Gotta ask: is this gravity example real? You really have friends who have some sort of mystical commitment to the idea that gravity is somehow entirely epistemologically self-grounded?
Almost literally every physicist since Newton has believed that there is some sort of underlying theory which explains gravity. Its hard to imagine how anyone could get the idea that the matter was somehow settled.
Most people think we understand gravity better than we actually do.
To compare it to an actual hot-button issue, we know more about the mechanisms of evolution than we do about the mechanisms of gravity.
We know kind of how it behaves at various scales, but we don't know why it does. We don't know what makes gravity. Why do denser objects have more of it. Why is it weaker than other forces, yet felt on larger scales? Does it actually exist or is it an emergent property kind of like the centripetal force (or is it centrifugal, I keep getting those flopped)?
Almost literally every physicist since Newton has believed that there is some sort of underlying theory which explains gravity. Its hard to imagine how anyone could get the idea that the matter was somehow settled.
I'd love it if you could share more context.