There is no doubt in the universe that the climax of the 50th anniversary with the multitude of Tardises converging to save Gallifrey from destruction was thrilling. All the Doctors coming together to change history and right a galactic wrong, saving the Time Lords to give them a fighting chance. Resurrecting them all from the dead so they can live on. If the Daleks can do it then by hell, so can the Time Lords. It was the Doctor that killed them all before so it’s only right it is every Doctor that saves them. And given it was the 50th anniversary, it was only right fans got a surprise when the 12th Doctor made a cameo appearance as the 13th Tardis joins its fellows in the fight to save their home planet.
That shot of Peter Capaldi’s eyes made people scream out in excitement BUT logically it couldn’t be possible. When the Time Lord cries out that all 13 of the Doctors are there, I had to stop and think. As we know, the Matt Smith version which is known as the 11th Doctor was in fact the final incarnation. His other two regenerations were used for the War Doctor, his secret life and we will learn that the 10th Doctor’s regeneration counted in The Stolen Earth/Journey’s End as he regenerated into himself. At the time he said that he used enough regeneration energy to heal himself from his wounds at the hands of the Dalek weapon. A Time lord has thirteen bodies, twelve regenerations but in this life cycle, the Doctor had twelve counting the War Doctor. His tenth wore the same body twice.
So how then count the Capaldi incarnation exist? Fact is, he couldn’t. We know that his cameo was a throwout to the fans, an irresistible present from Steven Moffat. As much as it was welcome, it didn’t make sense. The Capaldi Doctor may be known as the 12th Doctor but he is in fact, the first in a brand new life cycle given by the Time Lords at the end of Time of the Doctor. His existence is impossible at this point because 1) he only exists because of Clara’s plea to the Time Lords and 2) in the original time line the 11th Doctor died and was buried at Trenzalore.
So when the 13th Tardis appears in the skies over Gallifrey in the battle with the Daleks, the Matt Smith and David Tennant versions should have had alarm bells ring immediately. They knew there would be no possible way a 13th physical body could exist once Matt Smith’s incarnation died as he did in Trenzalore. The existence of the Capaldi version should actually have created a massive paradox because he couldn’t exist at this point. But as a birthday present I was thrilled. Story logic….well, that’s another story.