"Ask yourself if "research" actually means going to websites on the Internet and nothing more."

Quite probably, plus books, and what official records are available. A lot of the official records have been 'lost' or apparently did not exist in the first place - eg information from the flight data recorders, cockpit voice recorders, film from the security cameras at the airports and around the pentagon, the aeroplane black boxes (unprecedented!), various recorded conversations between FAA and the military, forensic evidence from Ground Zero - to name just a few. All lost, unavailable, or not revealed to the public (nor even to most of the 9-11 Commission members).

But in other words, roughly the same 'research' as those who put the other point of view, and the same sort of 'research' that we engaged in when disputing official claims that Saddam had WMD. It is of course not sufficient to apportion blame unequivocally, to draw conclusions according to strict logic, but it is the best we can do, given the limitations that we work under. And, incidentally, it is the best 'you' can do as well: both sides are making judgements only on the basis of probability, building narratives according to the most likely sequence of events.

"Ask yourself if claims made by the 9/11 "truth" movement constitute evidence or are just claims and assertions. And for what purpose."

1. I would ask you exactly the same questions for the story you have built up: on what evidence is the claim made that everyone in the administration acted in good faith, and that 'al-qaeda' was wholly responsible for what happened? You too apportion blame, and need to back that up with evidence.

2. The 'claims' made by the 9/11 truth movement are, most convincingly, precisely claims about evidence not having been taken into account by the 9/11 Commission, or about conflicting pieces of evidence within the Commission's report, or about 'evidence' being altered at different stages of the investigation. What is particularly troubling about the 'official story' is that it does not incorporate all of this into a coherent narrative - it simply omits it (even, sometimes, having heard and taken note of it).

3. "For what purpose" Well... you will laugh - but how about for the sake of truth – and maybe even justice!? It is hardly a good career move to doubt the 9-11 'official story', so we can rule out that as a motive; it is hardly something which gains one respect among peers / colleagues, and it is hardly as if those who have bothered to look into the story carefully have nothing better to do (I think?). They may be wrong, stupid, irrational for doing so ... but I can see no other 'purpose' than that there is a sense that something has been left out, unaccounted for, and justice has not been seen to be done satisfactorily. It is, after all, far easier, less troubling, smoother to believe this was an outside job: a great deal needs to be explained (I agree) if it was not. For me, however, that is one reason to look deeper into people's motives for doubting what seems, at first glance, to be so obvious, so easy to accept. Your explanation for their doubts is (?) that they want to believe in something more exciting – and that may indeed be true of some (or even many). I don't believe it's true of all (or even most) – partly because the alternative version is neither exciting, nor comforting, and partly because of the social 'costs' of being seen to be a 'truther' are fairly high. It is definitely not something that one wants to publicise about oneself!

"Ask yourself if it is legitimate to buy into 9/11 conspiracy claims that there is in fact any "official story". What is this so-called "official story"? Why is that term used? Is it propaganda in the true sense of the term?"

OK - I use 'official story' as a shorthand, to indicate, roughly, that the findings of the 9-11 Commission were on the right track, that there was no inside knowledge / culpability, that this was an outside job which came as a complete surprise to anyone who could have had a role in mitigating the effects. Some of the 'conspiracists' refer to the 'official story' as a conspiracy theory - do you prefer that? What term would be neutral? (and are you sure that you deserve neutrality!?)

"I'll suggest to you that "official story" is a termed used to deliberately obfuscate the reality of what the evidence actually is and where it comes from. Does the actual evidence originate with and all come from the government? If so, how?"

By no means exclusively, but to some extent, yes. A lot of the evidence (tapes, film, forensic) has been 'controlled' to a surprising degree by people in or close to the administration. For one thing, only part of it has been made available to the Commission. For another, conflicting evidence - such as reports of eye witnesses, including firefighters, has simply been left out of the final discussion. To give 2 small examples: the testimony of Norman Mineta, which gave information about the time Dick Cheney learnt about the attacks and what he said was not included in the final report, and nor was a memo by Laura Brown which contradicted the military's amended timeline - and there are very many other examples. Information was simply left out of the 9-11 Commission's discussion where it conflicted with the 'official line', and that included some of the initial evidence given by the military, FAA etc which was inconsistent with their own later version of events. Then again, some of the evidence could only be seen by a selected number of the commissioners (let alone the public!) – and this was largely decided by the executive director of the Commission, Philip Zelikow, who is a Bush appointee, close associate of Condaleeza Rice etc.

"Or does the evidence come from thousands of independent, disparate, and unconnected sources, never controlled by or exclusively in the possession of the government?"

Some of it does, and I would say that is how we are able to build up alternative versions. Of course all of the evidence cannot be controlled in a country such as the US. But some can, and they can 'control' aspects of the investigation such as which questions are raised, how they are discussed, who sees the available evidence, and what goes into the final report.

"Are the investigations by NIST and ASCE secret, thoroughly controlled and investigated by the government exclusively, it's evidence, procedures, and methodology hidden form analysis and criticism by anyone?"

No – but you know as well as I that 'control' works much more subtly than that in today's 'democracies'.

"Or were they made up of a majority of non-government, independent scientists, their evidence, methodology, and conclusions fully transparent and open to the world's structural engineers, physicists, chemists, architects, and forensic scientists for criticism, debunking, or affirmation?"

I sense that you are again stuck on the science, as if this was the only aspect that the 'conspiracists' dispute, and as if this was the only conflicting source of evidence. I don't feel ready yet – and may never be, given my limited scientific understanding – to form a conclusive judgement on the alternative scientific accounts. But I regard that as a secondary issue, at least for the moment. The evidence which is most troubling to the official view is in my view - and as a layperson - not connected with the science, so much as with the enormous number of coincidences, anomalies, inconsistencies, deliberate concealments and outstanding failures of a highly secure and normally functioning system. It is that abnormally high number of anomalies which I think should make anyone want to look for interpretations which explain them - even if they do not in the end endorse any one of them.