>>512699115
>retardation, you need an actual observation of something before you can conclude what it is or what it's made of
You don't need to see with your own eyes. You just need evidence.

>inferring something from readings from an instrument is an assumption at best, any intellectually honest person will tell you that
You can measure the size and thickness of something with sound (ultrasound for example)

>also, how would a seismograph that just measures the ground shaking be evidence of what's even 1km down?
Because earthquakes vibrate through the earth, like a loud bag in a large room.

The problem with people like you is that you deny measurements by means other than human eyes. That is why you fail.