The cleanest observation would be Everything is Correlated (https://www.gwern.net/Causality) and correlation is not a productive way of investigating the world.
If A causes B and B causes C then we can only say that A and C are correlated. If the average chain of causality is 4 long then the Bs outnumber the As and Cs.
Inductive (observation) evidence is more available than deductive (purely logical) evidence. Why limit yourself to only deductive evidence?
I don't have to resort to a chemistry lesson to convince you that drinking bleach would be very harmful, right? Can't I merely show you photos of bleach-bellied-corpses?
