be false at times.

3. Therefore, all we perceive is the impression of the external objects in the world, not the real objects and bodies themselves.  We cannot say the impression of the object is same as the object itself, because they must be different entities in nature.

You keep using the world to imagine the scenario that it does not exist. — Paine

Could you please point out which part of the world scenario doesn't exist? :)

What is a 'logical legitimate perception? The Humean presumption that we have experiences prior to reasoning renders the idea unimaginable. From that perspective, the answer to your question, 'is there a reason to believe in the existence of the world?' is no.

But we do not need an answer to that to do anything else beyond the question. That is in contrast to philosophical questions that are concerned with how we inquire into the nature of beings. — Paine

It means sensory perceptions which are logically verified with reasonable warrant, and justified as valid knowledge.  Most sensory perception in daily life can be unclear, fleeting and unjustified due to lack of focused attention, justification and warrant for certainty and accuracy.  

Humean reason is either demonstrative reason or inductive reasoning which are like inferencing, so his definition of reason seems narrower and much limited capacity than the other Philosophers such as Kant.

Do you then agree that Hume's view is correct?  In my opinion, Hume's premise that the belief in the existence of the world existed before the question has been asked, can be valid, but would he not agree that the belief requires justification and proof, and even if it were justified and verified belief, the external world is subject to constant and unpredictable changes through time? And does the belief that existed prior to the reasoning have 100% warrant for absolute accuracy too?

And according to Hume, reason keeps asking and tries to ensure more accuracy and certainty on the knowledge it is inspecting, but the more it reflects, the less accurate, and less certain the knowledge and beliefs becomes due to the nature of the external world - changing and fleeting. But that is the nature of human reasoning, so why does he deny the point of reasoning for justification of the beliefs on the existence of the world? Doesn't it sound like a contradiction?
Should he not have said that for more accuracy and certainty of the belief on the existence of the world, on-going reasoning is needed accompanied by new up-to-date sensory perception on the world when and wherever possible, which will provide us with more justified belief on the existence?

I am minded of the scene in the Odyssey where dead souls in Hades can speak for a short while if blood from a living person is poured into their cup. You imagine a visitor who demands to know why the soul does not speak when no blood is offered. — Paine

Maybe the soul wanted a nice glass of red wine instead of blood? :)

How important should we make consciousness when we consider physics? This is sort of a hard problem question of a nuanced format. — Benj96

Being simply conscious is not observation. All Science will degrade into superstition without observation. Observation is the key method in any Science.

It involves other aspects of cognition the development of which are a prerequisite to our being able to engage in logical reasoning. For example pattern recognition: — wonderer1

Would it enable us to extend our scope of the visual perception of the world?
I was trying to figure out how much of the contents of the earth I was perceiving at any given time from my own geographic location. I was perceiving the road in front of my house, the hill across the field, a few housing estate with the houses, some shops, the passing cars and pedestrians on the paving blocks, a patch of the sky, and the front and back garden in my house. The total objects in the space I was observing would be perhaps 0.000000000000000000000000000000000000001% or even much much less of the whole earth. I was not sure if my perception of the real time vision would actually be counted for as a legitimate perception of the world in any sense at all be it logical, epistemic or physical perspective.

Why should I believe in the existence of the world? By the way, what is the world? Do any of the other humans have a different scope of direct visual perception of the world purely using the sense organs i.e. the eyes and not using any technological and instrumental perceptual aids? This question just prompted me, but I don't know what the answers are, offhand. Do you?

If this reasoning is true, would it be the case that all the folks who claim to believe in the existence of the whole world with confidence and certainty have been hallucinating and delusional all their lives? Or is that reasoning false? What do you say to that?

It's possible, but unless that thought occurs to me, there's no belief in that regard at all. There isn't a continuous belief, let alone object permanence. We can't cross that hurdle. That's why the question doesn't actually make sense. — Throng

Yeah I see your point. I don't deny the world existing in common life as Hume put it. But when I think about it further and deeper, the world becomes more mystery in its definition.
Things definitely exist. People exist too. But not for long. When I reflect on the things in the world and the people I knew, through time they have all gone and changed. They are totally different from what I used to know before, and it will keep changing and disappearing.

I am not sure what objects must be included in the definition of the world either. All the countries on the earth. and the oceans and sky? There seem to be more than that in the world such as all the celestial objects in the sky, and all the molecules and particles in the vegetables and forests ... etc etc? I mean are they the world? I am not sure.

And all the people living on the earth and me, are we part of the world? Or are we the aliens from another universe temporarily visiting the earth? We are in the world, but that doesn't mean we are the world. If you make coffee and pour into the cup, is it cup? or coffee? Something is in the cup, doesn't mean it is the cup. We are in the world, but we are not the world surely.

But the people in ordinary life don't care about these things at all, and they just keep living. So why are we thinking about these issues? Isn't it what Philosophy about? Wonders about the world, life, perceptions and thoughts. If some says it is not, then what is Philosophy in their minds?

When observation is not operational?
Sometimes the way you say things makes it a bit harder to provide an explanation. But yes, if I'm not now seeing the cup I saw in the sink earlier (because now I'm sitting in the living room), I still believe that it's in the sink unless someone else took it from there. — L'éléphant

When you said, your perception is based on observation, it sounded more intense and purposeful perceptual activity than simply saying "seeing" "visualising" or "perceiving". Observation also sounds like scientific monitoring, inspecting, surveying and examining with visual aid instruments such as microscopes, telescopes and binoculars.

When you observe an object using one of these instruments, and see something that wasn't there when seeing with naked eyes, you tend to be forced to believe in the existence with more assurance, because let's say, you were observing the Moon with a telescope at night, you will see the crates on the Moon. When you see the Moon with the naked eyes, there are no crates visible on the Moon. But because you are using the telescope to see the Moon, and the crates are visible. From the telescopic images and the details that you read about the Moon, now the existence of the crates on the Moon is something that is factual knowledge that you observed, experienced and verified.

So next time when you see the Moon with your naked eyes, and it appears as a shiny round gold coloured smooth object in the sky, you are forced to believe that the Moon has loads of crates on the surface in reality. That is what I meant by when your observation is not operational to imply the mechanised purposeful and motivated act of perception.

So your belief in the existence of the crates on the Moon is based on your memory of the observation and the information about the Moon you read. I suppose you have not been to the Moon yourself. :)

And you keep believing in the existence of the crates on the Moon, even while not seeing or observing the crates on the Moon. As you say this type of observation is conscious and meditated activity, and affords you with a firm solid warrant and ground for the belief in the existence.

As I made clear in the OP, I am not denying the existence of the world at all. I am interested to see the arguments and logical reasoning on what reason or ground our belief in the existence of the world is based.

Could it be only reasoning? Or could it be some other mental events and activities? Or as Hume says, could it be our customs, habits and instincts to believe in the existence of the world?

Nothing forces me to believe in this. It's the theory of object permanence. We naturally believe that objects continue to exist when we aren't looking at them due to our experience with the tangible world beginning at birth. Again, this supports the idea that observation is not based on logical thinking. While logic can help demonstrate that things exist, it cannot make us believe that things exist because this latter idea is developed in us overtime. — L'éléphant

There is a difference between your cup in the kitchen and the existence of the world.
When you say X exists, exist is a predicate of X. It is describing the state of X as existing.
All descriptions imply more information on the subject it describes. You say that you believe in the existence of the cup in the kitchen, and there is no logical reasoning involved in your statement, claim or belief of the existence, because you saw it. Your belief is based on your memory of seeing it, and what else could it be? Your natural instinct to believe in something when you see something?

I am wondering if your memory and the natural instinct could be an infallible ground for beliefs and knowledge. Because all memories tend to fade away through time, and what we call the natural instinct sounds vague. Are we all endowed with the same natural instinct? Does it work infallibly all the time in all cases? How accurate is it in warranting our beliefs? All these questions arise naturally.

And the predicate Existing and Exists is carrying more implications. When X exists, it exists in a location and space and time. So you can ask where the cup exists? The answer would be "in the kitchen". Further questions such as "When does it exist in the kitchen?" is possible. The answer would be "This morning." There is always the possibility that these answers and facts could be all false. As you indicated, what if someone moved it away to the dishwasher? Or the cup was broken and put out in the bin. There are possibilities of these happenings with the cup. Do the answers to the further questions have solid firm ground for accurate information attached to the predicate "Exist", and the statement "The cup exists?"

But when it is the case of the existence of the world, there are more ambiguities. You say "The world exists." Why is it true that the world exists? You say "It exists because I observed it."
But what did you actually observe? Was it the whole world? Does it include all the molecules, and particles in the universe? Does it include all the countries on the earth? And the oceans? The sky? The stars? The galaxies?. You say "No. I see the streets, cars and some patch of sky, the walls of my house and my room and the kitchen". Well it is not the whole world is it? What does the world mean?

Where does the world exist? You say "In the world." Does the world exist in the world? Is it not a tautology? When has it been existing from and for how long? From a long time ago? 46 billion years ago? Are you sure it is the time it has been existing? Is it just a guessing time of existence for the earth? What about all the stars? The sky? The space?
There are lots of contradictions, tautologies and mysteries with these possible questions and answers regarding the existence of the world, which don't quite make sense or add up.

We come to a conclusion. Then is it even possible to say that "The world exists." in a logical sense? Is our belief in the existence of the cup justified?

1. My experience of things strikes me as I am really in a world experiencing those things; and
2. Experience (and especially perception) presupposes a world in the first place. — Bob Ross

you accept that experience is about something, then why don't you accept that there is a world? I am confused. — Bob Ross

1. For experiencing something, you don't need the world.  But you need a world.  There are many worlds that you can experience, but a world you experience doesn't have to be part of the world. A virtual world in computer games, or an imaginary world in your mind or a poetry or novel, or a place in a painting or film, are they part of the world?  I am not sure if they are. 

They exist in totally different ways and in different forms, which have nothing or little to do with the physical world we live in.  But before that, what is the definition of the world?  Do you include all the particles and molecules in the universe into the world? Or with all that plus all the astronomical objects in space? Or is it just the earth we live in?  I mean the thing called the world itself is too vague for us to know if all those other abstract worlds and multiverse and parallel worlds are part of it or not.

With above points in mind, to experience a virtual world in a computer game, do you need the world as a precondition for the experience? Are we certain that the virtual world is part of the world we are not sure what it is in actuality? In what way a virtual world belongs to the world we live in, and why is it the same or part of it? Is the galaxy part of the world? The blackholes? The space? A place you saw in your dream?

2. I don't think you need the world to have experience logically and epistemically. To begin with, experience without something is again a vague concept. It includes all the mental and physical interactions with something, and something here can be anything (because you excluded something, and just specified "experience" on its own). Why should the world be presupposed for experience, when we don't even know what experience we are talking about?

I don't know why there is something rather than nothing, — Throng

Could it be the case there is something rather than nothing, because you perceived something rather than nothing?

No problem.. I like diversity on this site and people who hold different views to my own. :pray: If everyone agreed, wouldn't life be boring? — Tom Storm

I agree with you. :up: It would be pure boring for sure, if everyone had same views on everything. :wink:

No no, I am not bothered at all. I was just a bit surprised at his post using the derogatory word (well here, it is definitely derogatory and ill mannered word).
So I told him what I thought and felt about the post, and that is all there is to it. I don't dwell on it :) Thank you for your concern and care. Much appreciated.

It turns out that Heinlein's "fair witness" is the only actually correct way of doing this. While one is perceiving the existence of the world one has complete proof that the world exists at least in the sense of a set of (what at least appears to be) sensory perceptions.

This remains true even if the world never physically existed. When one no longer is perceiving objects, then it would be the case that these objects have utterly ceased to exist in every sense (besides memories of them) when these objects are mere projections from one's own mind. — PL Olcott

Yeah, this sounds interesting. I will do some reading and search on Heinlein's Fair Witness (never heard of the name before), and have some contemplation on it. Will get back to you if I have any points to discuss or ask.

The only path to the actual truth is to continue to hypothesize possibilities until they are conclusively proven to be definitely false. Both belief and disbelief tend to short-circuit this. — PL Olcott

Wow, yeah, this is what I believe too. :up:

I was talking about the OP in general how it went so far, because you said

For now, you will have to endure the confusion. — flannel jesus

.

I see. I think this is just a turn of phrase. — Tom Storm

Maybe it is used different ways where you live, but here where I live, if one describes someone as ailing, then it is seriously rude. :roll:

No no, that wasn't about you. I think you are very sensitive. We have exchanged our views and there were some differences and mutual misunderstandings, but we sorted out all OK, and agreed to move on. That is my understanding. :blush:

:cool: :ok:

I don't understand your reaction. I read 180 Proof's contribution as a reasonable response, which was located in the philosophical tradition. I found it helpful. — Tom Storm

I thought his using the word "ailing" in his reply was not a good manner in public writing.

It's not an a priori truth in the traditional sense, because its falsehood is logically possible. I'm simply saying ~solipsism is a rational belief. — Relativist

Ok. I see. Good argument on your original post, I think. :up:

No insult. I don't see why you should feel insulted. I was only trying to make you to see the point, because you seem to be missing the point, from the very start.

If I admit what you want me to admit, would it make you happy? :rofl:

We innately know (non-verbally) there exists an external world, and proceed to learn how to interact with it. — Relativist

Do you suggest that the external world is an inborn (a priori) concept?

:cool: :ok: There are more well tuned posters who are giving excellent write-ups, and they alone compensate for any and all the confusions, and makes the OP worthwhile, because as I am getting the constructive and interesting responses, they give me motive to do research, readings and study on the points. This is excellent opportunity for learning.

But we can learn from confusions too - how human minds work for different people, and we can notice the backgrounds of their ill intentions and negative motive for the aggressive responses, which has nothing to do with philosophy or the OP. It is all being noted, nothing goes missing or wasted. :)

It is? Your title implies it's about everyone who believes the world exists. I suspect I'm not the only one who thinks so. — flannel jesus

I have been repeating myself about 1000 times so far this topic is asking for logical ground / reasons for believing in the existence of the world. Not presuming or claiming on anything. I have been just responding on the individual posts some were excellent, some misunderstood, and some almost insane hysterical tones which are nothing to do with the topic or the truth.

Sure. My definition of realist in this thread was the folks who believe in the objects which they can see only as real existence, since this is a metaphysical and epistemological topic.

And please bear in mind, Afterlife, God and Souls are not necessarily spiritual concepts. They could be just metaphysical and epistemic concepts, which I meant and implied.

Suppose there are different types of realists of course. Are there also idealists, sceptics, immaterialist, anti-realists and non-realists who are realists?

Realism itself makes no claims about God or souls or unicorns or Santa clause — flannel jesus

Obviously you have not seen them getting asked, and giving out their replies. That doesn't follow that they don't make claims on these issues. Other possibility could be that they don't make claims on them because they don't know?

First, let me ask you for a brief elaboration of your own view: what is 'experience' if it is not of something, under your view? That way I can provide some worries I may have with your intuitions and evidence. — Bob Ross

Isn't experience always about something? I used to think that way, but maybe you have idea on experience in general, or experience which is not about something. What would it be from your idea?

"Proof?" I make no positive claim that requires "proof"; simply there are no compelling grounds to even consider that the world is "a long vivid dream or some realistic illusion or hallucination", and therefore, the existence of the world remains self-evident or presupposed by all other true statements of fact. Your OP raises a perennial pseudo-question (à la "Cartesian doubt"), Corvus, and maybe as a cure for what's ailing you, consider Peirce's "The Fixation on Belief" and Wittgenstein's On Certainty. — 180 Proof

Ok fair enough. Quite disappointed on your "vulgar" nature of response in hysterical tone. Enjoy your own recommended readings yourself.

The thought experiment about Solipsism is, of course, endlessly relevant because it can't be disproven. As far as I know, there's no sequence of experiences or observations one could have to prove this isn't all a figment of your imagination, or a virtual world full of NPCs created to keep you entertained and docile, or any number of other infinite fake-world ideas. — flannel jesus

Solipsism sounds controversial, but then the alternatives don't sound much better, do they?
If you look closely, realism is also a type of scepticsm, because there are many things that they don't know about, and cannot prove either as true existing or non-existing,  for example afterlife, God and souls. 

Which passages are you referring to? — Paine

Treatise of Human Nature Part IV. p.188 - p.218
Hume denies reason's ability to warrant us with belief in continued existence of the world when not perceived. He says it is "imagination" which does it.

I believe in the unperceived cup each time I remember it in my mind. Absent the thought, the belief is absent. — Throng

How did you manage to perceive the unperceived cup first place, which caused your belief and memory on the unperceived cup?

The error of assumption is regarding belief as a permanent object - let alone the cup. — Throng

Most of our beliefs can be unfounded and groundless. But we could try to figure out which beliefs are groundless and which are warranted by evidence beliefs. This is partly what the OP is about suppose.

The brain can't tell the difference between a self-generated world and an exogenous one. We almost always automatically believe the world that we are presented with, real or not. It appears that we are 'programmed' to believe in something, no matter what. — punos

I suppose there are many alternative worlds existing out there to believe in too. I asked ChatGPT for type of the alternative worlds available for us. So, the traditional earth bound world is not the only world existing out there. But then would you have to decide on which world is the real one, which are fake and bogus worlds?

Type of Alternative Worlds - from ChatGPT
"The concept of alternative worlds often appears in various contexts, including philosophy, science fiction, and speculative thought. Here are a few ways in which the idea of alternative worlds is explored:

1. **Multiverse Theory:**
In theoretical physics and cosmology, the multiverse hypothesis suggests the existence of multiple universes beyond our observable universe. These universes may have different physical constants, laws of physics, or even entirely different compositions.

2. **Parallel Universes:**
This idea is often explored in science fiction. The concept of parallel universes suggests the existence of multiple, coexisting realities that may differ slightly or significantly from our own. Choices made in one universe might lead to different outcomes in another.

3. **Alternate Realities and Dimensions:**
Some speculative theories propose the existence of alternate dimensions or realities that exist alongside our own. These dimensions might have different rules, properties, or even be entirely inaccessible to us.

4. **Philosophical Thought Experiments:**
Philosophers have often used thought experiments to explore the idea of alternative worlds. For example, the "possible worlds" theory suggests that there are many ways the world could be, and our reality is just one of those possibilities.

5. **Virtual Reality and Simulations:**
In the context of computer science and technology, the idea of simulated worlds or virtual realities explores the concept that our reality might be a constructed simulation rather than an independently existing, "real" world.

6. **Literature and Art:**
Many works of literature, film, and art explore alternative worlds as a creative and imaginative exercise. These worlds can serve as a backdrop for exploring different social, political, or existential themes.

Whether in the realms of science, philosophy, or fiction, the exploration of alternative worlds often serves as a means to question, understand, or escape the limitations of our own reality. It's a rich and diverse topic that spans multiple disciplines and continues to capture the human imagination." - ChatGPT