Is defeasibility necessary for scientific explanations?

Answer 1

Defeasibility is at most a starting point for scientific method, but is not the core. Defeasibility has a property in its definition that violates scientific methods. It contends that one doesn't need to prove a property stated in the scientific explanation is false, but that one only needs to prove that it is logically possible for an alternate explanation to exist.

This is only the beginning of scientific exploration. Once a potential for a logical explanation has been defined, scientific method requires that the alternate method be proven (or at least argued with significant experimental weight) not just logically reasoned.

Defeasibility is the errant path taken by UFO and Big Foot enthusiasts, who use "logical possiblity" as proof of existence.

Answer 2

Falsification? Not necessary to the explanation, per say, but explanations must withstand being falsified. Not all scientists are on board with Popper, let alone Kuhn.