Board Thread:Theories and Speculation/@comment-31660872-20170403131802/@comment-734582-20170408080736

Starscream1998 wrote: Nope, if anything it's the other way around; Obito had doubts about the path Madara set him on and ultimately couldn't follow through with it as he was shown having major regrets in his battle with Naruto and Sasuke. Madara 100% believed in the Infinite Tsukiyomi and never realised how wrong he was about it until it was too late to do anything. I think Obito realized that he couldn't really not complete the plan. He was aware of the Curse Mark and with Black Zetsu around, he would never really get a chance to fully stop the plan. He was also depressed and disillusioned with the world, so it wasn't like he cared deeply.

I think during the fight with Naruto he realized that he may have given up too easily about the world, and that maybe there was something worth fighting for. He definitely wanted Naruto to crack, to come to the same conclusions as him and basically see a justification for the end of the world, but it never came and so Obito's doubts only grew.

Madara on the other hand, had achieved the Sage's power and so unlike anyone else, he didn't just believe in the plan but knew it was possible and in fact effective. Madara saw not just an ideological solution (like Nagato) but also a practical solution that according to all his power and knowledge, should work.

He had no reason to doubt his plan. Everything he could do, all the power he had and all his knowledge told him that it was a solution that would actually work.