Yep. Too far down this road, and you arrive at Wolfram's observation that, hypothetically, the entire universe could be a simulation running as a cellular automaton with a single updating agent stepping the state of the universe interaction-by-interaction. It could take an arbitrarily-long time to run one "step" of the universe in that agent's timeframe, and life existing in that universe would have no way of knowing, because all of our processes for measuring time await the touch of that updating agent to progress.