Rather simplistic and naïve.
The difference between a duffer and a PhD theoretical Physicist is mathematics.
A theoretical Physicist cosmologist can test his theory with mathematical models. A sound cosmological theory will have a mathematical model that will confirm or disprove its possibility. If the mathematics determine that the theory is possible then a physical experiment can be designed to test the theory’s relationship to the real world.
A duffer would be hard pressed to design a mathematical model to demonstrate that the universe resides on the back of a turtle or any other theory he may dream up and be harder pressed to design an experiment to provide physical proof to backup that theory.
Simplistic and naive, maybe. I agree.
But I did say that the physicist knows the language of his trade. Maybe you didn’t understand what I was getting at, but that language IS mathematics.
I will disagree with you on one point: mathematical models will NOT always prove or disprove a theory. They will ten k to confirm or disconfirm, but the mathematics is always also subject to inspection and investigation. The history of physics is replete with theories once confirmed by mathematical models which were later shown - both the theory and the model - to be incomplete or inadequate.
My point was and is that cosmology is supremely speculative.
One of the fundamental problems with modern physics IMO is that they are chasing down the 'string theory' rabbit hole. String theory isn't even wrong, and pretty much can't really be tested.
the trouble is that something like string theory appears to mathematically beautiful to many physicists but it is neither prescriptive or descriptive of reality. That is, the math doesn’t describe any part of visible reality nor can the math be used to solve real life problems.