My good friend Andy Naselli is sitting on the front row watching and live blogging the debate. He asked me if I wanted to ask a question, so I sent this:
If the Son is necessarily the Son and the Father is necessarily not the Son, then the Son is essentially the Son and the Father is essentially not the Son. Thus the Son is essentially different from the Father. Must you not deny homoousion on the basis of your own premises?
This parallels the central argument that Drs. Yandell and McCall were making—and shows its weakness:
If the Son is necessarily subordinate to the Father, then the Son is essentially subordinate to the Father. Thus, the Son is essentially different from the Father, which entails a denial of homoousion.