Re: Could the Doctor be a horse?
I was reading The Eternal Tide (no spoilers in this thread) and at one point the Doctor and some dude have a 2 hour walk ahead of them through a desert. The Doctor is saying they might not make it in time because HE can keep up a pace and not tire but the dude according to the Doctor's scans is not at peak physical shape and will be slowing them down before they are halfway there.
Why couldn't the Doctor just program his photons into a horse.. or a dune buggy and take the frail human for a very fast ride to their destination?
Perfectly reasonable question, or just carry him as is. I'd guess that carrying the guy would use up power faster than would allow them to make the journey. But there really should be no problem with changing shape, number of arms or what have you. The limit is the desire of the plot. All those times on Voyager complaining of needing help, there's no reason the holocomputer system (which really is the doctor) couldn't project another hologram.
We are quicksilver, a fleeting shadow, a distant sound... our home has no boundaries beyond which we cannot pass. We live in music, in a flash of color... we live on the wind and in the sparkle of a star!' Endora on witches in Bewitched