In chapter 7, the author says "Suddenly, the evidence overwhelmed me: there was no longer any reason to live, any reason to fight." Yet he turns around and pleads with his father to wake up, yelling "He's not dead! Not yet!" What explains Eliezer's contradictory feelings?

Even though he is starting to understand that there may be no sense in trying to survive the concentration camp because the threat of death is so close, he still is not ready to actively accept that by losing his father. When the guards see that he won't get up Eliezer doesn't let them take him, shouting that he isn't dead yet. It is one thing to think about and conceptualize death, but another entirely to have to face it physically.