This kind of demarcation usually hints that you are dealing with a subject that is not as concrete as you had supposed. "Science" doesn't really have a concrete

This kind of demarcation usually hints that you are dealing with a subject that is not as concrete as you had supposed. "Science" doesn't really have a concrete definition, a pseudoscience just means stuff that is pretending to be science. Remember that scientists existed before philosophy of science, including formalisations of The Scientific Method. Darwin wasn't following the scientific method, the method followed him.