SilasBarta comments on Metaphilosophical Mysteries - Less Wrong

35 Post author: Wei_Dai 27 July 2010 12:55AM

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Comment author: SilasBarta 27 July 2010 08:39:52PM 0 points [-]

A universal prior must enumerate all the ways a universe could possibly be. If your prior is based on Turing machines that compute universes, but our actual universe is uncomputable, you're screwed forever no matter what data comes in.

Being forced to use the nearest computable approximation to an uncomputable function does not make you screwed forever.

Comment author: cousin_it 27 July 2010 08:42:01PM *  1 point [-]

That depends on the uncomputable function. Some can make you very well screwed indeed. It's all there in Wei Dai's examples on everything-list and one-logic, I really wish people would read them, maybe we'd have an actual discussion then. Sorry for sounding harsh.

Comment author: SilasBarta 27 July 2010 08:49:08PM *  1 point [-]

That depends on the uncomputable function. Some can make you very well screwed indeed.

Right, but it's not necessarily true, or even likely, hence my point.

It's all there in Wei Dai's examples on everything-list and one-logic, I really wish people would read them, maybe we'd have an actual discussion then.

I did read the links, (including the link to the empty stub article!), and the google group discussions all seemed to end, from my brief perusing of them, with them coming to the consensus that Wei Dai hadn't established his provacative, counterintuitive point. (And some of the exchanges here show the same.)

At the very least, he should summarize the reasoning or examples, as per standard practice, so we know there's something to be gained from going to the links. This is especially true given that most readers had assumed that the opposite of Wei Dai's premises are true and uncontroversial.