hypnagogue said:
It depends on how one interprets the relevant terms. If objective reality is understood to mean something like "that which exists independently from one's subjective experience" then a solipsist would deny that anything like objective reality exists.
I would even say that it is a necessary requirement to make solipsism coherent as a viewpoint. Rade arrives at a conclusion of logical contradiction of the solipsist viewpoint exactly because of the denial of this denial (hum...). (I have found another example of such a (fallacious) reasoning at the end of this post.)
Of course you get into trouble when a solipsist takes it that objective reality does not exist, but that his body does (which Rade seems to take implicitly part of solipsism, based upon his Webster dictionary definition). Because if the body exists objectively (and corresponds to the perceived image in the subjective experience of its owner), then, because of perceived interactions of the body with other things, you have to postulate also that these other things exist, etc... and you end up postulating the existence of an entire chunk of the universe around you, which is then indeed in contradiction with the original viewpoint of solipsism.
As to what is the standard definition of the concept "solipsism" (which I thought I was adhering to when I used it), maybe Webster is not the greatest place to look up philosophy items.
Have a look here:
http://pespmc1.vub.ac.be/ASC/SOLIPSISM.html
(it is at my home university):
The theory that locates reality entirely in the mind of the beholder. It specifically denies the existence of involuntary experiences with an outside world be it through direct perception of something or through vicarious experiences created in the process of communication. For contrast see epistemology and constructivism in cybernetics.
So there is NO hypothesis of the reality of the BODY of a solipsist.
There is the Wiki entry on it, but I find it less clear on what is exactly assumed:
http://en.wikipedia.org/wiki/Solipsism
In a certain way, the entry on immaterialism
http://en.wikipedia.org/wiki/Immaterialism comes closer ; apart from the fact that several minds can exist in this viewpoint, and there seems to be some collective illusion of an objective reality.
A good read on the subject can also be found here:
http://www.iep.utm.edu/s/solipsis.htm
...except for the strange statement that no great philosopher was a solipsist, followed by the (accurate!) analysis of Decartes' solipsism (which he can only avoid by invoking god). To me, Descartes is the founder of the solipsist idea! As to whether he was a great philosopher...
Also, it seems to me that the "inconsistency proof" of solipsism because of the necessity of public language, in the last section of this link, seems to me to go in exactly the same (misguided IMO) sense as Rade's "proof of inconsistency" by assuming the existence of a body. After all, a single mind could have imagined a "public language" with his illusions of other people, in order for him to formulate, for himself, his ideas about solipsism. The trap of the inconsistency proofs of solipsism seems always to rest on the implicit assumption of of some aspect of objective reality (in this case, the objective existence of "public language", and in Rade's case, the objective existence of a body), hence already including implicitly a contradiction in the assumptions of the "proof", which means it is not difficult to arrive at a contradiction at the end.
For your information, I'm not (necessarily) a solipsist! I only wanted to point out that solipsism seems to be a logical possibility which cannot be falsified, and as such, is a counter argument to all "proof of objective existence" of what so ever without extra assumption. So all acceptance of the objective existence of something must include an assumption which is logically equivalent to assume exactly that objective existence, so it will always have the status of a hypothesis.