IGN关于主角无限的解释，有助于了解剧情，不用猜了

aeolos

from http://www.ign.com/wikis/bioshock-infinite/Booker_DeWitt
电脑自动翻译，不过也能看明白。

The Baptism of Booker

Although early on in the game it appears that Booker is in fact travelling to Columbia as a means to 'erase a debt,' this is merely a fabrication he has created in his mind as a result of being two different people across two different worlds.

Now hang on kids: this is where it gets confusing.

It is revealed at the game's climax that Booker is in fact Zachary Comstock. A pivotal moment in his life after the battle of Wounded Knee saw Booker about to be baptised in a river in order to purge him of the sins he commited during the fighting.

This results in the split. In one reality, Booker, the Booker DeWitt the gamer plays as, refuses to be baptised, and as a result goes on to become the main protagonist of Bioshock Infinite.

The second Booker accepted the baptism, became highly religous and changed his name to Zachary Comstock. This then led to the creation of Columbia, the abduction of Elizabeth from the other version of Booker, and the events of Bioshock Infinite.

It is revealed that 'AD' scar on the back of Booker's right hand stands for Anna Dewitt, Booker's daughter.

布克的洗礼
虽然游戏早期看来布克实际上是去哥伦比亚作为一种手段来“消除债务,这仅仅是一个制造他创造了在他脑海的结果是两个不同的人在两个不同的世界。
现在挂在孩子:这就是它变得混乱。
这是显示在游戏的高超,布克实际上是扎卡里斯托克。一个关键时刻在他的生命战斗结束后受伤的膝盖看见布克要受洗在河里为了净化他的罪他多渠道的战斗中。
这个结果在分割。在一个现实,布克,布克德威特玩家扮演的,拒绝接受洗礼,因此继续成为主要的主角生化奇兵无限。
第二个布克接受了洗礼,变得非常严厉和改名为扎卡里斯托克。这就造就了哥伦比亚,绑架伊丽莎白从其他版本的布克,事件“奇兵”无限。
据透露,“AD”疤痕的背面布克的右手代表安娜德威特,布克的女儿。