Board Thread:Theories and Speculation/@comment-27924662-20160817160245/@comment-25122992-20160822181941

I believe that in any case Rinnegan =/= SPC, because according this equation, Naruto must've got Rinnegan as well after receiving Hagoromo's SPC. At least, the SPC helps to awaken the Rinnegan only when it infuences the eye nerve directly, the same way when Uchiha's special chakra from the brain affects it and awakens the Sharingan > MS. But it doesn't happen for every person who got SPC. More specifically, it happened with people prone to the visual prowess (the Uchiha, i.e. Madara and Sasuke), which is explained either by their eyes having a special type of chakra which produces a special type of doujutsu (the Rinnegan) when combined with SPC, or by their bodies having an "affinity" for ocular power and thus advancing it with the SPC in the first place.

Besides, UltimaDude, as I see, you admitted that SPS and the Rinnegan aren't the same power yourself, which means that for both of them, some component aside from SPC is necessary.