The "sun" "appears" in the "sky" every "day". There's nothing untrue about this. The sun is visible each day from the surface of the planet earth. No amount of trying to enforce semantic technicalities to say this is "unobjective" will change this observable truth.

An observation does not have to amount to a complete description of something, it can be specific, incomplete, or even based on an abstraction. "The sun rises every day" is a very simple observation and the strong inductive argument which arises from it is extremely specific: the sun is visible with predictable regularity. Again this does not say anything about what the sun "is" beyond that whatever it is, "it's visibility from the surface of the earth follows a cyclical pattern". — VagabondSpectre

You seemed to be inclined to attempt to avoid the problem by claiming "semantic technicalities", rather than to face the problem for what it is. The point is, that the precision, accuracy, or even truth of any stated observation, is questionable, even if numerous individuals agree on the terminology of that statement. So your original statement "the sun is visible in the sky every day" is questionable. Is the sun really in the sky? You may now desire to qualify this by saying that the sun "appears" in the sky, but all you do is imply that there is uncertainty as to whether the sun really is in the sky or whether it just appears to be in the sky, and that just verifies my point.

You're still using semantics to try and make your point while ignoring the one you are trying to criticize. — VagabondSpectre

Yes, the point is that semantics is important to objective truth. You seem to think that you can dismiss the problem by saying "that's just semantics". That doesn't make the issue go away, it's just a case of you finding an excuse to ignore it.

Repeatable observations of reliable phenomenon assist in producing models which allow us to reliably predict various aspects of said phenomenon. It's not objective truth; it's reliable and useful truth; that's science. — VagabondSpectre

Models which predict reliably is not truth at all, it's predictability. As I've just demonstrated, the capacity to predict can hide profound falsity which lies beneath. Therefore the capacity to predict is really irrelevant to truth and falsity. Prediction is derived from conclusions of deductive logic. The truth or falsity of the conclusions depends on the truth or falsity of the premises. The premises may be derived from conclusions of inductive reasoning, but the truth or falsity of these inductive conclusions is an issue of semantics. Whether "the sun rises each morning", "water boils at 100 degrees Celsius and freezes at zero", "the sky is blue", are true or not, is an issue of semantics.

The problem that you're pointing out with the statement "the sun rises" (i.e: the sun doesn't actually rise) does not have anything to do with what I'm pointing out about it, which is that whatever the sun is, there is consistency in our observations of it. A pattern is identifiable within those observations, and these particular observations and particular predictions (I could see the sun for the last thousand days therefore I will be able to see it tomorrow) take the form of a strong cumulative argument from observation (inductive reasoning).

Let's go back to the beginning of our disagreement, I said: "Even while our experience might be wholly subjective in any sense of the word, there are still consistencies within and between our experiences. The sun will rise tomorrow is a belief held by all humans because of a very strong cumulative argument (inductive reasoning) coming from our experience of it rising each day"

Then you said:

"The problem here is that the sun really doesn't rise. The scientific explanation of this phenomenon, the illusion that the sun rises day after day, is that the earth is actually spinning. The sun is really not doing anything in this scenario, therefore it is actually false to say that the sun rises.""

If you had charitably interpreted what I was saying, you would have acknowledged that my point was not to say or even imply that "the sun moves through the sky while the earth remains still", but instead that "whatever the sun does (or does not do), it does so with observable consistency, which can be the basis for an inductive argument which can be strengthened through additional repetition".

Yes, the point is that semantics is important to objective truth. You seem to think that you can dismiss the problem by saying "that's just semantics". That doesn't make the issue go away, it's just a case of you finding an excuse to ignore it. — Metaphysician Undercover

You're focused on telling me how "the sun rises" is inherently a false statement when all I'm trying to discuss is the consistency of the observable phenomenon we all know and colloquially refer to as "the rising of the sun".

Models which predict reliably is not truth at all, it's predictability. As I've just demonstrated, the capacity to predict can hide profound falsity which lies beneath. Therefore the capacity to predict is really irrelevant to truth and falsity. Prediction is derived from conclusions of deductive logic. The truth or falsity of the conclusions depends on the truth or falsity of the premises. The premises may be derived from conclusions of inductive reasoning, but the truth or falsity of these inductive conclusions is an issue of semantics. Whether "the sun rises each morning", "water boils at 100 degrees Celsius and freezes at zero", "the sky is blue", are true or not, is an issue of semantics. — Metaphysician Undercover

Everytime you say "truth", somehow I think you're always referring to "ultimate and objective truth". Well what is that? Does it even exist? Can we ever refer to something as "true" and not be inherently stating a falsehood? I've been very clear from the beginning, in every single one of my posts, that "objective certainty" is not achievable. I've not been concerning myself with it or been discussing it at all since my first post or only to clarify that science and what we call "objective scientific fact" is not founded on deductive certainty, it is founded in inductive likelihood from consistency in observations and reliable predictions. It's a whole different kind of truth than the truth you continuously charge me with not recognizing that science does not produce.

Semantically, you framed an attack on the point I was making about the consistency of experiences and how this consistency serves as a logical foundation for empiricism and science by stating "It is false to say that the sun rises" in order to try and point out how there might be deeper truth to a given phenomenon which therefore renders the more superficial observable truth false.

Well... No. They don't necessarily render them false... The superficial induction based truths, if strong enough from the get go, tend to remain true, while the deeper truths, which are also founded in induction, provide additional explanatory and predictive power which the more superficial truths lack. The fact that the earth spins does not falsify the actual meaning of the statement "the sun rises" (not the misinterpretation you keep using as a straw man, which I have clarified many times thus far), it is what creates the cyclical phenomenon we observe to begin with. I don't need to know the earth is round, or that it spins, or that this is why the sun is visible and then not visible in order to experience and record one of it's effects ("sunrise"), or to use induction to reason that it this effect will likely continue happening.

You're basically using plato's allegory of the cave to try and convince me that my statements are "false" when all I'm trying to do is point out that the more consistently the shadows on the wall behave, the more reliably we are able to predict their future behavior. I'm pointing at consistency in the behavior of the shadows and you are saying broadly "you can never be certain of shadows", but I never said that we could be certain, I said that the more consistently these shadows behave the more confident we can be in predicting the future behavior of said shadows.

Hello to all, and welcome ... to my mind!

Th very terms objective and subjective are about framing our world view in a particular way. The objective is only known by the subject in a subjective way. I do not know anything objective, but I may know of something in an objectifying manner.

Generally it is about the "thingness".

Kant may be worth a mention in regards to his use of the terms "phenonemon" and "noumenon".

Personally I just jump straight a phenomenological position so the whole objective/subjective question simply dissolves.

If I think I am on fire and in pain then I still feel like I am burning even if objectively viewed by others they assume I am merely in the grip of psychosis. Their objective opinions are not really important here.

Kant knew that people didn't know what words mean, so his fav illusion was just renaming familiar things, rendering them unfamiliar to the children that never grasped them in the first place (he was the only adult in the world after all.. he supposed).

How can you really define the distinction between objective and subjective if we only ever are subjective. — intrapersona

By definition the term objective includes all subjective perceptions.
The only need for distinction is between a subjective belief and an objective truth.
Things can be objectively true irrespective of subjective beliefs.
That is to say the truth of objective states is not contingent upon any particular subjective belief about that state.

The objective world remains only ever an inference at best. — intrapersona

By definition the objective world is a brute fact.
There is no coherent way to logically found claims upon solipsism.

If you had charitably interpreted what I was saying, you would have acknowledged that my point was not to say or even imply that "the sun moves through the sky while the earth remains still", but instead that "whatever the sun does (or does not do), it does so with observable consistency, which can be the basis for an inductive argument which can be strengthened through additional repetition". — VagabondSpectre

The thread questions "objectivity". You seem to think that consistency in observation is synonymous with "objective". I've demonstrated that consistency in observation does not imply "truth". My claim is that since it doesn't imply truth, we should not consider this to be objectivity.

Now, you have provided no principle whereby we can proceed logically from consistency in observation to your claim of observable consistency. Do you see the difference? We have as evidence, consistency in observation. Consistency is a property of the observations, the descriptions, that's my point. How do you proceed to the conclusion that consistency is a property of the object, to claim "observable consistency"?

Everytime you say "truth", somehow I think you're always referring to "ultimate and objective truth". Well what is that? Does it even exist? Can we ever refer to something as "true" and not be inherently stating a falsehood? I've been very clear from the beginning, in every single one of my posts, that "objective certainty" is not achievable. I've not been concerning myself with it or been discussing it at all since my first post or only to clarify that science and what we call "objective scientific fact" is not founded on deductive certainty, it is founded in inductive likelihood from consistency in observations and reliable predictions. It's a whole different kind of truth than the truth you continuously charge me with not recognizing that science does not produce. — VagabondSpectre

The op deals with a difference between objectivity and subjectivity. Is it your claim now, that there is no such thing as objectivity? I think there is objectivity, but truth is essential to it.

The superficial induction based truths, if strong enough from the get go, tend to remain true, while the deeper truths, which are also founded in induction, provide additional explanatory and predictive power which the more superficial truths lack. — VagabondSpectre

OK, so how do we determine whether the superficial induction based conclusions are true or not? Let's take the sun rising example. Your claim was that no person would deny that the sun rises, and therefore it is true. I deny it, and have explained how it is clearly false.

The fact that the earth spins does not falsify the actual meaning of the statement "the sun rises..." — VagabondSpectre

Yes, it clearly does falsify the actual meaning of that statement. The sun is the subject. It is engaged in the activity of rising, according to the meaning of the statement. But clearly the sun is not involved in any such activity, the earth is the proper subject here, engaged in the activity of spinning. The sun rising is a false description of what is occurring. Why do you not accept the reality, that this is a false description? You want to give to "the sun rises", a metaphorical meaning, and claim that there is "truth" in this metaphorical meaning. But you haven't explained how there is truth in metaphor.

You're basically using plato's allegory of the cave to try and convince me that my statements are "false" when all I'm trying to do is point out that the more consistently the shadows on the wall behave, the more reliably we are able to predict their future behavior. I'm pointing at consistency in the behavior of the shadows and you are saying broadly "you can never be certain of shadows", but I never said that we could be certain, I said that the more consistently these shadows behave the more confident we can be in predicting the future behavior of said shadows. — VagabondSpectre

You're missing the point. What is consistent is the observations, the descriptions. You conclude that the shadows are behaving consistently because there is consistency in the descriptions. But that's not the case, the consistency is in the observations, the descriptions, not in the shadows being observed. Perhaps it's like the sun rising, the shadows are not doing anything at all, the human mind is active, making it appear like the shadows are active. Isn't this what eternalism says?

The thread questions "objectivity". You seem to think that consistency in observation is synonymous with "objective". I've demonstrated that consistency in observation does not imply "truth". My claim is that since it doesn't imply truth, we should not consider this to be objectivity. — Metaphysician Undercover

You know very well at this point what I think; consistency in observation gives rise to an inductive argument that is the basis for the whole of science. I have never said this amounts to "objective truth", I've been going well out of my way to define it thusly:

" I'm pointing at consistency in the behavior of the shadows and you are saying broadly "you can never be certain of shadows", but I never said that we could be certain, I said that the more consistently these shadows behave the more confident we can be in predicting the future behavior of said shadows. "

"Repeatable observations of reliable phenomenon assist in producing models which allow us to reliably predict various aspects of said phenomenon. It's not objective truth; it's reliable and useful truth; that's science. "

"It's the fact that things appear to remain consistent which persuades us that whatever we uncover about them through repeatable experimentation (predictions) and observation (regardless of whether that knowledge is objective certainty or not), is worth knowing." — Vagabond

Now, you have provided no principle whereby we can proceed logically from consistency in observation to your claim of observable consistency. Do you see the difference? We have as evidence, consistency in observation. Consistency is a property of the observations, the descriptions, that's my point. How do you proceed to the conclusion that consistency is a property of the object, to claim "observable consistency"? — Metaphysician Undercover

It does not actually matter whether or not consistency is a property of the object because as long as the observations themselves remain consistent then reliable predictions of future observations can possibly be based upon them. If I never have direct access to real things (instead only faulty and subjective observations) then why would I bother trying to say anything about the "real thing" in the first place? Maybe I'm just predicting future observations?

Science deals with the empirically accessible world and as such necessarily flows through "subjective observations".

The op deals with a difference between objectivity and subjectivity. Is it your claim now, that there is no such thing as objectivity? I think there is objectivity, but truth is essential to it. — Metaphysician Undercover

Here's the first thing I stated on page 1:

"There's no proof against solipsism; perhaps the thing of which we are most certain of is actually our own prevailing lack of absolute certainty." — vagabond

I'm not trying to substantiate science as ultimate and objective truth, I provided an answer but then I decided to provide more by answering the question: "If we have no direct access ultimate and objective truth, what is the next best thing we can access, or, how can we gain useful knowledge?

OK, so how do we determine whether the superficial induction based conclusions are true or not? Let's take the sun rising example. Your claim was that no person would deny that the sun rises, and therefore it is true. I deny it, and have explained how it is clearly false. — Metaphysician Undercover

Well, you denied an interpretation of "sunrise" which I have expressly identified as an incorrect interpretation of the position I originaly articulated. I never said that we live in a geocentric solar system, or that the earth remains motionless while the sun moves in order to create the day/night cycle. What I clarified my position to be was that "the sun appears over the horizon or appears to move across the sky. The word appears is how at first I tried to make it clear that I was referring to a phenomenon of "relative perspective" which occurs when a human is standing on the surface of the earth. The fact that the sun appears over the horizon does not contradict the earth's rotation, it is caused by it.

Yes you have defeated geocentrism, but you have not defeated "sunrise as an observable phenomenon" (as caused by the earth's rotation). How do you prove an observation? You can't. You can record it or make a similar observation in order to increase the inductive strength of an individual observation, but the observation itself must on some level just be accepted for what it is until contradictory observations come along. Knowing the rotational speed and axis of planets in conjunction with their orbits around a star allows us to predict "sunrise" (when the sun would appear over the horizon at a given geographical point) without ever having been there; the observations agree with the model you say contradicts them.

Yes, it clearly does falsify the actual meaning of that statement. The sun is the subject. It is engaged in the activity of rising, according to the meaning of the statement. But clearly the sun is not involved in any such activity, the earth is the proper subject here, engaged in the activity of spinning. The sun rising is a false description of what is occurring. Why do you not accept the reality, that this is a false description? You want to give to "the sun rises", a metaphorical meaning, and claim that there is "truth" in this metaphorical meaning. But you haven't explained how there is truth in metaphor. — Metaphysician Undercover

Well it's not metaphorical, it is a statement of perspective "from this perspective, the sun becomes visible at A time and at Y vector". It's an observation and repeatability is the source of it's strength.

You're missing the point. What is consistent is the observations, the descriptions. You conclude that the shadows are behaving consistently because there is consistency in the descriptions. But that's not the case, the consistency is in the observations, the descriptions, not in the shadows being observed. Perhaps it's like the sun rising, the shadows are not doing anything at all, the human mind is active, making it appear like the shadows are active. Isn't this what eternalism says? — Metaphysician Undercover

So now I cannot even observe the shadows!?!

Woah, bro... This is cave-ception:

"Imagine that you are in a dark cave and under physical restraints which force you to only ever be facing a single wall. A fire is lit behind you which casts shadows upon the wall in-front of you. You are also blindfolded, and so while you cannot see the shadows, all you can do is grope the wall in front of you, feeling for warmer and colder spots which might indicate where the firelight, or a shadow, has recently been lingering.

It's the warm and cold spots man; they're consistent. Every time I drop what I can only faultily describe as what I subjectively observe to be a "television" on my "foot", I am overwhelmed with a very particular feeling which happens to have a peculiarly rigid correlation with what I can only faultily describe to be what I subjectively observe as "significant damage to my physical body"....

we can see the shadows; that's the point of the metaphor.

---------

To summarize my intention in this thread, I sought to provide a useful alternative to objective certainly after having contested that we do not currently possess very much objective certainty, if any. One of the qualities we would expect objective truth to have is complete reliability (because it is true and unchanging or true at the time). The entire goal of the scientific method is to seek the most fundamentally reliable descriptions and models of phenomenon (those with explanatory or predictive power) that it can find as a way of attempting to either A: simulate or approximate or approach "objective truth", or B: produce reliable and useful "truth" (not the same thing, but still a very useful kind of truth none too less).

I never said that we can never access objective truth, or even that we can never be certain of it, just that right now we're certain of almost nothing. Science provides a useful answer to how we can improve what we "know", despite a lack of absolute certainty, by testing models against the consistency of our observations, experiments, and experiences. Science is limited by what we can empirically experience. That's a fact. Do you propose an alternative route which can certainly deliver us closer to absolute truth, or dare I say, upon it?

To summarize my intention in this thread, I sought to provide a useful alternative to objective certainly after having contested that we do not currently possess very much objective certainty, if any. — VagabondSpectre

I disagree.
We can be certain that solipsism is not the case.
Solipsism leads to an ill defined infinite regress that would not allow you to form any conclusions about the existence of anything (including yourself).
http://mathworld.wolfram.com/Self-Recursion.html
https://en.wikipedia.org/wiki/Infinite_regress

That is to say that if the term self is not distinct and mutually exclusive of the term not self, then there is no conclusion that you can draw what so ever.
This meany by definition the terms self and not self are independent of one another.

People don't seem to understand that we would not be able to make any sense out of anything if solipsism was true.
This is just a consequence of logic.
If you could only reference/access yourself (solipsism) then you would be stuck in an infinite loop of trying to define self by referring to self, by referring to self, by referring to self...ad infinitum.
But if a not self exists (objective reality), you can break the infinite cycle by reference self as that which is distinct from not self.

What I see people argue is this...
"The only thing we experience is our perceptions, therefor basis of our reality of is our perception."

That is fine if that is how you want to define terms but it is essentially a bare assertion about semantics and not an argument that demonstrates a point.

I say we have access to our subjective information which is nothing but objective information that has been processed by our brains.

I realize that this is not particularly interesting to think about, but the debate is really about semantics and is not that interesting in the first place.
I truly don't understand how people believe there is some profound philosophical dilemma here?!?
:-|

I disagree. We can be certain that solipsism is not the case. Solipsism leads to an ill defined infinite regress that would not allow you to form any conclusions about the existence of anything (including yourself).

http://mathworld.wolfram.com/Self-Recursion.html
https://en.wikipedia.org/wiki/Infinite_regress

That is to say that if the term self is not distinct and mutually exclusive of the term not self, then there is no conclusion that you can draw whatsoever.

This meany by definition the terms self and not self are independent of one another.

People don't seem to understand that we would not be able to make any sense out of anything if solipsism was true.

This is just a consequence of logic.

If you could only reference/access yourself (solipsism) then you would be stuck in an infinite loop of trying to define self by referring to self, by referring to self, by referring to self...ad infinitum.

But if a not self exists (objective reality), you can break the infinite cycle by reference self as that which is distinct from not self. — m-theory

In my mind, (heh),The problem of an ill defined infinite regress inherent in solipsism makes it more difficult for us to make sense of things or to be certain of them, but the dilemma of solipsism is not that it has much (if any) merit as a hypothetical model, it's rather that many of it's variations cannot be fully falsified or discounted as a possibility. When it comes to "things of which we are certain", I do not count the statement "solipsism is not true" to be among them.

What I see people argue is this...
"The only thing we experience is our perceptions, therefor basis of our reality of is our perception."

That is fine if that is how you want to define terms but it is essentially a bare assertion about semantics and not an argument that demonstrates a point.

I say we have access to our subjective information which is nothing but objective information that has been processed by our brains. — m-theory

Consider the brain in a vat scenario. A powerful scientist could be feeding impulses from a simulation into your brain in exactly the same way as if your brain was in a skull, rendering you unable to determine if the world you perceive actually extends beyond your potentially simulated or deceptive perceptions.

This isn't exactly full blown solipsism, but it establishes a primitive case which can cast some (albeit minimal) doubt on whether or not our perceptions even indirectly reflect an external or objective world.

Skepticism can really do away with a lot if it is applied to the extreme, but luckily pragmatism regularly steps in and sets us straight.

I realize that this is not particularly interesting to think about, but the debate is really about semantics and is not that interesting in the first place.

I truly don't understand how people believe there is some profound philosophical dilemma here?!?
:-| — m-theory

That's quite alright, your point is well on topic.

Solipsism is not really a profound philosophical dilemma, but it is a proper hard dilemma none the less. Whether or not I (you) live in a solipsistic world in the end would change nothing of consequence as far as our perceptions are concerned, so I (you) don't have any reason to waste much time trying to validate or falsify it.

Consider the brain in a vat scenario. A powerful scientist could be feeding impulses from a simulation into your brain in exactly the same way as if your brain was in a skull, rendering you unable to determine if the world you perceive actually extends beyond your potentially simulated or deceptive perceptions.

This isn't exactly full blown solipsism, but it establishes a primitive case which can cast some (albeit minimal) doubt on whether or not our perceptions even indirectly reflect an external or objective world.

Skepticism can really do away with a lot if it is applied to the extreme, but luckily pragmatism regularly steps in and sets us straight. — VagabondSpectre

Your brain in a vat example does not cast doubt on whether or not there is an external world. There is still the need for your "powerful scientist" feeding impulses. The scientist comprises an external world. It is just that in this example, the real external world is not anything like the external world as the brain in the vat perceives it.

That is what I've been arguing is really the case, the real external world isn't anything like the way that we perceive, and describe it. That is evident from the example which we've already discussed, "the sun rises". The description refers to what we perceive, but we now know that what we perceive is not anything like what is really the case. We could extend this to our understanding of substance in general, molecules and atoms etc., what we perceive is completely different from what is really the case. Since this extreme difference exists, between how we perceive, and describe, the external world, and what we've determined is really the case, it may just as well be a brain in the vat scenario. We still haven't gotten beyond analyzing the impulses, understanding them well enough, to the point of determining the necessity for a "powerful scientist" sending us these impulses.

How we've progressed in this discussion, you and I, has been painfully slow, because we each have vastly differing perspectives on this. You want to assume that consistency in observations implies necessarily that there is consistency in the external world, but we haven't accounted for the brain itself, which in this example is assumed to be in a vat. So let's start with a real skeptic's position, let's assume that it is possible that there is no scientist at all, absolutely nothing external, just a mind, and the mind itself is producing all the images of perception.

Notice that I introduce this premise as a possibility. This is to counter your assumption that consistency in observation necessarily implies consistency in the thing observed. If we allow that the mind itself is capable of creating, and this is what is implied by the concept of free will, that the mind can create without the necessity for external causation, then it is possible that the observed consistency is completely created by the mind.

This is the point which I've been attempting to bring to your attention. If we allow the principles of free will, we allow that the mind itself creates without external cause. So when we proceed to analyze consistency in observations, we need to be able to distinguish which aspects of that consistency are created by the mind, and which aspects are proper to the thing being observed.

This is why we need to consider semantics, the words which we use, and the ways in which we describe things, as having real influence over the observations which we make, and especially the consistencies which we observe. I say this because it is clear that we actually seek consistencies, as consistency is what leads to understanding, so we describe things in terms of consistency. But of all particular things, in general, there are differences and similarities between them. We may overlook the differences to focus on the similarities. And this is what happens with our habitual word use, we call things by the same name, because they are similar in some way, overlooking the differences, and this creates consistency. The use of the same word to describe different things creates an illusion of consistency, through overlooking the differences.

So for instance we say "the sun rises in the east". This is a statement of consistency. However, each day the sun will appear to come up in a slightly different location on the horizon. So the sun isn't consistently rising in the same place, directly to the east, it varies from south to north, despite the fact that we say it rises consistently in the east. We create a generalization, overlooking the various differences, and say that the sun rises in the east. Now we have a consistency which has been created by this generalization, which acts as a description of many slightly different occurrences, describing them all with the very same words, "the sun rises in the east". This consistency has been created by our mode of description, which is to overlook slight differences, and focus on similarities. However, overlooking the inconsistencies, to focus on the consistency, produces a false consistency. It is necessary to negate this false consistency "the sun rises in the east", and focus on all the slight inconsistencies, in order to truly understand the relationship between the earth and the sun.

You think pragmatism sets us straight, but that is not the case at all. Pragmatism is what inclines us to create consistencies, and in creating these consistencies the real inconsistencies are hidden. By loosing track of the real inconsistencies through the claim of consistency, misunderstanding thrives.

In my mind, (heh),The problem of an ill defined infinite regress inherent in solipsism makes it more difficult for us to make sense of things or to be certain of them, but the dilemma of solipsism is not that it has much (if any) merit as a hypothetical model, it's rather that many of it's variations cannot be fully falsified or discounted as a possibility. When it comes to "things of which we are certain", I do not count the statement "solipsism is not true" to be among them. — VagabondSpectre

That we can draw distinction from self and not self falsifies solipsism.
If solipsism was true we would not be able to form such a distinction because of the infinite regress problem.

Consider the brain in a vat scenario. A powerful scientist could be feeding impulses from a simulation into your brain in exactly the same way as if your brain was in a skull, rendering you unable to determine if the world you perceive actually extends beyond your potentially simulated or deceptive perceptions. — VagabondSpectre

The brain in the vat is not useful to your point as it takes for granted that an objective world does exist.
Again if objective information did not exist (that which is not self) then you would have no way to define self (form subjective perceptions).

This isn't exactly full blown solipsism, but it establishes a primitive case which can cast some (albeit minimal) doubt on whether or not our perceptions even indirectly reflect an external or objective world. — VagabondSpectre

Again it is rather simple.
In order to form any notion of self there must exist a not self distinct and independent from that self.
If in reality there were no such distinction then you would lapse into an ill defined infinite regress of self referencing self ad infinitum.

That this is not the case is proof that solipsism is not the case.

Solipsism is not really a profound philosophical dilemma, but it is a proper hard dilemma none the less. Whether or not I (you) live in a solipsistic world in the end would change nothing of consequence as far as our perceptions are concerned, so I (you) don't have any reason to waste much time trying to validate or falsify it. — VagabondSpectre

My point was that it is not a hard dilemma at all.
It is rather simple.
The debate is a semantic one.

Those that argue doubt of the existence of not self as distinct and independent are merely arguing that we redefine terms to entertain a philosophical dilemma where one does not exist.
That is to say there is no force of logic that it is necessary to redefine the terms self and not self such that these terms are not distinct and independent.
In fact it is not logically possible to construct such an argument because of infinite regress.

It is quite literally logically impossible to actually doubt the existence of the objective world (not self) without also doubting the existence of the subjective (self).

If the not self does not exist then it is logically impossible to define the self because of infinite regress.
If you assert that the subjective (self) does exist, the only logically founded way to reach this conclusion is by referencing the objective world (not self).
Exclusive access to only self reference does not allow one to draw a conclusion of the existence of self it leads to infinite regress and from ill defined terms.

So I balk notion that all one can be sure of is only the self (subjective perception).
This can only be true if are also sure of the not self (objective information).

There is no logical way to be sure of the existence of self otherwise?!?
:s

Those that are sure of self, subjective perception, or what ever you want to call it, are not solipsists.
This is why the position is incoherent.

The position asks that all you can be sure of as existing is the subjective (self) even while in order for that to be true it logically entails the existence of the objective (not self) as distinct and independent.

The position claims that we are ONLY sure of the existence of the subjective however, which is inconsistent logically.

In fact, from a foundation of logic, the opposite is the case.
We can only be sure of self if there is a definite distinct and independent not self.

I will grant that we may be subjectively wrong about what is the true state of objective existence, but what we cannot do is doubt that the objective exists in fact without also doubting that the subjective exists in fact.

You, perhaps hint at a true solipsist position.
If you claim we cannot be sure of the existence of the objective, then this logically entails that we are also not sure of the existence of the subjective.
These terms would be ill defined that there would be no distinction drawn between them.
That would be a consistent position at least, however you would nave no certainty about anything, subjective, objective or otherwise.

My response to this point is not only is that an unnecessary skeptical position, it is in fact logically impossible to prove that it is necessary.

Skepticism of about the existence of the objective is possible sure (granting that an infinite regress can be an actual occurance in reality) but just because it is possible does not make it necessary.

Again if it were not possible in reality to draw the distinction of not self and self then we would be stuck in an ill defined infinite regress in reality.
That is not the case at all, even those that argue the case for solipsism are claiming we can be sure of the existence of self, they simply fail to realize that this also logically entails the existence of some not self which is distinct and independent.

That is what I've been arguing is really the case, the real external world isn't anything like the way that we perceive, and describe it. That is evident from the example which we've already discussed, "the sun rises". The description refers to what we perceive, but we now know that what we perceive is not anything like what is really the case. We could extend this to our understanding of substance in general, molecules and atoms etc., what we perceive is completely different from what is really the case. Since this extreme difference exists, between how we perceive, and describe, the external world, and what we've determined is really the case, it may just as well be a brain in the vat scenario. We still haven't gotten beyond analyzing the impulses, understanding them well enough, to the point of determining the necessity for a "powerful scientist" sending us these impulses. — Metaphysician Undercover

The brain in a vat scenario is useful to show that it could be the case that the sun (let alone sunrise), molecules, and atoms do not reflect or represent a true external reality, but it does not prove it to be the case.

I disagree that the term "sunrise" makes it evident that the real external world isn't anything like the way we perceive or describe it. People concluding geocentrism as a result of observing the obscured and then not obscured visibility of the sun at a particular point on the visible horizon shows how sometimes perception CAN be misleading, but nothing we have yet discovered through reason or science suggests that the observation or experience we colloquially refer to as "sunrise" is an illusion, or a farce, or inherently not reflecting of a true external reality. Further astronomical discoveries beyond "I can see the sun" (sunrise) have enhanced our understanding of the phenomenon, not invalidated the phenomenon itself or shown to be not real. Knowing the orbit and rotation and wobble of the earth can allow us to predict with approximate certainty exactly when and where sunrise will occur (throughout the past and into the foreseeable future). A round rotating Earth and a heliocentric model necessitates that sunrise occur (unless the axis of rotation were pointing directly at the sun at all times).

What is evident from the apparent falsity of geocentrism is that our perceptions can be falliable, but this does not mean that there might be some truth or objectivity contained in our perceptions. Take the heliocentric model for instance, do you think that whatever the sun is (or atoms, or gravity, or time, etc...) that if we were able to get down to "the true external world" that there would not be some fundamental "first principle" which gives rise to the corresponding phenomenon we experience on our end? Yes we could be a brain in a vat, and our perceptions necessarily deceptive, but we also might not be a brain in a vat, and whatever creates the sun (and sunrise, and everything), might be indirectly perceptible through observation, experiment, and induction.

You're willing to say that geocentrism is clearly false because heliocentrism has greater explanatory or predictive power (it's supporting evidence), so what makes you then so quick to assert that heliocentrism is equally as false?

You want to assume that consistency in observations implies necessarily that there is consistency in the external world. So let's start with a real skeptic's position, let's assume that it is possible that there is no scientist at all, absolutely nothing external, just a mind, and the mind itself is producing all the images of perception.

Notice that I introduce this premise as a possibility. This is to counter your assumption that consistency in observation necessarily implies consistency in the thing observed. If we allow that the mind itself is capable of creating, and this is what is implied by the concept of free will, that the mind can create without the necessity for external causation, then it is possible that the observed consistency is completely created by the mind. — Metaphysician Undercover

I'm not saying it "necessarily implies" consistency, but instead "infers via induction", but really there's several points caught up in this statement.

First and foremost I'm asserting that "reliable and useful predictive power" can be found through inductive ("cumulative") arguments which are at their base founded on verifiable or repeatable observations. Basing models on reliable phenomenon (i.e: repeatable; having a pattern) is a way to approximate or simulate the strength of "objective truth". Objective truth hypothetically would be 100% reliable and always remain 100% consistent. Given that we can never be certain what we know "objectively reflects the true external world", inductive logic in this form serves as a pragmatic alternative to seeking out more "truth". Even though it is "approximate truth" rather than "objective truth" we can still make inductively gathered truths stronger and stronger through additional experimental rigor and through the expansion of more and more congruent explanatory and predictive models in order to simulate or approximate as best we can the consistency that we imagine objective truth ought to have.

The above position is thoroughly defensible, but what is slightly less defensible (as is directly derived from the above position) is the second position that seems to be getting caught up in our discussion: whether or not our perceptions can or do contain some semblance of information that can be said to "be something like the true external world" (as opposed to your position "it is evident the true external world is nothing like our perceptions"). While using induction to come to highly reliable and consistent explanations simulates some of the power we reckon an "objectively true explanation" might have (consistency and reliability), we can never use it to be absolutely certain it's "truth" may never one day be shown to be inconsistent or inaccurate, like geocentrism.

It is possible that the body of science is on a path toward closing in on or approximating actual universal first principles, but it is also possible that the first principles science might be closing in on are just the deceptive or abstract rules of an evil scientist's simulation. Either way my point is quite simply that induction, especially with respect to the scientific method and it's current body of knowledge, can produce "truths" so reliable that for practical reasons we might behave as if they are objectively true.

This is the point which I've been attempting to bring to your attention. If we allow the principles of free will, we allow that the mind itself creates without external cause. So when we proceed to analyze consistency in observations, we need to be able to distinguish which aspects of that consistency are created by the mind, and which aspects are proper to the thing being observed. — Metaphysician Undercover

Even if my mind creates everything I experience, there can still be consistency in my observations. Whether or not my perception of something (a shadow I mistake for a person for instance) is actually a perception created by my mind might not alter the fact that I consistently observe or perceive it. Even though I may totally misunderstand what something is, I can still observe it (and misunderstand it) consistently. If past observations (despite a prevailing misunderstanding) are more and more consistent, the predictions of future observations (despite the same prevailing misunderstanding) become inductively stronger and stronger. Even if solipsism is true, some observations I make of the fictitious world I create for myself have peculiar consistency with one another, which leads me to guess that either I imagine things with consistency or there is some underlying mechanism which generates that consistency. In either case the observations themselves have consistency.

You think pragmatism sets us straight, but that is not the case at all. Pragmatism is what inclines us to create consistencies, and in creating these consistencies the real inconsistencies are hidden. By loosing track of the real inconsistencies through the claim of consistency, misunderstanding thrives. — Metaphysician Undercover

Science constantly improves by reducing the inherent "inconsistency" or inaccuracy of explanatory gap in it's various interwoven models. This is why you are so confident that geocentrism masks inherent inconsistency and generates a false model by focusing too much on overt consistency; heliocentrism came along and provided more accuracy and even in a more simplified format. The reason why science works is because it sheds obsolete models for one's which better account for apparent inconsistencies in the explanatory and predictive power of existing models, thus "approximating" "reliable truth".

It might all be my imagination, but cumulative induction and the scientific method in general works.

In order to form any notion of self there must exist a not self distinct and independent from that self.

If in reality there were no such distinction then you would lapse into an ill defined infinite regress of self referencing self ad infinitum. — m-theory

What if the things which I perceive of as "not-self" are actually just works of fiction from my subconscious with no actual continuous existence beyond me imagining myself interacting with them or my subconscious mind temporarily simulating them in my conscious experience?

In this case it would still be coherent to say "not-self" and solipsism hold true.

@ the OP... Ever looked into Absurdism? As I understand it, it acknowledges that we're living in a confusing universe, but it also asserts we can choose to enjoy it anyway.

People concluding geocentrism as a result of observing the obscured and then not obscured visibility of the sun at a particular point on the visible horizon shows how sometimes perception CAN be misleading, but nothing we have yet discovered through reason or science suggests that the observation or experience we colloquially refer to as "sunrise" is an illusion, or a farce, or inherently not reflecting of a true external reality. — VagabondSpectre

That's the whole point though, what we see as "the sun rising" is not a true external reality. You keep insisting that it is, refusing to face the reality of the situation. The sun does not rise, despite the fact that we see the sun rising. I would like it if you could create in your mind, a better imaginary model, so that you do not see the sun rising anymore. Tell yourself that the sun is staying still. Then imagine what is happening without getting dizzy. What science has demonstrated very clearly to us, is that we do not perceive the external reality the way that it truly is. We do not perceive molecules, or atoms, or sub-atomic particles. Sure, you might argue that we taste and smell molecules, but we don't, we taste tastes, and smell smells. Let's face the facts, the way that we perceive things is not the way that they are, according to what science tells us.

You're willing to say that geocentrism is clearly false because heliocentrism has greater explanatory or predictive power (it's supporting evidence), so what makes you then so quick to assert that heliocentrism is equally as false? — VagabondSpectre

It's not predictive power which makes me prefer heliocentrism. As I explained, prediction is based in recognizing consistencies, and geocentrism had great predictive power as well. What heliocentrism gives us is the capacity to understand many inconsistencies. The reason why I believe that heliocentrism is still false is that there are many inconsistencies which persist. There are inconsistencies in our understandings of space, time, electromagnetism, and such things. Further, when I go outside in the morning, I can feel the sun touch me with its warmth. And as much as our sense perceptions may be inaccurate, touch, as a fundamental feeling, is fairly reliable. So I do not believe that there is space between the sun and myself. Just like we talk about space between you and I, I know there is not space there, there is air, I can feel it on my face, and the air is the earth's atmosphere, part of the earth. Likewise, we talk about space being between us and the sun, but that's not space, it's the sun's atmosphere, or field or something. So just like I am within the earth, being in its atmosphere, I am also within the sun, being within its field, or some such thing.

Even if my mind creates everything I experience, there can still be consistency in my observations. Whether or not my perception of something (a shadow I mistake for a person for instance) is actually a perception created by my mind might not alter the fact that I consistently observe or perceive it. Even though I may totally misunderstand what something is, I can still observe it (and misunderstand it) consistently. — VagabondSpectre

Yes, this is the point I was trying to make, our minds could be creating all the consistency which we observe. In this case, the consistency would not be within "it", the thing being observed, it would be within the mind only. The thing being observed would be totally inconsistent, but the mind is making it appear to be consistent. Do you believe that this is possible?

In either case the observations themselves have consistency. — VagabondSpectre

This might be true, but do you not see a big difference between "there is consistency in the thing being observed", and, "there is no consistency in the thing being observed, but my mind is creating the appearance of consistency"?

If past observations (despite a prevailing misunderstanding) are more and more consistent, the predictions of future observations (despite the same prevailing misunderstanding) become inductively stronger and stronger. — VagabondSpectre

So this is the problem I was referring to earlier. The observations become more consistent, the predictions become more reliable, but the misunderstanding remains. The problem is that the misunderstanding becomes stronger and stronger, because the reliability of the predictions creates the illusion that there is no misunderstanding, that all is understood. Then we do not bother to doubt this, what is perceived as an understanding but is really a misunderstanding, because the predictions are so reliable, that we don't even think that it might be a misunderstanding.

That's the whole point though, what we see as "the sun rising" is not a true external reality. You keep insisting that it is, refusing to face the reality of the situation. The sun does not rise, despite the fact that we see the sun rising. — Metaphysician Undercover

I've clarified more times than I care to count that the term "sunrise" as I have employed it should be taken to mean strictly: "The sun's visibility was obstructed by the Earth, then not obstructed".

You keep saying the sun doesn't rise like it's somehow going to convince me that the visibility of the sun has nothing to do with "external reality". I'm not talking about the sun "rising", I'm talking about it's visibility; your argument applies only to the straw-man of geocentrism that you feel the term "sunrise" necessarily entails, which even if it were the case I have already clarified my own position.

What science has demonstrated very clearly to us, is that we do not perceive the external reality the way that it truly is. We do not perceive molecules, or atoms, or sub-atomic particles. Sure, you might argue that we taste and smell molecules, but we don't, we taste tastes, and smell smells. Let's face the facts, the way that we perceive things is not the way that they are, according to what science tells us. — Metaphysician Undercover

But we do perceive atoms, and molecules, and heliocentrism too. We perceive them through processes of observation, prediction, and experimentation; induction. If we could not (or "do not") perceive atoms, why do you think they exist, how did we ever find out about them?

If you can only perceive that the sun moves through the sky, why do you think it does not? "Perceptions" can extend beyond raw and uninterpreted sensory data you know...

Taste and smell are abstract, sure, but they still might indirectly perceive something real. Taste buds on your tongue react in specific ways to specific molecules that come into contact with them. The way something tastes may in fact contain some real data about the thing being tasted; taste has some degree of consistency within individuals and between them which indicates the phenomenon of taste is not completely random in addition to being abstract. Eyeballs react to light, presumably real light which emanates from real things. When light bounces off of something and then enters our eyes we can recognize a change in the light (via the eyeball mechanism) which we presume reflects data contained in the object reflecting the light. "Redness" might be an abstract visual experience, but we're pretty damn sure that red light is a certain portion of the complete light spectrum, and that when full spectrum light bounces off an object and we see red, that this means the surface of that object is absorbing all visible light except for the red part which gets reflected.

Science is inevitably based in perception, so when you say "Science tells us that the way we perceive things is not anything like the way they really are", what you're really saying is "Our perceptions tell us that our perceptions are wrong", which is merely to say "I doubt perceptions". However, falsifying one perception with another more refined perception (the act and product of science?) can never be used to deductively falsify the whole of perception and experience altogether because using the supposed truth of perception ("science tells us") to establish the falsehood of all perceptions ("our perceptions are nothing like the way the external world is") is an invalid argument where it's conclusion contradicts it's premise. If perceptions can never be anything like the external world, then science (based in perception) can never rationally be used to come in and provide evidence or proof that our perceptions are nothing like the external world.

It's not predictive power which makes me prefer heliocentrism. As I explained, prediction is based in recognizing consistencies, and geocentrism had great predictive power as well. What heliocentrism gives us is the capacity to understand many inconsistencies. The reason why I believe that heliocentrism is still false is that there are many inconsistencies which persist. There are inconsistencies in our understandings of space, time, electromagnetism, and such things. Further, when I go outside in the morning, I can feel the sun touch me with its warmth. And as much as our sense perceptions may be inaccurate, touch, as a fundamental feeling, is fairly reliable. So I do not believe that there is space between the sun and myself. Just like we talk about space between you and I, I know there is not space there, there is air, I can feel it on my face, and the air is the earth's atmosphere, part of the earth. Likewise, we talk about space being between us and the sun, but that's not space, it's the sun's atmosphere, or field or something. So just like I am within the earth, being in its atmosphere, I am also within the sun, being within its field, or some such thing. — Metaphysician Undercover

Long story short you appeal to heliocentrism to falsify geocentrism because it has more predictive power. Why you believe heliocentrism is false is completely beyond me. Do you believe the sun even exists?

Yes, this is the point I was trying to make, our minds could be creating all the consistency which we observe. In this case, the consistency would not be within "it", the thing being observed, it would be within the mind only. The thing being observed would be totally inconsistent, but the mind is making it appear to be consistent. Do you believe that this is possible? — Metaphysician Undercover

It is possible although it seems unlikely. This is what I meant by "We cannot defeat solipsism".

This might be true, but do you not see a big difference between "there is consistency in the thing being observed", and, "there is no consistency in the thing being observed, but my mind is creating the appearance of consistency"? — Metaphysician Undercover

I see the difference but if my mind is creating extreme amounts of consistency then pragmatically I ought to behave accordingly (I.E: not dropping T.Vs on my foot).

So this is the problem I was referring to earlier. The observations become more consistent, the predictions become more reliable, but the misunderstanding remains. The problem is that the misunderstanding becomes stronger and stronger, because the reliability of the predictions creates the illusion that there is no misunderstanding, that all is understood. Then we do not bother to doubt this, what is perceived as an understanding but is really a misunderstanding, because the predictions are so reliable, that we don't even think that it might be a misunderstanding. — Metaphysician Undercover

As the predictions get stronger, the model gets more useful (generally) this is not contestable.

If predictive power plateaus, maybe this is because a theory is beginning to closely approximate whatever aspect of the external world it presupposes to model; maybe it has reached maximum predictive power. OR, maybe the theory has a fundamental flaw within it which inherently bottlenecks it's precision or accuracy. All of our current scientific theories might be entirely wrong, but the likelihood that of all our scientific theories none of them reflect anything fundamentally true, if however incomplete, about the external world, seems extremely low. Furthermore, when a new theory eclipses and makes obsolete an old one, this gives us even stronger inductive reasoning that the new theory contains some or more real data about the external world; it has greater predictive power and greater explanatory power; more useful.

We cannot yet say anything certain except this very sentence.

You're worried that we're basing everything off of fundamental misunderstandings, and that's fine, maybe we are, but you're also presuming (at least by your language) that this is in fact the case; that everything we believe and perceive is nothing like the way the external world is... This can be based on a weak inductive argument at best, and even if it were true would seem like useless knowledge when contrasted with traditional science. Yet you then you go even further: When I use Plato's allegory of the cave and begin talking about the shadows on the wall (which is a metaphor for our perceptions and how they not directly derived from the external world and hence amorphous and fallible), you even questioned those, claiming that even the things my perceptions are based on have nothing to do with the way the external world actually works. By your logic, "the external world" has infinite layers of complexity such that no matter how much we refine our perceptions we can not get any closer whatsoever to getting our hands on any real data about any real universe. No actual ultimate truth can possibly exist in such a universe.

What if the things which I perceive of as "not-self" are actually just works of fiction from my subconscious with no actual continuous existence beyond me imagining myself interacting with them or my subconscious mind temporarily simulating them in my conscious experience? — VagabondSpectre

Assuming that the reality was that there was no distinction from self and not self would leave you in an ill defined infinite regressing loop from which no conclusions could be drawn.
The process of defining self or not self would never end.

In this case it would still be coherent to say "not-self" and solipsism hold true. — VagabondSpectre

There is no logically consistent way to hold that solipsism is true.
If solipsism is true, in reality, then in reality we would not be certain of anything because we would be stuck in an infinite regress problem.

To say that "We can only be certain of the existence of self" is incorrect.
If we can be certain of self this is only true from a distinction of not-self which exist independent from that self.
If we cannot be certain of a distinct and independent not self, then nor will we have any certainty about self as a consequence.

From a logical standpoint the subjective world necessarily entails an objective world.

If we cannot be certain of one then by definition we cannot have certainty about the other.

A true solipsist would be an epistemological nihilist and assert that we could be sure of nothing at all.
And that statement itself would be something about which we could not be sure of.

This is why you cannot have any epistemological foundation with nihilism or solipsism.
The assertion "All things are uncertain" is itself an uncertain claim that regresses infinitely before it can ever reach a true or false conclusion.

It is all really quite simple and it boggles my mind that people are enamored with this non-dilemma.

If you are an epistemological nihilist/solipsist I say to you, well that position is not, and cannot be, logically grounded.
You have no and can have no foundation with which to support that assumption.

It is a non-starting point for philosophical inquiry.

From a logical standpoint the subjective world necessarily entails an objective world.

If we cannot be certain of one then by definition we cannot have certainty about the other.

A true solipsist would be an epistemological nihilist and assert that we could be sure of nothing at all.
And that statement itself would be something about which we could not be sure of.

This is why you cannot have any epistemological foundation with nihilism or solipsism.
The assertion "All things are uncertain" is itself an uncertain claim that regresses infinitely before it can ever reach a true or false conclusion. — m-theory

I'm not exactly sure why solipsism is impossible as you describe it.

As far as I can tell you say that "not-self" would be incoherent if solipsism were true, and since "not-self" is coherent, solipsism must be untrue.

I also do not understand why being uncertain that "not-self" exists means we must also be uncertain that "self" exists.

I understand why something like "an orange" cannot be coherently defined unless we can say "not an orange", but in solipsism "self" is construed to represent the fundamental source of everything that exists. It becomes a matter of equivocation to argue that since we casually experience "not-self" solipsism results in incoherency because "self" under solipsism refers to the fundamental source of everything, not the way we interpret our casual experiences.

Perhaps I should amend my hard position though; the thing we are most certain of, aside from perhaps our own existence (cogito ergo sum), is our overall prevailing lack of certainty.

P.S, I'm somewhat less than enamored with solipsism as a hypothesis of any merit or utility than you might think, however since I cannot deliver a proof that it solipsism is certainly not the case, I admit that I cannot fully defeat it.

The issue as I see it is that for the posits of solipsism, or even any sort of idealism, to make sense, we have to posit the realist view of there being creatures with minds as well as other sorts of things, stuff external to creatures with minds, stuff that creatures with minds can perceive, and so on. That's the only way we can even get to contemplating how our perception works, whether we can know anything but our own minds, and so on. If we were to truly reject that picture, there wouldn't be any issues of this sort whatsoever. There would just be the phenomena there is, and we wouldn't wonder what its relation was to us--there would be no "that stuff" in distinction to ourselves. It would all just be phenomena and that's it .

So solipsism and idealism only make sense in the first place by thinking about how minds work in the context of the realist framework.

There are more than a few variations of solipsism, and not all of them reduce "the other" into incoherence.

A kind of hard solipsism would be "Only my mind exists and the other people and things I perceive are created by my mind, and have no continuous or necessary existence beyond my perceptions of them".

With this kind of solipsism there is no guarantee that a fundamental way to "make sense" of how "minds" work is available in the first place. Living pragmatically would be greatly hindered by going around and treating "the other" as if it's existence is dependent on one's own mind (i.e "not real"), but the fact that we would be left in a very confusing situation (having no obvious or necessary way to determine how or why we experience what we experience) does not negate it as a possibility. It would change nothing from the perspective of a pragmatist, but this also gives no necessary indication that hard solipsism definitely is not the case.

A weaker form of solipsism posits that the only thing we can be certain of are the goings-on of our own mind, and points out that the realist approach involves several presumptions that cannot be proven or falsified. This kind of solipsism most closely tracks with the main question of this thread. It is in essence strong skepticism applied to the nature (or "truth") of our perceptions, which reduces what is "certain" to something like Descartes "cogito ergo sum" or something not dissimilar.

Out of the hard solipsist position stems a rather useless worldview, but out of the weaker version of solipsism stems several positions that do in fact have some merit. Descartes was right to apply skepticism for the sake of applying skepticism (in pursuit of something unquestionable; something certain), and out of it came a very sensical hierarchy of epistemological foundations. Our own existence is not questionable (per Decartes), but our senses and perceptions are highly fallible and so must be questioned and tested using apriori reasoning and confirmation and re-confirmation (for precision and accuracy) of actual empirical evidence.

The possibility that we might be a brain in a vat is enough to provide some doubt that the "the objective world is subjective" (or at least arbitrary in the sense that it may not reflect the "external world" of the scientist). This is is not a useful position to wield, but confronting it can be a useful exercise which forces us to improve as best we can the epistemic foundations that we base what we call "knowledge" on.

Again, none of those scenarios would make any sense if one didn't posit the realist picture in the first place.

I don't understand why "makes sense" from a human perspective is is presumed to be an inherent quality of "objective reality"...

Furthermore, the scenarios do seem to "make sense" to me. Are you suggesting that the world cannot be such that I am not something with continuous existence beyond your perceptions of me?

I don't understand why "makes sense" from a human perspective is is presumed to be an inherent quality of "objective reality"... — VagabondSpectre

I'm not saying anything like that. What I'm saying I'll explain again in the context of a response to:

Furthermore, the scenarios do seem to "make sense" to me. Are you suggesting that the world cannot be such that I am not something with continuous existence beyond your perceptions of me? — VagabondSpectre

They make sense to me, too, but because they were all framed within a realist picture of the world. What I said was that solipsism can't be made any sense of outside of a context of a realist picture of the world--which is how you presented your scenarios, but by framing it in those contexts, one necessarily undermines solipsism. If either ontological or epistemological solipsism are true, then that realist picture of what the world is like shouldn't make sense--because in both cases (ontological and epistemological solipsism) you can't know that realist picture. If any brand of solipsism is true, one can't know minds versus other sorts of things in the first place.

solipsism can't be made any sense of outside of a context of a realist picture of the world--which is how you presented your scenarios, but by framing it in those contexts, one necessarily undermines solipsism. If either ontological or epistemological solipsism are true, then that realist picture of what the world is like shouldn't make sense--because in both cases (ontological and epistemological solipsism) you can't know that realist picture. If any brand of solipsism is true, one can't know minds versus other sorts of things in the first place. — Terrapin Station

I understand what you mean by saying that a realist framework (i.e "the other" pragmatically and semantically exists (per prevailing perception)) is required for us to categorize and interact successfully (pragmatically) with the phenomena within the realm of our experiences. But even if hard solipsism were true there might still be consistency in our experiences, whatever they may be. As such, from our perspective of limited understanding, a realist framework could be entirely useful and perhaps the only way we can make sense of the world, but it could still be a misrepresentation of what is objectively real (as some here in this thread would gladly contend).

The fact that we have to inexorably conduct our affairs from within the construct and confines of what we all axiomatically accept to be "real" means that for an idea or understanding to have any utility it must refer to "real" things, but this is an issue only with utility, not "external objective truth" (or lack thereof). This may inductively undermine solipsism on many levels (aside from outright negating it's utility), but it does not deductively establish solipsism to be an impossibility, which is the only tired point I've really been defending.

Solipsism can be used as a skeptical tool - a hypothetical - to paint limits on the knowability of objective truth, especially as it relates to varying degrees of certainty. It's not a useful worldview outside of this context and I'm not suggesting anyone ought to wield it as an actual position, but I'm contending that we cannot actually discount many varieties of solipsism as certainly false.

I understand what you mean by saying that a realist framework (i.e "the other" pragmatically and semantically exists (per prevailing perception)) is required for us to categorize and interact successfully (pragmatically) with the phenomena within the realm of our experiences. — VagabondSpectre

It's not just that, it's that the very idea that some of the phenomena one experiences is mind and some is not mind is realist in nature, and solipsism doesn't make any sense as a concept if we don't accept that picture. We can't wonder if everything isn't just our mind or if we can't only know our mind if we're not assuming that the world is divided into mind and other stuff. Outside of that realist picture, there would only be the phenomena there is, and there would be absolutely no reason to wonder what our relationship to any of that phenomena is, there would be absolutely no reason to wonder about certainty--after all, what else could any of it be (or what else could we possibly know it to be) except the phenomena that it is under that scenario? There would be no other possibility for what that phenomena could be (or what we could know it as) other than what it is as phenomena.

So as a skeptical tool, if we assume solipsism, we have no skepticism whatsoever. We'd be certain of everything, and there would be no mind/other stuff cleavage, which wouldn't be solipsism after all.

So as a skeptical tool, if we assume solipsism, we have no skepticism whatsoever. We'd be certain of everything, and there would be no mind/other stuff cleavage, which wouldn't be solipsism after all. — Terrapin Station

Keep in mind I'm saying we should not give consideration to solipsism beyond the hypothetical; we should not assume it.

You say that if solipsism were true we would have no reason to wonder about relationships between experienced phenomena or degrees of certainty. Why? I understand that we have to live in a real world, but solipsism might not so much about establishing that direct experiences are unreal (to the point that we need not address them?) so much as an explanation of the source of all experienced phenomenon (and by extension a description of their underlying true nature). From within one possible experience of solipsism, what is perceivably one's own "mind" could be limited such that it simulates what we now experience as "the other" even though it if is somehow generated by or subject to deeper aspects of one's own mind (i.e subconsciousness?).

Your arguments completely ruin the utility of solipsism as a functional worldview, and I completely agree with that conclusion, but in my view a solipsist would disagree that we would have no skepticism, or be certain of everything. In their view understanding what they falsely perceive as "the other" by whatever means of inquiry available would be seen as the process of discovering more about their own mind.

I submit the following questions: "Are you certain you're not a brain in a vat à la Decartes? If so how? If not, presuming that you are in fact a brain in a vat, could you ever be certain of that, if anything? Would skepticism be useless from your perspective? Skepticism could in fact be what leads you to currently surmise that you are a brain in a vat in the first place, could it not?".

I submit the following questions: "Are you certain you're not a brain in a vat à la Decartes? If so how? If not, presuming that you are in fact a brain in a vat, could you ever be certain of that, if anything? Would skepticism be useless from your perspective? Skepticism could in fact be what leads you to currently surmise that you are a brain in a vat in the first place, could it not?". — VagabondSpectre

Well, keep in mind that I'm a realist first off, and with respect to philosophy of perception, I'm a naive or "direct" realist.

I thought I mentioned earlier (although maybe I just intended to do so but didn't get around to it, haha) that I see wondering about certainty as a misplaced concern. I agree with the philosophy of science/science methodology mantra that empirical claims are not provable, period. So certainty simply can't be had for any empirical claim, and it's not worth worrying about. What matters on my view are the reasons we have for believing one possibility over another.

Not all potential claims are equal. Some only have possibility going for them. For those claims the contradictory claim is almost always a possibility, too. (For example, "We're brains in vats." Well, "We're not brains in vats" is possible, too.) So possibility is never sufficient for belief. There have to be other reasons to believe whatever we do, and certainty isn't something to bother with, because it can't be had (for empirical claims, that is; logical claims are another matter).

So from my perspective, as a realist, skepticism isn't useless, but for a skeptical alternative to be worth consideration, there need to be reasons beyond possibility that it might be true. Thus, if soemone suggests "We might be brains in vats," the first thing I think is, "Okay, but why would we believe that?" There would need to be reasons to believe it--some sort of evidence, primarily, beyond the mere possibility of it, otherwise it's not worth bothering with.

As far as I can tell you say that "not-self" would be incoherent if solipsism were true, and since "not-self" is coherent, solipsism must be untrue. — VagabondSpectre

Both the self and not-self would be incoherent if solipsism was true because of infinite self referencing.
http://mathworld.wolfram.com/Self-Recursion.html
You can't define these things using self as the only reference point.
If you do use only self and then try to reference the self, you create an infinite regress that never defines the term self, or any other term for that matter.
That is not what happens when we try to define ourselves.
At least not to me.
I can define myself and reach the conclusion that I exist without an infinite regress problem.
That should not be possible if solipsism is true.

I also do not understand why being uncertain that "not-self" exists means we must also be uncertain that "self" exists. — VagabondSpectre

Because the only logically coherent way to define self is as something which is distinct and independent from not self.

If you only use self reference to define self you don't get any clear definition of self or not-self.
You get an infinite loop of self reference with no conclusions.

I understand why something like "an orange" cannot be coherently defined unless we can say "not an orange", but in solipsism "self" is construed to represent the fundamental source of everything that exists. It becomes a matter of equivocation to argue that since we casually experience "not-self" solipsism results in incoherency because "self" under solipsism refers to the fundamental source of everything, not the way we interpret our casual experiences. — VagabondSpectre

It is a logic thing.
You can never define the self in the first place using only self reference.
The only way to clearly define self that is logically consistent and does not fall prey to infinite regress is by introducing the not-self as a thing which must exist independent and distinct from the self.

Perhaps I should amend my hard position though; the thing we are most certain of, aside from perhaps our own existence (cogito ergo sum), is our overall prevailing lack of certainty. — VagabondSpectre

You did not have a hard position you have an inconsistent one.
If you claim you can be certain that the self exists this logically entails that we can be certain that the not-self exists independent and distinct from the self.

Other wise you run into the infinite regress problem in the link that stems from self reference.
If all you have is self referenece as your foundational starting point you can arrive at no logical conclusions what so ever.
That means you would not be sure the not-self exists, and you could not be sure that the self exists either.
There would be an infinite amount of steps trying to reach any conclusion.
That is not what happens in reality, so we can be quite sure the solipsism is false.

In reality we are not trapped in an infinite loop of self reference, in reality we can reach logical conclusions.
This is mutually exclusive of the possibility of solipsism being the true reality.

Its really quite simple.

P.S, I'm somewhat less than enamored with solipsism as a hypothesis of any merit or utility than you might think, however since I cannot deliver a proof that it solipsism is certainly not the case, I admit that I cannot fully defeat it. — VagabondSpectre

This is where you are wrong.
The proof that solipsism is not the case is the fact that we are not trapped in an infinite regress and we can arrive at conclusions.
This is only possible if solipsism is not true.

So from my perspective, as a realist, skepticism isn't useless, but for a skeptical alternative to be worth consideration, there need to be reasons beyond possibility that it might be true. Thus, if someone suggests "We might be brains in vats," the first thing I think is, "Okay, but why would we believe that?" There would need to be reasons to believe it--some sort of evidence, primarily, beyond the mere possibility of it, otherwise it's not worth bothering with. — Terrapin Station

I'm totally with you there. I don't hold solipsism as a belief nor would I advocate that anyone should. As a skeptical tool the fact that it could be true is used as a quick and dirty way to establish some degree of doubt (albeit a very small degree) to contrast against and weaken some notions of "complete/objective certainty". It's useless outside of an obscure and rather inconsequential lesson in epistemological limitations, and yet many find it an enduringly interesting thought experiment.

I must confess I'm having a hard time understanding the logic that you're using.

"Self" in the traditional sense (our discrete thoughts and experiences) is not the same as as the expanded definition of "self" (where it basically becomes "the source of everything") per some forms of solipsism. The connection between "self" and the "not-self" that we casually experience, per solipsism, is to do with the nature of the "not-self" being fundamentally different than the nature of the "self" (I.E, I am a mind that exists and you are just an impermanent illusion governed by my subconscious. Or, I am a brain in a vat but you are just fabricated electrical signals stimulating my brain and interpreted by me as another person).

Even a full blown metaphysical solipsist would not define other people as their own "self", they would merely say that other people have no fundamental or permanent existence akin to their own. This hard form of solipsism entails the presumption that nothing has permanent or tangible existence beyond what can be found within one's own ongoing experiences, but I do not see how or why linguistically referring to "not self", even in a metaphysically solipsistic existence, would actually create any logical issues of self-reference.