Agreed, this is also a problem in economics (though even in economics there are some limited experiments that can be done). I think a key issue people overlook

Agreed, this is also a problem in economics (though even in economics there are some limited experiments that can be done). I think a key issue people overlook in this debate is the presence of a theory that makes sense. If you just plot data until you spot something that looks like a trend, or fit models until your F-test comes back significant or your R^2 is big enough, then yeah, you can't even make a good case for causation. But if you start with a reasonable theory that fits with existing knowledge, then you can at least make a case.