Can you teach yourself?

[drfuzzy]

Well, provided your reading and cognitive skills are good, and this is something that can be learned by text - history, math, most science, philosophy, etc. - sure. If there is something you need to have demonstrated, (such as a simple home repair, fixing a cellphone screen, etc.) and you have access to a good video - sure, although it could be argued that whoever created the video was your teacher.  You can even learn to speak a language now with the help of various software applications - as long as you choose one that gives great examples, can listen to your input, and give you good feedback.  Again, it could be argued that the software served as an instructor. 
   However, if it is a physical skill that requires flawless technique, no.  You can teach yourself to play guitar chords, but you cannot teach yourself to play advanced classical works, because a flawless economy of movement is required to be able to play the right notes at the right time, with the right balance of tone, song-like phrasing, and dynamic expression.  Anybody can strap on ice skates and learn to stay upright while moving forward, but just try to learn how to do a triple lutz without a good coach.
  So, the short answer I would give to the "can I teach myself?" question is: it depends upon what you are trying to learn, and what level of skill you want to attain.