It's been almost 13 years and the nonsense shows no sign of stopping. It is still amazing to me – thousands of direct eyewitnesses saw two passenger jets plow into each of the twin towers. Further, there are countless videos from multiple vantage points clearly showing these events.

Also keep in mind that after the first jet hit the North Tower, media attention descended onto the towers. The media was in full force when the second jet hit the South Tower. In addition, many personal video cameras were up and running. It is therefore an extensively documented event.

In the face of this overwhelming direct eyewitness and corroborating video evidence, who could deny the basic fact that two jets struck those two towers that morning?

Well, this guy, for one. I know this is beating a dead horse, but I think it is useful to have occasional reminders of the extent to which people can deceive themselves into absurd conclusions. It should also be noted that, while apparently declining in more recent polls, belief in a 9-11 conspiracy remains high. Averaging all surveys, less than half of those asked accept the standard explanation that 9-11 was an Al Qaeda plot.

One of the ways in which people arrive at and then reinforce conclusions that are demonstrably absurd is anomaly hunting. This is a common part of the conspiracy theory process – look at any complex event and hunt for any apparent anomaly. Does anything not make immediate sense or stick out as unusual.

This is a form of data-mining – looking at a very large set of data and hunting for patterns or statistical quirks. Any large set of data will contain these things by chance alone. All the details that make up a complex event represent a large data set, and so apparent anomalies and unusual coincidences should be common.

This mental error is then combined with the false conclusion that because there are apparent anomalies, something must be wrong with the superficial or official story. Conspiracy theorists are very impressed when they find anomalies, because they work from the false premise that if there weren't a cover-up, then no such anomalies should be apparent.

Apparent anomalies, however, are everywhere. If you look you will find them.

This latest YouTube video is a perfect example of anomaly hunting. The author, pouring over videos of jets crashing into towers, thinks he has found evidence that the video was faked. He points to the appearance that the wing of the plane seems to pass behind a building in the background. He concludes this is a "layering error" and is therefore evidence the entire video is faked.

There is a far simpler explanation, however. This is simply an optical illusion and an artifact of the video. The shade of the wing is very similar to that of the building in the background, so when the two are overlayed the video camera cannot separate the two. The wing therefore disappears into the building, which our brains then interpret as it being behind the building.

You can see that this is true because on the nearer side of the building, which is more lit by sunlight, the wing is much darker and we can see it pass in front of this side of the building.

The video, therefore, is not evidence of CG. This is just what happens when you zoom in on such video – artifacts appear and can sometimes produce optical illusions.

This, of course, is a much simpler explanation than the claim that thousands of eyewitnesses were somehow deceived, that hundreds of videos were all faked, that the passengers on those jets were made to disappear, the buildings were demolished, and all the other elements of that day were faked without leaving any hard evidence behind. The more you think about the implications of a conspiracy, the more absurd it becomes.

The new video also claims that the jet would not have penetrated the building as it did. This is just naive, and a bit arrogant. Why would anyone presume to know intuitively what should happen when a passenger jet loaded with fuel flies into a building at 466 mph. The kinetics of such an event are totally outside our everyday experience.

The momentum of that jet had to go somewhere, and the exploding fuel would have provided even more energy. Further, the towers were constructed with their supports on the inside, and so the outer shell was more fragile than for most other similar buildings.

This point is not even an anomaly.

The true lesson here is to never underestimate the extent to which people can convince themselves that the absurd is true.