Physiological changes in the body/brain consistently assosiated with said self-reported state.
>Of mathematical formulas?
We can reproduce most of their results with physical objects (adding 1 and 1 rocks makes 2 rocks, the shortest line between two points we can draw with less ink on a piece of paper is the straight line, in a sphere it's the geodesic and it indeed saves planes gas, and so on...)\
>Of radio waves?
Err, plenty of visible proofs of radio waves. You can very easily scan a room with a portable scanner, not to mention we hear the sound they carry.
>Where is the tangible visible obvious proof that the earth is not flat?
Photographs from space?
>Where is the tangible proof that your life has any future that makes any sense for you to get up in the morning and do any work?
Physiological changes in the body/brain consistently assosiated with said self-reported state.
>Of mathematical formulas?
We can reproduce most of their results with physical objects (adding 1 and 1 rocks makes 2 rocks, the shortest line between two points we can draw with less ink on a piece of paper is the straight line, in a sphere it's the geodesic and it indeed saves planes gas, and so on...)\
>Of radio waves?
Err, plenty of visible proofs of radio waves. You can very easily scan a room with a portable scanner, not to mention we hear the sound they carry.
>Where is the tangible visible obvious proof that the earth is not flat?
Photographs from space?
>Where is the tangible proof that your life has any future that makes any sense for you to get up in the morning and do any work?
There's none, since that doesn't exist.