I have seen this stated more than once "Science is observation then measurement". It's not really how it works, it would be "verifiable observation". Science has no interest in measuring every non verified observation. ...
Verifying observations a priori isn't scientific though. We develop theoretical knowledge by observation, hypothesis and experimentation in that order.
Initial observation is how we come up with hypothesis in the first place. If you filter observation based on pre-existing theory you can't form new hypotheses. The science is in comparing the prediction of the hypothesis to the result of the experiment.
Of course, myths survive partly because falsifying non-existent things is tricky. I'm not going too far down that rabbit hole this morning.