Discussions on a ranges of philosophical issues including the nature of truth and reality, personal identity, mind-body theories, epistemology, justification of beliefs, argumentation and logic, philosophy of religion, free will and determinism, etc.
Rev 6:16 and Rev 7:10 seem to offer up that two are present. There are many more verses that just mention one figure and one throne. Not quite sure what the theology is on this. I always figured God would be manifest as the Father and as the Son. Like when Jesus is resurected, he ascends and sits down at the right hand of the Father. I think Judgment and Revelation will look like that.