sentences: if something is caused by something else, then that something else will happen second before that something
docs: second_messenger is tangible_thing. second_order_logic is predicate_logic. sending is causing. else is river. latter is second. sometimes_change is good_thing. change is when_one_thing_becomes_another_thing. space is what_between_else. putting_onto_else is putting. familiar_if has experienced_before