Quote Originally Posted by XanBcoo
Yes, but he's not deducing the effect of Mangekyou based on his experiences with his own Sharingan. He figured them out for the reasons he stated in the episode. He could have been dead wrong, but Itachi's reaction clarified this reasoning.
Yep I agree completely. I was just arguing against what some people said about how Kakashi must have deduced MS's effects on the eyes based on his experience with S. Therefore, he must have researched or had first-hand experience with MS and its effects on the eyes. After he got owned by Itachi in their last encounter, I would expect that he researched everything known about MS, and that's how he knows more about it, without actually knowing how to do the technique.