In this argument, an atheist uses suffering in the world as an argument for God’s existence. He proposes that there is unnecessary suffering and that this demonstrates that God cannot exist because if God is omniscient, omnipotent, and omnibenevolent, then there should be no unnecessary suffering in the world. But since there is unnecessary suffering, then God must not exist. The argument fails for several reasons. 

An argument against God’s existence from unnecessary suffering

1. God is omniscient, omnipotent, and omnibenevolent
2. An omniscient being would know how to prevent unnecessary suffering
3. An omnipotent being would be able to prevent unnecessary suffering
4. An omnibenevolent being would desire to prevent unnecessary suffering
5. Unnecessary suffering occurs
6. From 2, 3, 4, 5: Therefore an omniscient, omnipotent, omnibenevolent being does not exist
7. From 1, 6: Therefore god does not exist

Refutation

1. God is omniscient, omnipotent, and omnibenevolent
2. An omniscient being would know how to prevent unnecessary suffering
3. An omnipotent being would be able to prevent unnecessary suffering
4. An omnibenevolent being would desire to prevent unnecessary suffering
5. Unnecessary suffering occurs
   1. How can it be established that unnecessary suffering occurs?
   2. What criteria would anyone use to establish what is unnecessary suffering?
   3. God can certainly have reasons for allowing suffering to occur in the world:
      1. As a demonstration of the effects of sin in the world.
      2. As a demonstration of the effects of rebellion against him.
      3. As a means by which sin is shown to be bad.
      4. As a means by which people can learn to depend on him.
      5. etc.
   4. Simply stating that unnecessary suffering occurs does not mean that it is so.
   5. Christian theology states that suffering is a result of sin in the world.  This is the result of Adam’s free choice and the effect of sin upon his descendants and the world.  All suffering is then the necessary consequence of this sin.
6. From 2, 3, 4, 5: Therefore an omniscient, omnipotent, omnibenevolent being does not exist
7. From 1, 6: Therefore god does not exist
   1. Since number five cannot be demonstrated to be true, the argument is not valid.