Harrison Ford talks about a 5th Indiana Jones movie & decides to keep his "goddamn mouth shut" about if #4 was as good as #'s 1-3.

MTV:
MTV: A few months later, can you be objective about the film now?
Ford: I have two heads. I can go inside or outside the film. I think that's important for me to see it in an external way.
MTV: Does that external head think this one stands up to the other three films?
Ford: That external head has no mouth. That external head is smart enough to keep his goddamn mouth shut. [Laughs.] .......................
MTV: Steven Spielberg has said that another "Indiana Jones" adventure would only happen if the audience essentially asked for more. A worldwide box-office gross of nearly $800 million would seem to say there's still an appetite. Is a fifth "Indiana Jones" film inevitable?
Ford: I don't know. If we come up with a good idea ...
MTV: Is the ball in George Lucas' court at this point?
Ford: It is. That's the process. With some general input, he goes off and searches for the MacGuffin [Ed. note: That's the plot device that propels the story, i.e. the Ark] and then stumbles into a story. And at some point, we have a chance to take a look at it and give some input.
MTV: And he hasn't found the MacGuffin yet?
Ford: No, we're still in the primary stages.