This video infuriated me- not because it was trying to prove that God exists; everyone is entitled to his own beliefs- but the method it used to argue the case.
This is a shining example of a straw-man argument. While this device sometimes convincing, especially against the gullible, it carries no factual weight whatsoever.
In order to properly explain, and to avoid sounding like a hypocrite, I am going to have to assume two things:
1. That this actually happened, which I doubt. Educators aren't supposed to force their religious beliefs on students, and this professor supposedly worked at a prestigious university.
2. That a god exists.
So, the professor says that God could stop the chalk from shattering on the floor. The first thing that hits my mind is Why should He? Why should God care; He is probably more concerned with starving children in Africa at the moment, and why would He listen to a non-believer anyway?
Enter the straw-man. If the chalk breaks, God doesn't exist. The professor could just as easily say, "I am going to ask God to turn my hair purple on the count of three. If my hair doesn't turn purple, God doesn't exist." That sounds a lot more preposterous, doesn't it? But the point is, it's the same thing. And we know perfectly well that it probably won't happen. (Try it. I know you're dying to.)
You can't tell me other students didn't pray before and didn't believe after that class. Many students didn't want the chalk to break. And yet, it only stayed intact one time.
It's very possible that the chalk slipped. The professor was angry, after all, and chalk is a rather slippery substance. If instead the professer had used the example I gave, and his hair turned purple, I wouldn't know quite what to think, as peoples' hair doesn't spontanously turn unnatural colors- it eliminates the chance of error. And why did God choose to listen to that one student and not the others?
Towards the end of the video, it says that there are two things you can do: to ignore it, or to pass it along to your friends to restore their faith. I chose the unwritten third- I chose to think.