He hunts around for justification, doesn't find anything satisfactory, or even paint a clear picture of what "satisfactory" would look like, and ends up conveying mostly mysteriousness to the audience.

A.) It's not a journal article. B.) He "conveys mostly mysteriousness to his audience" only if what you mean by that is that he explains and explores a problem while admitting he does not have a complete answer yet...

Great. And not problem, just a miscommunication then.

"Possible worlds" doesn't mean spawning any physical universes - it's a convenient shorthand for imagined possible worlds, which we (in our capacity as intelligent apes) compare against each other, usually as part of a consequentialist decision process.

Whether or not possible worlds are 'as real' as the actual world is a different question from whether or not "possible worlds" equal "imagined possible worlds. The answer to the second question is almost certainly "no". For a world to be possible it is not necessary that someone imagine it.

The basic idea is that death being bad is, at its root, a function of the decision-making bits of our brains. This can be seen not just from a priori claims about "low utility = bad," but from the structure of what Shelly Kagan hunts around for, which mainly involves choices between possible worlds.

The causal history/ cognitive explanation of the idea of death being bad is not the same as a justification for it. It of course makes sense that humans would have evolved to worry more about not dying than about not having begun living earlier. But the normative question is about what we should value and why. I tend toward the non-realist camp myself so I'm tempted to answer "there isn't and can't be an answer to the normative question". But if you're worried about the behavior of very powerful agents trying to extrapolate human values the question of whether or not "death is bad" is inconsistent with our other values and beliefs is important. I thought the article was a rather good survey of the major arguments regarding this particular value question, though, if it hasn't had it already, the subject would benefit from a cognitive science based approach.

Kagan does feel that death is "bad", but he only throws this in at the very end after spending the entirety of the article arguing the opposite.

He's not, not arguing the opposite. He's doing philosophy by Socratic method. I really hope this wasn't a common misinterpretation here.

How is it worse for you directly?

What accusation? I'm just describing your post and asking questions about it.

Edit: I mean, obviously I have a point of view. But it's not like it was much of a stretch to say what I did. I just paraphrased. How is my characterization of your post flawed?

I'm pretty sad a post that consists entirely of tribal signaling has been voted up like this. This post is literally asking people to publicly endorse the Sequences because they're somehow under-attack (by whom?!) and no one agrees with them any more. Because some of us think having more smart people who disagree with us would improve Less Wrong? I find glib notions of a "singularity religion" obnoxious but what exactly is the point of asking people here to announce their allegiance to the site founder's collection of blog posts?

I can't understand this. How could the sequences not be relevant? Half of them were created when Eliezer was thinking about AI problems.

That doesn't mean anything said in them is responsive to Holden's arguments.

Obesity is not a boon to IQ.

Such a scan isn't possible with present technology. What is possible are scans and other methods of recording information that could conceivably be relevant to an attempt to reconstruct your mind at a future time. If the argument is simply that brain scans "couldn't hurt"... well, 'duh'. But making a diary of your frequent thoughts or videotaping yourself as you go about your day couldn't hurt either. Knowing the regional blood-flow patterns in your brain in response to narrow and limited stimuli is not in a significantly different category.

The question is whether the cost and time involved in these endeavors is is better than plausible counter-factual spending. My point isn't just that SI shouldn't purchase a machine; it's that giving to existential risk research, or ensuring the financial stability of your cryonics organization probably has a better return for your own long-term survival than getting frequent fMRI scans does. The point that spending money on brain scans has a better return than an expenditure that probably lowers your long-term survival rate (due to car accidents) is not a strong argument.