Hey, OP, try this "hybrid" theory on for size!

1. Terrorist chatter was up all through early 2001 and only increased in August right before the event. A LOT of people knew something was up.

For evidence (since you are probably a scientific type) go to

www.historycommons.com

then go to their 9/11 Complete timeline, and look under precursor events or warnings (some title like that). You'll see that the U.S. security was on high alert. There were even specific warnings about planes being used (don't believe Bush & Rice when they claim "no credible signal").

2. The WTC was obviously a high value target and people in the know would have been worried about it coming down.

3. What's worse than two giant towers falling into their own footprints and killing 3000 people? Two giant towers TOPPLING over onto other buildings and killing 10s of thousands.

4. Answer: Prepare the buildings for a controlled demolition should the unthinkable happen. It did, and the plan worked.

5. Why lie about it: How can you explain to the families of the 3000 that their loved ones died to protect the 10s of thousands? You can't. It's a horrible decision that no one wants to make but in fact it gets made in warfare all the time.

QED