Hex, he didn't contradict himself. He simply elaborated on his position (more so than he needed to in order to prove his point, the point was proven with his first and second rebuttals of your claim). You have two jobs at this point in the discussion:

1. Read the first two ******* meditations, it's only about twelve pages so it shouldn't take that long.

2. Prove how you can think without existing. If you can't do this then you must admit defeat.