Yes, it does attempt to give one-- but I didn't find it particularly satisfying. But some of the replies in this HN thread have been better in that respect, for

Yes, it does attempt to give one-- but I didn't find it particularly satisfying. But some of the replies in this HN thread have been better in that respect, for me at least. The idea that it's just an extension of why the area of a triangle is 1/2 the enclosing rectangle to 3 dimensions to me is the "oh, that's why" framing for what otherwise seemed sort of magical to me.