A shallow intellect does not think, he only pretends to do so to impress others. Therefore, he will tend to say thinks he knows will impress those around him, like his Marxist professors.

A deep intellect thinks for the fun of it. He does NOT care what other people think about what he opines; he finds his way through his thoughts by logic and his experiences, not by reading the lips of others. He thinks for himself, in more senses than one.