Friday, November 04, 2011

Curry on fuzzy logic

Before I get on to the meat of some more new papers...

I noticed not so long ago Curry and Webster flying a kite about fuzzy logic being a better alternative to Bayesian probability, in the context of D&A:

The logic of the IPCC AR4 attribution statement is discussed by Curry (2011b). Curry argues that the attribution argument cannot be well formulated in the context of Boolean logic or Bayesian probability. Attribution (natural versus anthropogenic) is a shades-of-gray issue and not a black or white, 0 or 1 issue, or even an issue of probability. Towards taming the attribution uncertainty monster, Curry argues that fuzzy logic provides a better framework for considering attribution, whereby the relative degrees of truth for each attribution mechanism can range in degree between 0 and 1, thereby bypassing the problem of the excluded middle.


As you will recall, I've been waiting for a year now for Curry to explain her muddled and confused approach to probability, in particular her nonsensical "Italian Flag" analysis which she seems to be recasting as "fuzzy logic" (as an aside, I do agree that her logic is fuzzy, but perhaps not in the way she intended).

So I was eagerly awaiting "Curry (2011b)", which has just appeared. And what does it say about fuzzy logic?

[fx: tumbleweed]

Not one single mention, that's what. No mention of Bayesian probability, either. Or Boolean logic. These terms are completely absent from the paper, so this whole line of specious assertions has simply been abandoned without any support whatsoever.

12 comments:

Belette said...

Isn't ref'ing unpublished papers somewhat uncommon? I forget. I thought some journals don't even let you do it, perhaps for this very reason.

James Annan said...

Not generally forbidden IME, but it's obviously a bit of a risk if the other paper is still to go through review. Of course, Curry may not care, she can now cite the BAMS article and trust that no-one will check up on the paper trail...

Paul said...

She said "fuzziness". Heh...heh

Dikran Marsupial said...

The use of the f-word is inexcusable in a scientific paper! ;o)

Anna Haynes said...

There's reportedly a reply to this post somewhere in Curry's "null hypothesis" thread. If anyone finds it (I'm busy elsewhere right now) please report back.

Anna Haynes said...

(I did a quick search & wasn't able to find it; on the other hand, I wouldn't be surprised if it's under my nose)

James Annan said...

No, the NH thread was where I pointed out that she was misrepresenting the IAC report.

David B. Benson said...

It is essential to realize that fuzzy logic uses truth degrees as a mathematical model of the vagueness phenomenon while probability is a mathematical model of ignorance. from
http://en.wikipedia.org/wiki/Fuzzy_logic
and the short paragraph on a comparison to probability is too lengthy to copy here.

While obviously not as well developed as probability theory, there are applications. I fail to see how a replacement by fuzzy logic would enhance attribution studies. Nonetheless possibly such an attempt would led to a better understanding of attribution?

James Annan said...

It's possible that it could be developed into an interesting approach. It seems unlikely that Curry has anything substantive to back up her claims, though.

Steve Bloom said...

In any case her goal would seem to be unenhancing them. I suppose we can thank the cosmos that neither she nor Peter (to the extent he's providing more than the minimum support required by spousal loyalty) have the chops to do so to any meaningful degree, although a quick glance at M.A.'s article in the same issue plus his history on other issues makes me think the job is already being done. Fortunately he doesn't seem to carry enough weight to do lasting damage.

James Annan said...

If my spouse showed any signs of going off the deep end to the extent JC has, I'd consider it my duty to straighten her out pdq!

Anna Haynes said...

re Annan's "No, the NH thread [where jc responded to ja] was where I pointed out that she was misrepresenting the IAC report." [& not pointing out the discrepancy between characterization of WIRES article & actual article] -

Likely this is my bad - looking at my email to JC, I likely wasn't clear enough (I'd provided a link to this post, but didn't say what was on it) - so I've sent a followup email asking again but more clearly.
(not the most important thing in the world, but it'd be nice to have it cleared up)