It's perhaps splitting hairs, but...
Scope creep...
Connection to and
caused are not the same thing.
Agreed, though there is what I would term *diagonal slice* post initiation...
http://www.youtube.com/watch?v=gkS58AwDX0E
http://www.youtube.com/watch?v=Tr5GJwfLCl4
...which does appear to traverse bottom-up.
Not agreed.
I'm quibbling use of the word *can't*. IF an explosion low down severed some of the inner core columns, leaving the outer columns intact, then all manner of load redistribution would ensure. It would not affect the visible core remnants as, for WTC2 the core remnant is only glimpsed through dense dust making stating inner core columns were present speculation, and for WTC 1 the core remnant that was visible did not include inner core columns.
I'm not saying *there was an explosion and it took out the inner core low down*. I'm saying that use of the word *can't* is not appropriate. It's *possible*. Probable or plausible are different words.