In an RGT thread, madnak and I get into it a bit on solipsism. Lets continue it here, for there are more people with actual knowledge/understanding of philosophy here (I have only a little as is fairly obvious).

Tao1;"Solipsism is untenable as an actual belief." (after snipping a big post on other matters)

madnak;"Solipsism is the most stable rational belief there is, and the only one that doesn't arbitrarily invoke unjustifiable premises about an external world."

Tao1;"What I meant was (and im tired so I fudged that up slightly, and might again) that it is not something to build a worldview on, nor knowledge. This is simply impossible by definition. Yes it is the most stable 'rational' belief that doesnt invoke unjustifiable premises. It is also useless.

edit: might be overreaching with the last, but ill let it stand. What I was trying to say was that it is useless to hold to solipsism when one is living. Might not be a bad position to hold that it is useless regardless though."

madnak;"My worldview is built on it, and is quite stable. You claim it's impossible, but you don't actually back up that claim and it doesn't seem that you've tried especially hard to form a solipsistic worldview.

As for "knowledge," either knowledge doesn't exist (and doesn't need to for any functional purpose), or knowledge can easily be constructed on a solipsistic worldview (depending on the epistemology you're looking to push, and your definition of "knowledge")."

Tao1;"Fair enough. I have been reading David Deutsch's the fabric of reality, specifically this passage. And have taken in with that, perhaps I do that too quickly. Everything I could say on it, I feel he has said better and obviously Ive taken the idea from there."

madnak;"Seems naive and circular to me. Virtually all of these objections can be addressed simply based on viewing the external as a model and not a "reality," considering sensations and perceptions as inexplicable inputs (and not "windows into absolute truth"), and acknowledging that "self" in the context of solipsism does not merely describe the current contents of consciousness.

Deutsch has no understanding of solipsism and may well have no exposure to the philosophy except in the caricatured form he presents here."

Tao1;"Perhaps I misunderstand, but that seems to me to no longer be solipsism. It seems to me that solipsism (effectively) denies all things outside of the brain as being real and autonomous.
Regardless, this is wavering very much offtopic, perhaps we should take this to smp?"

madnak;"Maybe so, it seems to be working its way into a lot of different threads."


So, here we are. Perhaps before we go on, we should get a clear definition of solipsism.

wiki: "Solipsism is the philosophical idea that one's own mind is all that exists."

There are likely definitions from better sources, if you have some to share, share them. Please comment if you're interested.

I'm pleased I wrote all this.

My madnak character speaks my truth.

It looks like there's a confusion similiar to that between strong and weak atheism. Maybe there's a strong and weak version of Solipsism. The difference between believing others don't exist and merely asserting that there are limits to what we can know and building a world view based strictly within those limits.

PairTheBoard

Solipsism in itself is not provable, but it doesn't try to hide the fact. It's really just "extreme rationalism" so if you want indepth explanations regarding it, the best discussion on the subject was made between continental rationalists and british empiricists in the late 1700s. Personally I would say the later german idealists (Kant in particular) joined rationalism and empiricism together as well as can be done, many people on this board tend to disagree.

But maybe the most important bit is that you can't really debate solipsism. It's a statement that is logically identically to "what I perceive is always the the mind of a small leprechaun". That is to say that the statement is always internally consistent, can't be measured and can't be disproven in any way. Rationally that makes it fine, empirically it makes it bogus.

Occam's Razor refutes Solipsism. DUCY?

/thread

Occam's razor doesn't really refute anything. It can tell you what model is preferable empirically, but it won't tell you which one is more true. Maybe more importantly; rationalism/solipsism is not based on empirical principle.

I should probably keep my mouth shut, but I didn't think OR could 'refute' anything. As far as I'm aware it's not a tool of verification as such. I give it about a 40% shot your post is a level, though, so I'm ready to hang my head in shame.

Solipsism can't be refuted (of course!) but neither can green cheese gods who are put on the moon by the Great Real God who would fool unbelieving humans. Psychologically speaking (and unfortunately that is about as far as we can go with certain questions) solipsism is not satisfying. At least not for me. Madnak obviously feels otherwise and I appreciate that. In fact, maybe I should try it out for a while and see how it feels. It must be empowering. I feel the same way about "people of faith." If you believe something strongly enough then it's psychologically true.

As a determinist, I know I'm just a puppet. The real question is, who's pulling the strings?

That is only the first sentence of the definition. I think the Wikipedia definition is fine, but the best part of it is this:

"Solipsism is an epistemological or ontological position that knowledge of anything outside the mind is unjustified. The external world and other minds cannot be known and might not exist."

This is critical context given the common perception of solipsism (ie the naive conceptions such as those you linked). Even though it can be simplified into "one's own mind is all that exists," this statement cannot be parsed through a conventional set of assumptions. The best way to express solipsism to someone uninitiated is with that second sentence, and with the following:

Solipsism is the belief that no knowledge other than that of one's own mind can be rationally justified.

This is an important theoretical distinction, but while there are numerous skeptics/weak solipsists, I am not aware of any strong solipsists outside of drug users and psychotics (who are usually only temporarily "strong solipsists," and who usually have no systematic philosophical framework supporting their beliefs).

Not only can OR not refute anything, but OR actually favors solipsism. Solipsism invokes fewer assumptions than views invoking an external reality, but it produces the same results. If you work according to the Razor, then solipsism is your only option.

Kant "joined" rationalism and empiricism by saying "well, we have absolutely no reason to believe in an external world, but because it's necessary to believe in an external world I'm going to do it anyway." He did not actually show that it's necessary to believe in an external world, he just found the conclusions he himself derived to be inconvenient and thus assumed premises that were more appealing to him. This hardly strikes me as rigorous, and I think that is a good summary of my position on Kant: He can be rigorous when he wants to be.

There are numerous problems with this assertion. The first being that empiricism itself suggests solipsism (at least if you accept modern brain science as your model). In fact, empirically speaking, given the basic external world assumptions that we accept, the two hypotheses of "there is an external world that exists in such-and-such a form" and "my brain is sitting in a vat which presents to me the scenario of a world existing in such-and-such a form" are equally supported. There is no logical justification for accepting the former over the latter, and thus a "true" empiricist must always proceed as though he is likely to be a brain in a vat. But that reduces either to absurdity or to solipsism.

The only way to avoid the reduction to solipsism is to assume (with no logical justification) that the brain-in-a-vat scenario is false. Ergo, the belief in an external reality governed by empiricism not only requires the unsupported assumption that external reality exists, but also the unsupported assumption that external reality is as it is observed. I believe that a number of "pile-on" assumptions are also necessitated, but to establish that systematically seems daunting so I'll hold off on it.

No, Kant noted (correctly so) that rationalism lets you prove statements that contradict eachother.

There is no difference in the logic value or truth value of assuming a universe or assuming a mind, both are merely untestable axioms.

Kant made effective critiques of his contemporaries. He did not make effective critiques of rationalism itself (in the general philosophic sense).

Assuming a universe requires assuming a mind. Assuming a mind does not require assuming a universe.