Corrected entry: The whole time Sam is a ghost, he is trying to touch things but can't supposedly, until the ghost in the subway shows him how. But during that whole time that he couldn't touch things, Sam could still go on the subway, (he would be able to jump through the subway doors, but would not fall through the floor when he landed) sit on couches, (he would sit on the couch, the cushions would move, but I'm sure if he tried to move the couch he wouldn't be able to) go up stairs, etc. It was a major part of the movie that he could not touch things, yet, he was touching things the whole time.
Phixius
5th Nov 2002
Ghost (1990)
Correction: If that's the case then why is it that right after he died he tried to touch his own face but couldn't? He had been touching things his whole life so it should have been second nature.
Correction: In the DVD commentary, the director explains about believing that as a ghost you can do something easy that you always did when you were alive such as walk up steps and sit down. Its all explained in the commentary.