if something is caused by something else, then that something else will happen first before that something
else is river. first_cause is causal_agent. change is when_one_thing_becomes_another_thing. else is not river. sending is not causing. space is not what_between_else. beginning is not first_thing. change is not when_one_thing_becomes_another_thing. sending is causing. first_cause is not causal_agent.