Baptism consists of getting dunked or sprinkled. Which technique is used matters about as much as whether you pray kneeling or standing on your head. Dunking is a better symbol, however. Going under symbolizes the end of everything about your life that is less than human. Coming up again symbolizes the beginning in you of something strange and new and hopeful. You can breathe again.
Question: How about infant baptism? Shouldn't you wait until the child grows up enough to know what's going on?
Answer: If you don't think there is as much of the less-than-human in an infant as there is in anybody else, you have lost touch with reality.
When it comes to the forgiving and transforming love of God, one wonders if the six-week-old screecher knows all that much less than the archbishop of Canterbury about what's going on.