> That's fine. Many public policy advocates throw around the term 'settled science'. But based on what you said, is there such a thing?

Yes, there is. Just because there is no absolute certainty, doesn't mean it's all just baseless speculation. Just because, as a matter of scientific methodology, atomic theory is not absolutely certain (i.e., we could hypothetically find evidence that contradicts the model), doesn't mean someone just made it up and it has no predictive power.