Laws of Physics
Laws of Physics
[Black Hat is standing on a ladder, holding a heavy ball attached to a line from above. Cueball stands beneath, where if the ball swings it will smack him in his upper body.] Black Hat: Okay, hold still. Black Hat: And remember, if you really believe in the laws of physics, you won't flinch.

Black Hat , being Black Hat, is deliberately perverting a classic physics demonstration. In the normal version of the demonstration, a heavy ball on a pendulum is pulled to one side until it is almost, but not quite, touching the demonstrator or volunteer's nose or chin. When the ball is released at rest, it swings down and away, then back up to (almost) the same distance in the arc from where it started — but never (by the laws of physics) farther than where it started. As long as the demonstrator doesn't lean in or push the ball, it's impossible for it to strike them. It's a natural instinct to move away or protect yourself if you see a heavy object moving quickly toward you, but confidence in the physics of the demonstration means there is no reason to flinch. ( Sample video. )
In this comic, Cueball is not standing at the beginning edge of the ball's movement, but rather at the base of its swing, meaning that the ball will strike him at its maximum speed. Presumably, Black Hat is entirely aware of this and is hoping that Cueball's understanding of physics is insufficient to see through this prank.  Judging from the "slack" of the rope, the ball should not hit Cueball in the head but could certainly hit him in a lower, and quite painful, place...
The title text refers to the fact when someone flinches during the pendulum experiment, they are commonly accused of not having faith in the laws of physics. Randall is rebutting this argument by stating that, rather than not having faith in science, he is actually in tune with it, specifically the biological processes that led to the flinch reflex. His eyes and his flinch reflex have been calibrated through millions of years of evolution. To instantly dismiss his body's natural reaction when a heavy object comes quickly towards his face does not give enough credit to these mechanisms that successfully kept him (and every one of his ancestors) alive. In other words, while flinching may indicate doubt of the laws of physics, it may equally well indicate trust in the laws of biology.
The idea of hitting someone else with a pendulum is also the topic of 755: Interdisciplinary and 2539: Flinch .
[Black Hat is standing on a ladder, holding a heavy ball attached to a line from above. Cueball stands beneath, where if the ball swings it will smack him in his upper body.] Black Hat: Okay, hold still. Black Hat: And remember, if you really believe in the laws of physics, you won't flinch.
