What's Intelligence?

Joe and his buddy Jim are digging a ditch, while their foreman sits on a lawn chair in the shade, drinking lemonade. It's a hot day, and Joe starts wondering why the foreman isn't doing any of the work. "Hey Jim?" he asks. "How come we're down here digging the ditch, and the boss is up there, drinking lemonade in the shade?" "Iunno..." Jim replies, and they go back to digging.
After a while, Joe decides he needs to know. "I'm gonna go ask him." He climbs up out of the ditch and goes over to the foreman. "Hey boss? How come me an' Jim are down there diggin' the ditch, and you're up here drinkin' lemonade?"
The foreman looks at Joe, and says "Well... because I have intelligence, and you don't." Joe scratches his head for a moment, then asks, "What's intelligence?" The foreman considers this, and says "Well, let me give you some." He holds his hand up in front of the trunk of a big oak. "Hit my hand as hard as you can."
Joe shrugs, rears back, and swings. At the last moment, the foreman pulls his hand out of the way, and Joe punches the tree instead. "What'd you do that for?!?" he cries. The foreman smiles. "I just gave you some intelligence."
Joe heads back into the ditch, considering this. After a while, Jim asks him, "So what did he say?" Joe says, slowly, "He says it's because he has a lot of intelligence... and I have a little bit of intelligence... and you don't have any intelligence at all." Jim asks, "What's intelligence?" Joe replies, "I'm not really sure, but he gave me some, and I'm gonna give some to you."
Joe holds his hand up in front of his face. "Hit my hand as hard as you can..."