Being in transition is a very common state of affairs when viewed on an appropriate timescale, despite the rigidity of some of our conceptual frameworks. Things change over time; they evolve; they die. A system is reordered by an external disturbance; it shifts and causes another system to change in turn; this is the normal state of material existence. Living beings adapt and change, or become extinct, giving rise to new forms of life. Matter and energy continue their eternal dance.