Craig Ferguson says it’s intellect and romance triumphing over brute force and cynicism. Philip Sandifer says it’s alchemy, the secret of which is material social progress. (I may be oversimplifying. You should read his blog.) I suppose I fall somewhere between the two. The thing is, though, that Doctor Who isn’t one show – it’s ten different shows and a movie, not counting Peter Cushing, and what that means for you is affected by how old you were for each Doctor, each massively different TV show with the same name, and where it stood in the culture at the time. Doctor Who is Lenny Henry making Margaret Thatcher jokes in a TARDIS. Doctor Who is Jon Pertwee yelling SPLINK! Doctor Who is any knitted scarf of a certain length or greater. Doctor Who is my nephew mesmerised by an old Peter Davison episode. Doctor Who is the KLF. Doctor Who is holding a sink plunger in one hand and an egg whisk in the other. Doctor Who is so deeply entrenched in the culture that you can’t actually dig it out or say what it is, because Doctor Who is everything.