10 Reasons Why The New Doctor May Actually Be River Song

10. The Chameleon Circuit

We witness as Whittaker's Doctor realises why her sonic screwdriver could not uncover Ruth Clayton's identity - it was the Chameleon Circuit. The TARDIS's protocol of disguise had serves Martin as a form of camouflage. However, it might go further than just one disguise.

Just as Ruth Clayton is a disguise for this new Doctor, this new Doctor is a disguise for River Song. As seen within David Tenant's episode 'The Family of Blood', we see the Doctor hiding his identity in the form of a human. The changes to both his genetic signature and his personality are apparent. While the Tenth Doctor becomes a teacher of his time, River Song becomes the Doctor.

She adopts his mannerisms such as not answering questions and fast-paced thinking. There is nothing to say that the Chameleon Circuit cannot be used to disguise itself on multiple levels, and with the complexity of Doctor Who, we wouldn't put it past them to write it - crazier things have happened!