they could have use some evidence to get this theory.
let's say that the scientist wanted to prove that air didnt exist. you cant see it. that's proof that it maybe doenst exist (of course air exists...I think).
A good theory in the theoretical sense is (1) consistent with empirical observations; is (2) precise, (3) parsimonious, (4) explanatorily broad, and (5) falsifiable; and (6) promotes scientific progress (among others; Table 1.1).
