Putting all of this together, it is difficult to figure out what Walton means by God's establishing functions and installing functionaries in a sense that has nothing to do with material origins! Perhaps the most charitable thing to do would be to throw up one's hands and conclude that the book is radically unclear. What could it mean for all the plants already to be growing, providing food for animals, the sun to be shining, etc., but for these entities nonetheless to lack functions prior to a set of specific 24-hour days in a specific week? Throwing up his hands in despair at interpreting Walton is what one scholarly critic, Vern Poythress, essentially does after an exchange with Walton.Like McGrew, it was not clear to me that there is a coherent sense in which things are (or could be) "receiving functions" from God during the (literal) seven days. That is, given that--on Walton's account--the material things (creatures and the like) already seem to be kinds of things prior to the seven day period (and thus have structures, capacities, abilities, etc.), it's not clear what giving functions could amount to during the seven day period. One might hold, sensibly I think, that to be is to be a kind of thing; to be a kind of thing is to have a nature; and to have a nature is to have (a) characteristic function(s).
Walton makes an appearance in the comments section followed by an awkward exchange. (MarcAnthony's over-the-top remark is a good example of what is problematic with open comment boxes). Though I've had a couple run-ins with McGrew, I didn't take her review to be outside the bounds of the ethical norms of book reviewing. I look forward to reading and listening to the other reviews to which she has linked.