From The Martial Arts Encyclopedia
Thornton's exact words on the subject are:
For something to be truly Alive in what we do, then it has have three key elements: Movement, timing and energy (resistance). If you are missing any one of these, then it is not Alive.
Movement means real footwork not contrived, not in a pattern; on the ground it means exactly that also: Movement. If the person is just laying there, not moving as you apply your lock or move, that is not Alive. In the clinch it's the same: Pushing, pulling, moving.
Timing is of course just that. If it's in a predictable rhythm, a pattern, a repeatable series of sets, then you are not acquiring or developing timing, just motion speed.
And of course energy. Swing the stick like someone would really swing it. Don't stop at centerline. Punch with the energy of someone who wants to hit you, not locking your arm out so your partner can look good doing the destruction, trap, silat sweep, etc.
You must move, have a sense of timing and use progressive resistance