Submitted by a contributor:
In the Duffy-Slick debate, near minute 55, the where God said he could do something which he did not do, Slick talks about “shades of meaning” for the word “ability” and “possibility”.
“Could God have done it?” may have been the better phrasing of the question to avoid Slick’s maneuvering and focus on the question. The real question is whether God lied.
If Slick asked, “what ‘could’ means”, the proper answer is “just what it means in that scripture that said that God could do it.” If Slick answered yes, he contradicts the Calvinist position that all decreed events cannot be changed. If Slick says no, he contradicts the Bible.