Thornton's "aliveness" argument is in contrast to TMA's "fixed" kata-based training method - IOW "dead" - since anything that does not evolve/adapt to change is dead - or ends up dead.
Since we all know kata is merely a teaching/learning framework, and is not a true representation of actual combat, the "aliveness" argument is essentially a strawman.
Everyone knows (or should know) that kata is for all intents and purposes "ritualized" movement/combat - for reasons already outlined. One obviously doesn't "fight" using rigid kata movements, or in the rigid sequence imposed by embusen. Obviously, adaptation and change is implicit in everything we do.... unless one is such a noob as not to see that.
I've had this very vocal debate with some ppl on FA.com years ago. To suggest that there is no such thing remotely resembling kata in what Thornton does is ridiculous. How else would a noob otherwise learn basic technique? And to which I never got a straight answer from the "aliveness" proponents.