This is an absurd argument. At the very least, science can absolutely provide conclusive evidence that the world is not flat and that vaccines cannot cause autism. This isn’t a “belief.” This can be shown with clear conclusive evidence. Religious beliefs cannot be tested due to how they are structured (“just gotta have faith”).

So even assuming you are arguing in good faith, an anti-vaxxer and/or a flat-earther are people who can be shown irrefutable evidence that goes against their beliefs and they will simply close their eyes, plug their ears, and scream and shout until you go away. The opinions of those people are ones I don’t care about or think worthwhile because they have already made up their minds and are working backwards to look for evidence that supports their beliefs, and invalidating all others.