Theory and evidence is about not being able to accept a theory until there's experimental evidence to back it up. For example, the Aether theory was accepted, until experimental attempts to find it (eg. MM experiment) repeatedly failed. Then you have Einstein's theory of relativity, which at the time it was 'invented' couldn't be tested, so other physicists of the time were hesitant to accept it.
Eventually when we had technology like jets and atomic clocks, detectors for muons, particle accelerators, etc. we could test Einstein's theory, so now it's been accepted and there's no need for the aether.
The other one is about Einstein's thought experiments; they are valid and logical, but limited because they don't reflect something that 's possible in reality. Eg. the one about the light in the train, it's not really possible to have a train going at .9c, or to have someone able to observe the train if it were going that fast.