Thaler was trying to argue that the AI itself should hold the copyright for the images it generates.

Was he going that far? As far as I understand it, he was trying to claim that the AI was the author of the work and that he should hold the copyright under the work for hire clauses/being the owner of the AI.

Plaintiff Stephen Thaler owns a computer system he calls the “Creativity Machine,” which he claims generated a piece of visual art of its own accord. He sought to register the work for a copyright, listing the computer system as the author and explaining that the copyright should transfer to him as the owner of the machine.

https://en.wikisource.org/wiki/Thaler_v._Perlmutter,_Memorandum_Opinion_(Dkt._24)