Synaesthesia

Clutch,
I find the fallacies of academics interesting precisely because they tend to go wrong in interesting ways.

Putting evoltionary theory and atheism into my statement would make it wrong. So what? Putting intelligent design and fine tuning would keep it's truth value constant.

Unsupported swipe? Well if you equate the doomsday argument to the theory of evolution it's unsupported. Otherwise you could simply read the rest of my post.

Clutch

Syn, I must not have made my point very clearly. My apologies; I'll try again.

If by "taking the DDA seriously" you mean "believing the DDA is sound and straightforward", then you're not describing most of the academic treatments of it.

If by "taking the DDA seriously" you mean "finding the argument (i) sufficiently interesting, however wrong and/or (ii) sufficiently influential in public or quasi-academic discourse to be worth refuting", then you are not accusing academics of having any view that you do not share, since you have devoted non-trivial efforts to discussing it on this very thread.

Neither case supports your shot about the delusions of academics, which, your personal views about evolution, atheism and the DDA aside, call to mind the anti-intellectualism of creationists: "Those academics hold views different from mine, and spend time on things that bore me -- aren't they full of delusions!"

Synaesthesia

Clutch
Well there you go, you’ve found reason to assume that’s not what I meant. It is customary to attempt to make sense of what someone says BEFORE you attack them for being nonsensical.

Anti-intellectualism? Well I don’t know how you read THAT into my post. Perhaps a wee bit cynical about human nature, but hardly anti-intellectual.

beausoleil

Sorry, this must have seemed bizarre. I was thinking about it but never got round to posting it (unless I'm now missing it) - too much British beef, obviously.

beausoleil

Here are a few thoughts, just to stir the pot. Mostly prompted by the book review cited above.

<a href="http://www.lrb.co.uk/v21/n13/gree2113.htm" target="_blank">http://www.lrb.co.uk/v21/n13/gree2113.htm</a>

Is it agreed that the urn argument in itself is correct? I bring along an urn and start pulling names out at random until I get to yours at number 'n'. I then ask you to guess how many names were in the urn when I started. Your best guess is 'n'. More easily conceived, perhaps, if n=20 the chances of their being fewer than 40 are higher than of their being more than a million.

Greenberg's 'in the pool' argument seemed to work just as well against this, however, as against the Doomsday argument. This suggested to me it is incorrect. but see below

Equally, this argument - "That the person selected is alive at the starting point is an inevitable artefact of the procedure, and thus cannot affect the probabilities of the hypotheses." also seemed to be analogous, and thus incorrect. Clearly the person's name that has just been pulled from the urn is an artefact of the procedure also. But see below

Is this urn argument still true even if I am pulling the names out according to some pattern you are unaware of? Alphabetically by Great Grandmother's maiden name, for instance. I suggest it is - that you would be justified in making the deduction since, in the absence of knowledge about the pattern, you have to consider all conceivable patterns, which covers the same space of name sequences as all possible random patterns.

But this latter seems to me to be the same situation as described by Greenberg here-

"But if the first 100 billion humans would be the same regardless of whether Doom Soon or Doom Delayed is true, it is false that your living now would be more likely on Doom Soon than on Doom Delayed, and the probabilities of the two hypotheses are unaffected."

So I think this criticism is incorrect.

I think the flaw in the doomsday argument is that the urn argument as stated is a poor analogy. Consider this situation:

I come across an urn with a button that dispenses names one at a time. I push the button a few times, until I have twenty names. I look at the 20th name, then go and inform him that he was 20th out. Is he then justified in making deductions about the number of names in the urn based on his position at number 20? Clearly not, even though his appearance at number 20 from the urn was completely random.

Having got this far, I now think this is in part what Greenberg is getting at. But I don't think he made his point very clear. Note that the history of names 1-19 from the urn is completely irrelevant, for instance. The problem is that the method of selecting a random person is the same as the process the random person is supposed to sample.

That's how I've come to understand it, anyway.

beausoleil

But the problem is that it isn't an applicable argunment. The person with the urn goes to everybody as their name comes out, he doesn't single out the 20th person. Ultimately, I think the doomsday argument is correct - in a population that grows exponentially and then dies out suddenly,if everybody believes the end will come in the near future, they will more often be right than wrong.