When Mitt Romney said he saw his father march with Martin Luther King, Jr., he didn't mean he saw it, he meant that he "saw" it... in the sense that if you close your eyes and imagine something, you can "see" it. Like, oh, visions of sugar plum fairies. That kind of thing.
Oh, you thought he meant it really happened? No, silly! It's a figure of speech! Figurative, you know? Like when you say something "is," but you don't mean that it is in real life, you just mean... well, it depends on what the meaning of "is" is.
Yeah. Like that.