Why is Carson saying this? Is there possible truth behind it or is he just looking for attention?

Edit: I just couldn't wrap my head around why a candidate would be talking about Egyptian pyramids and alternate theories. Apparently it's a little more complicated. He mentioned his own "personal theory" about pyramids during a speech 10 years ago[0], it got brought up recently by the 24h news cycle and now he's defending his theory.

[0] http://www.theguardian.com/us-news/2015/nov/05/fact-check-be...