Hi!
So, the parent believes that in a fast moving train, objects fall
slower that if the train would stand still!!! (Because any fool can
see that the object would have some initial horizontal velocity.)
Comments: 1) don't rely on observations by fools. 2) I personally
like "gedankening", but I agree with Ludwik that it does not substitute
for real experimentation. It just checks logical consistency of our
thoughts.
Emilio