Eight, if one is a former Madison Avenue ad man, another knows how to make a YouTube video and the others have honest faces and stage presence.
Better than perhaps any living American, he knows that courage on the front line is one thing, and on the campaign stage quite another, knows how tiny and harmless the seeds of fanaticism can seem, how one cry of "kill him" can crescendo into a chorus that can't be stifled.
But it is one thing to have seen the land, and another to know how to work it.
Receiver Wayne Chrebet said the players and the coaches are still getting comfortable enough with one another to know how each will react in game situations.
"It is one thing to be an expert in your field and quite another to know how to convey that knowledge to a class of 30," she said.
The thing is, with love, it's one thing to love and then it's another to know how to love, and maybe we take a lifetime to learn".
Sometimes it helps to let another person know how you feel.
It is one thing to know that the evidence shows that improving hand hygiene reduces the transmission of infection but obviously quite another to know how to get a hospital staff to wash their hands more frequently.
Get married because you have gotten to know one another, and you know how each other clicks, and you know how to love one another in a real and practical way.
Another did not know how to start his car.
