foul tip out

Question
Why is a foul tip into the catcher's glove an out on the third strike but not the first two? If a player foul tips a ball and it flies straight up in the air and is caught by the catcher, it is an out regardless of the number of strikes. What is the difference?

Answer
Andy,

The difference between the two is found in the Definitions section of the Official Baseball Rules (Section 2.00):

A FOUL TIP is a batted ball that goes sharp and direct from the bat to the catcher抯 hands and is legally caught. It is not a foul tip unless caught and any foul tip that is caught is a strike, and the ball is in play. It is not a catch if it is a rebound, unless the ball has first touched the catcher抯 glove or hand.

A FOUL BALL is a batted ball that settles on foul territory between home and first base, or between home and third base, or that bounds past first or third base on or over foul territory, or that first falls on foul territory beyond first or third base, or that, while on or over foul territory, touches the person of an umpire or player, or any object foreign to the natural ground.

The rules make a foul tip considered a strike, similar to swinging and missing the ball completely. The reason a foul tip on the third strike counts as as an out is simply because all caught third strikes are outs. If a foul tip is dropped by the catcher on any strike, the ball is foul.

I can't answer why the rules writers made the two different.