>However, the dark side of the moon still exerts a gravitational force on me. The mass of all the moon is present in my observations (though ridiculously small and subtle, it is still present), even the parts that aren't observed visually must still be real in that respect.

Substitute "black hole" instead of "dark side of the moon". Or your favorite celestial body which can be observed only in infrared or x-ray parts of the sprctrum. Continue in that direction... at what point does it stop being real?

>>How real is mathematics? It could be construed as our collective imaginative work, that we for some reason treat as proof, but is it real? Could be the real mathematics (or physics, for that matter) of the current universe is something completely different from our toy.
>
>Mathematics is a human language like English or dBase. In that respsect it is very real.

You know that for me even deities are real in that same respect - as human ideas. But does this human language of mathematics reflect reality (at least when applied as a tool of physics), the one reality that supposedly exists independently from human perception?

I don't have an answer to this. I'd be lecturing somewhere if I did :).

>There is no logical flaw is solipsism. But my critique of objectivism has not much to do with logical flaws as practicality. Can it be used to solve problems? If no, then it isn't much use as a philosophy.

Ah, the utilitarian principle. As comrade Deng would say, "it doesn't matter what color the cat is".

Well, from what I've read in this thread, Rand's objectivism does its homework - it gives the lassez faire capitalism a brownie point and a feeling that they are justified in whatever they are doing, since even science proves they're doing the natural and desirable thing. Each political power had such a theory to back up its will for power. So it does solve their problem; they couldn't just revamp any old theory which praised lassez faire, 'cause those were ground finely long ago. They probably needed a new one, and they got it, problem solved.

>Another important question is are there other philosophies that are better at solving problems? If yes, then there is something more useful as a philosophy.

The more important question is "whose problems". Yours, mine, big money's, economy's, world population's, humankind's; in the short run, in the long run...?

>What then is a "fact"?
>
>I've been assuming it is a statement in language. If it is something other than a statement of language then you may be right. But then what is fact?

A statement in whose language? If there's a reality independent from human observation, then there'd be two sorts of facts - the statements in some reality-per-se-language, which stand independently from our knowing, and the statements in human language(s). The two may or may not coincide. But then, in such a dual system, as soon as you start self-referencing (qv in GEB book, of course), we've sped up the enumerable path towards infinity of levels of self-referencing. IOW, such languages would have a problem talking about themselves, which then creates a problem when discussing them, as we're using one of such human languages right now, and can't even decide the existence of a hypothetical reality-per-se-language.

>There is one more premise that Rand assumes and it is that man shall not be sacraficed for another man. Lazze fair capitalism is best political-economic match for the premises.

Are you sure she didn't mix up her cups around page 200? Lassez faire leads to a free-for-all grab of resources, competition until extermination until monopoly, exploitation unbounded and the human victims along the way don't count as sacrifices, because there's nothing sacred. Now if you start talking of morality, laws etc - that's not lassez faire anymore, that's regulation.

Too bad I couldn't get to any conference this year. We could have discussed this over another couple of Jägermeisters :)