notsonewuser comments on Where Recursive Justification Hits Bottom - Less Wrong
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When philosopher Susan Haack wrote "Evidence and Inquiry" back in 1995, she really hit the nail on the head on this one. I'll share an extensive quotation from her, and then I'll make a couple remarks:
My main remark is that Eliezer doesn't need to rely on induction to justify induction. The mere assumption that the universe has natural laws is enough. Given that, one can look at the universe timelessly, and say, "I see evidence of this natural law, and, given that the universe has such a natural law, this will happen tomorrow." Then we aren't predicting the future based on the past; we're predicting the future based on our conception of the natural laws of the universe, which just happens to arise from observations we've made in the past. This removes circularity, but requires an additional assumption (which, if false, implies skepticism, as far as I can see).
Of course, standards of evidence do need to be evaluated circularly, but as both Eliezer and Haack noted, the circularity is not vicious.
As for Occam's Razor, Haack doesn't mention it much, and I'm still working out my own thoughts on the problem. I think Kevin Kelly's work is promising, in spite of the fact that he rejects Bayesianism (and consequently, his approval on Less Wrong was mixed when he was previously mentioned). Of course, the proofs of the optimality of Solomonoff induction are probably really, really important here, too. I need to study this more; I'll post another comment (probably not for at least 6 months) giving my position after I've actually done enough research to be confident in a position.
Edit (over a year later): I no longer have plans to do further research on Occam's Razor. I will add that, though I find Kelly's work interesting, I don't think it is a panacea answering once-and-for-all why Occam's Razor works, or is justifiable.
Well, if his evidence for the existence of natural laws is not itself based on induction, he escapes circularity
No one knows what a natural law is, and no one has detected one by direct inspection. The popular answer, that they are "just descriptions" fails particularly badly if one is trying to demonstrate how one has avoided circularity.
PS thanks for the Kelley link.