> It can be fun to speculate but by definition it is impossible to know. I think the distinction is way more blurry than you're acknowledging. For example, the

> It can be fun to speculate but by definition it is impossible to know. I think the distinction is way more blurry than you're acknowledging. For example, the way we "know" what atoms look like is by technology like x-ray crystallography or scanning tunneling microscopes. In these cases, we're in no sense directly observing the atoms, were looking at correlated electric or photonic signals and using mathematical equations to infer what the atoms look like. In this case there truly is an "impenetrable barrier" to observation, instead of speed of light, it's wavelength of visible light. The amount of physics we cannot directly observe is much larger than amount of physics we can, without even getting into quantum phenomenon which we also cannot observe even in principal.