Thomas,

Your friend doesn't know Christianity very well. His argument is against a straw man.

I can't exhaustively go into all of these points, due to lack of space and competency on my part, but let me touch on them:

1. The scapegoat solution, or the premise that the guilty can be pardoned by the death of an innocent.
   
   This is not what Catholicism believes. There are some fundamentalists who believe this but they are not intellectually rigorous. I personally derisively call this the Divine Child Abuse Theory of Atonement . . . the idea that Jesus experienced all the full punishment of Hell on our behalf so we (the Church, His Bride) don't have to. It's like a father who whips his son when his wife displeases him. This was originated by John Calvin.
   
   The prevailing theory in the West is called the Anselmian theory, advanced by St. Anselm. It goes like this: Because God is infinite, a sin against his an infinite offense against His honor, and so requires that an infinite being atone for it (atonement literally means at-one-ment or reconciliation). I am not competent to go into the details of this theory. I'll leave that to my colleagues. There are other theories of atonement.
   
   
2. The notion that in order to forgive sins, God had to sacrifice Himself to Himself.
   
   To say that God in the Person of the Son sacrificed himself to God in the Person of the Father is fine to say as far as it goes but by no means was it required. God could have forgiven our sins just by metaphorically waving His Hand. He was not obliged, in other words, to sacrifice His Only-begotten Son. He did so however to demonstrate his love for us. (Romans 5:8). It's like a soldier who volunteers to go to war to save his country; he doesn't have to do it, but he does so out of patriotic love and dies for his country willingly. That's love. It's one thing to wave a flag at a Fourth of July or Veteran's Day parade; it's another to sign up and die.
   
   The comments about Himself to Himself deserve comment. They seem to suggest either a misunderstanding of the Trinity or a willful disingenuity about the question. God is three Persons in one God. It's more like a son sacrificing himself for his father than it is you sacrificing yourself for yourself. There are multiple persons involved.
   
   To say it's God sacrific[ing] Himself to Himself makes it sound absurd when the notion of one person sacrificing [to/for] another person is not absurd.
   
   
3. You must believe that God sacrificed Himself to Himself in order to obtain salvation; failure to believe this absurdity results in eternal torment.
   
   Some forms of Christianity do insist on this point but Catholicism doesn't strictly do so (and this is AskACatholic.com, not AskAFundamentalist.com). While it is essential in Catholicism for someone to accept and believe that God the Son offered Himself (presumably to His Father) on our behalf, to be saved, it is possible for those who do not know this — who are ignorant of the concept — or even who merely have insurmountable difficulties accepting it, to also be saved.
   
   
4. That Jesus' death qualified as a sacrifice. Real sacrifice entails real loss. Jesus didn't really die, nor did he suffer any permanent loss.
   
   
   • So where is the sacrifice?"
   
   He doesn't consider being:
   
   
   • seized
   • jailed
   • humiliated
   • whipped and scourged
   • crowned with thorns
   • smitten on said crown with thorns digging deep into his flesh
   • being pressed to carry the instrument of his execution to the place of execution in those conditions
   • being nailed to a cross
   • suffering excruciating and exquisite pain for six hours while being exposed naked before the elements and mockery of those around him
   • suffering fear of death and death itself for three full days to be a sacrifice

   just because he rose from the dead suffering no permanent loss. I sure hope he doesn't discuss this question with a veteran (especially a Marine!) Even opening a door for a woman is a sacrifice that entails no permanent loss but it's a sacrifice nonetheless.

   Life is full of real sacrifices that have no permanent loss. I'm not sure what he means by Jesus didn't' really die. Just because He rose from the dead doesn't mean he really didn't die.
   
   Jesus was not merely divine; he was also human which means he experienced pain, fear, and emotions like we experience them. The Passion is called The Passion because it wasn't a cakewalk for Him even though He was God.

By the way, given that Jesus never returned to his ordinary life, one can certainly argue that He suffered loss, even if one argues that the Resurrection negates the suffering value of the Passion.

Hope this helps,

Eric