 Second, the definition requires the causally dependent events to be distinct from each other. Distinctness means that the events are not identical, neither is part of the other, and neither implies the other. This qualification is important if spurious non-causal dependences are to be ruled out. (For this point see Kim 1973b and Lewis 1986b.) For while you would not have written ‘Larry’ if you had not written ‘rr’; and you would not have said ‘Hello’ loudly if you had not said ‘Hello’, neither dependence counts as a causal dependence since the paired events are not distinct from each other in the required sense.