Why on a dropped 3rd strike can the runner advance?

Beats me. Why is the sky blue?

The principle is refraction of light. The density of the atmosphere is greater than that of space. Light passes from a less dense to a more dense medium (space to the atmosphere) and is bent or refracted, breaking the light (4000-7000 Angstroms) into different colors, and as stated above, blue predominates. Now, the reason a batter can run to first on a missed third strike is that it is actually a catcher's potential error. The third strike represents the potential out, but since the catcher has so many chances during a game, he is charged with a passed ball instead of an error when a runner advances, and he is charged with a passed ball if he misses catching the pitch that would result in an out. Of course, if it isn't the catcher's fault and is the pitcher's fault, a wild pitch is charged to the pitcher. If a wild pitch results in a third strike, the batter can run to first since it was a pitch on which an out should have been recorded.

Huh?!

If an outfielder catches a fly ball, the batter is out. If he doesn't, the ball is in play and the batter/runner advances at his own will. If a catcher catches the third strike, the batter is out, if he doesnt, the batter/runner advances at his own will. Is the ocean blue for the same reason?