Board Thread:Naruto Discussions/@comment-3571355-20150819100444/@comment-24808887-20150822011944

Only logic dictates that he has full power of one eye though. You are using Argumentum ad ignorantiam(it is like say - that ghost exist because no one can prove otherwise), where as right way to use is Occam's razor: Since we don't know if there are quality difference between one eye of Madara's Rinnegan and one eye Sasuke's Rinnegan - simplest answer there are none. And so Tomoed Sasuke's Rinnegan is half of Two Tomoeless Madara's Rinnegans if terms of Rinnegan power(which is again never was specified by Kishi.)