Lewis would likely have regarded himself as committed to accepting every moral claim he thinks was made by God. He might not believe that the Church of England is perfect at figuring this out, but whatever source of God-claims he uses instead of the Church would produce results as arbitrary as using the Church. (Except to the extent that he uses motivated reasoning to decide what God is claiming.)
It is not “motivated reasoning” to argue that God doesn’t claim a thing, if you have reasons for believing both that the thing is false, and that whatever God says is true.
Lewis would likely have regarded himself as committed to accepting every moral claim he thinks was made by God. He might not believe that the Church of England is perfect at figuring this out, but whatever source of God-claims he uses instead of the Church would produce results as arbitrary as using the Church. (Except to the extent that he uses motivated reasoning to decide what God is claiming.)
It is not “motivated reasoning” to argue that God doesn’t claim a thing, if you have reasons for believing both that the thing is false, and that whatever God says is true.
Lewis, however, does believe that God makes moral claims and that he (Lewis) can know what at least some of them are.