I invite you to ponder on the etymology and actual definition of the word "null". It does not refer to some antecedent or to some notion of "reason", it refers

I invite you to ponder on the etymology and actual definition of the word "null". It does not refer to some antecedent or to some notion of "reason", it refers as explicitly as possible to "not-x", contra whatever effect generates "x". You are conflating the construction of the null hypothesis with a more liberal notion of hypothesis testing (science) per se.