Not to beat a dead horse, but here's Noam Chomsky's take on it. I'm not using Chomsky as an authority, but he displays the critical thinking that it takes to be a scholar or a scientist:
Noam Chomsky: 9-11: Institutional Analysis vs. Conspiracy Theory
Submitted by Noam Chomsky on Fri, 2006-10-06 14:09.
Categories: Middle East | United States | US Foreign Policy
The following is an exchange between a ZNet Sustainer and Noam Chomsky, which took place in the Sustainer Web Board where Noam hosts a forum...
ZNet Sustainer: Dear Noam, There is much documentation observed and uncovered by the 911 families themselves suggesting a criminal conspiracy within the Bush Administration to cover-up the 9/11 attacks (see DVD, 9/11: Press for Truth). Additionally, much evidence has been put forward to question the official version of events. This has come in part from Paul Thompson, an activist who has creatively established the 9/11 Timeline, a free 9/11 investigative database for activist researchers, which now, according to The Village Voice’s James Ridgeway, rivals the 9/11 Commission’s report in accuracy and lucidity (see,http://www.villagevoice.com/news/0416,mondo1,52830,6.html, or www.cooperativeresearch.org
Noam Chomsky: Hard for me to respond to the rest of the letter, because I am not persuaded by the assumption that much documentation and other evidence has been uncovered. To determine that, we'd have to investigate the alleged evidence. Take, say, the physical evidence. There are ways to assess that: submit it to specialists -- of whom there are thousands -- who have the requisite background in civil-mechanical engineering, materials science, building construction, etc., for review and analysis; and one cannot gain the required knowledge by surfing the internet. In fact, that's been done, by the professional association of civil engineers. Or, take the course pursued by anyone who thinks they have made a genuine discovery: submit it to a serious journal for peer review and publication. To my knowledge, there isn't a single submission.