Do we have any evidence that this is transfiguration, rather than a charm or some other spell?

 

No, but it makes a physical change, so the assumption should be that it's transfiguration. The burden of proof is on someone to show that it isn't. On the face of it, it seems to clearly be human transfiguration, very similar to what was being done in sixth year transfiguration class, in which Ron transfigured himself a moustache and Harry changed the colour of his eyebrow hair.

Ah, but this is the point -- in the case of things like chess pieces and the Sorting Hat, it isn't temporary. It's a much more fundamental change that allows the object to think for itself and behave as if it were alive. It's essentially turning the object into a living creature, albeit one that happens to be made of non-organic material.

That seems fundamentally different to using magic to actively control the position of an object. (On balance, Dumbledore's animation in OotP appears to be charmswork though, as the statutes show no sign of reluctance to jump in front of curses, unlike living creatures, which try to avoid getting hurt).

See this passage:

Oh, and in so far as first year Hermione can be trusted to know such things:

It's possible, though we've seen it used as a high-pressure fire hose (putting out the fire in Hagrid's, Harry's attempt to put out fiendfyre with it) so it must be able to deyhydrate a fair amount of air, and dehydrate it completely, to be able to continuously pump out what may be hundreds of litres. In such a case it's strange that it's never described as changing the air.

 

See, this leads me to believe that there's a third fundamental form of enspellment that imbues an object with independent direction and purpose. It would encompass the way mirrors make commentary, how the Ford Anglia 'went wild' and how those chess pieces learn to be useful and/or cantankerous.

It's the part that changes a thread of magical creature wrapped in a piece of wood and turns it into a wand.

Is it programming or spirit-binding? However it functions, it's an aspect of magic that is being ignored, or assumed without being investigated.

 

In general, i always imagined that magic itself is semi-sentient, not completly though. so if you have places or objects that are subjected to a lot of magic they can develop life-like characteristics.

So if you heavyly (spelling?) enchant something, it can develop a character of its own over time, at least that's my head canon. For example: someone enchants a cloak with a waming charm and wears it regularly for 10 years because it's his favourite. Now someone steals it and puts it on, and the cloak gets so hot that he has to take it off. The cloak can't just come to life and walk away on his own, but within the scope of its abilities it starts to express a character, if you will. Its a lame example, but the best i could come up with so fast.

On the topic of animation charms:
I'd like to think that they are technically charms, and in lower years you learn simple animations that have exactly one effect, in charms class.

Animating something to be 'alive', however, is taught in Transfiguration.
We have to remember, that no magic can create ture life or bring the dead back.
I imagine that you have to concentrate on the character/personality you want to imbue as a whole. The animation therefore doesn't teach the object a specific behaivour but rather imbues a personality and enables general movement to express it.

Inanimate to animate transfiguration requires this animation to be cast simultanously, or you would just transfigure a lifeless body, and that is why it is taught in transfiguration.

hmm let me know what you think; does that make sense or is there a contradiction to canon somewhere?