http://skeptoid.com/episodes/4264
The human brain evolved in such a way as to keep itself alive to the best of its ability. For the past few million years, our ancestors faced a relatively straightforward daily life. Their job was simply to stay alive. Like us, they had different personalities, different aptitudes, different attitudes. This was borne out in many ways, but the classic example that's often used is that something would rustle in the tall grass. Some of our ancestors weren't too concerned, and figured it was merely the wind; but others were more cautious, suspected a panther, and jumped for the nearest tree. Over the eons, and hundreds of thousands of generations, the nonchalant ancestors were wrong (and got eaten) just often enough that eventually, more survivors were those who tended toward caution, and even paranoia. In evolution, it pays to err on the side of caution. The brains most likely to survive were those who saw a panther in every breath of wind, an angry god in every storm cloud, a malevolent purpose in every piece of random noise. We are alive today as a race, in part, because our brains piece random events together into a pattern that adds up to a threat that may or may not be real. As a result, we are afraid of the dark even though there's rarely a monster; thunder frightens us even though lightning is scarcely a credible threat; and we perceive the menace of malevolent conspiracies in the acts of others, despite the individual unlikelihood of any one given example.
Conspiratorial thinking is not a brain malfunction. It's our brain working properly, and doing exactly what it evolved to do.
So then, why aren't we all conspiracy theorists? Why don't we all see conspiracies all day long? It's because we also have an intellect, and enough experience with living in our world that we are usually able to correctly analyze the facts and fit them into the way we have learned things really work. It is, exactly as it sounds, a competition between two forces in our head. One is the native, instinctive impulse to see everything as a threat, and the other is our rational, conscious thought that takes that input and judges it.
To determine when a person is over the line and should be treated, psychiatrists often look closely at the context. Does the conspiratorial belief integrate harmlessly with this person's life, or does it dominate? Has it caused problems: loss of job, loss of spouse, loss of security, or caused sociopathic behavior? These are the types of things that differentiate a belief system from what we call an illness. A person who thinks Barack Obama's birth certificate is fake is not ill, but a person who obsesses over it to the point of driving away their friends and family could well be.
They believe their delusion is real. They will present their evidence to prove it until the cows come home. It's often impossible to get them to consider the possibility that the reality of what they perceive might be due, in any degree, to psychopathology.
World Trade Center 7: The Lies Come Crashing Down
http://skeptoid.com/episodes/4085
No evidence of any explosives were ever found, but the conspiracy theory states that this is because the government took away all the debris before it could be independently tested. Since it's normal for debris to be removed following any such destruction, this particular piece of information is too ambiguous to be given serious weight as proof of a conspiracy.
The claim that fire has never before destroyed a steel-framed building seems to hold up well, as it's hard to find a recent example of it. The reason is that modern building fires are always fought, they have sprinkler systems, and their steel is well insulated. Turn the clock back a few decades to World War II, when there was massive worldwide incendiary bombing of major cities, there were no sprinkler systems, and fire fighters had no hope of responding, there were many hundreds of steel framed buildings that were destroyed by fire. Not by bombs; by fire. The Edo Museum in Tokyo has preserved gnarled masses of giant girders twisted into knots by fire. London's Imperial War Museum has thousands of photographs of the same, and even a large collection of contemporary art depicting warped steel girders. Dresden's City Historical Museum also shows examples of steel girders from buildings that collapsed from fire, during that city's most infamous of all large-scale incendiary attacks. These museum collections all predate any alleged September 11 conspiracy.
There are three videos of the actual collapse that are of decent quality, and all show a collapse that appears reasonably consistent with what most laypeople have seen of controlled demolitions on television. The most obvious difference is that controlled demolitions start with multiple series of minor explosions distributed throughout the building to cut various support structures in a carefully planned sequence, followed a few seconds later by the charges to blow the key structural elements in a sequence designed to initiate the collapse in the desired direction. None of the videos of Building 7's collapse show any minor explosions. They simply show the top of the building begin to gracefully sag, as if it's made of clay, and then the whole thing drops. So while the manner of collapse may look superficially similar to a controlled demolition at first glance, a more careful examination shows critically important (and non-ambiguous) differences.
The neat, tidy arrangement of the debris of Building 7 is another characteristic of controlled demolitions that is claimed by the conspiracy theorists. WTC7.net states that "The pile was almost entirely within the footprint of the former building." In fact, Building 7's debris field was neither tidy nor well-contained within the footprint. The videos of the collapse are all from far away and show only the top portion of the building before it disappears behind the skyline. Lower down, the collapse become much more chaotic. Two nearby buildings were nearly destroyed by it. The Verizon Building suffered $1.4 billion in damage from the collapse of Building 7, but was able to be repaired. Manhattan Community College's Fiterman Hall building, however, was not so lucky, and suffered such major damage that it could not be saved. What remains of it is still being deconstructed piece by piece.
There's really nothing that's either mysterious or unexpected about the manner of Building 7's collapse. It was doomed by the damage, the diesel-fed fires, and the lack of firefighting capability. All the physical evidence, photographic evidence, and testimony of the firefighters is perfectly consistent with the government's official report. The conspiracy theory is supported by no evidence and is inconsistent with all of the events in the 7 hours preceding the collapse. The cause of Building 7's collapse is a question where very little critical analysis needs to be applied by a rational person.