Consider the following three arguments against free will and justice in Christianity and similar religions:
Imagine that God, an omniscient being, has just appeared and told you what you will do 30 seconds from now. Suppose that it is something trivial and thus easily avoidable, e.g. you will eat a sandwich. Now assume that you have the desire to exercise your free will and change the future. There are only two possible outcomes:
1.) You eat the sandwich.
2.) You do not eat the sandwich.
If you do not eat the sandwich, you have proven that God does not know the future.
If you do eat the sandwich despite your stronger desire to prove your free will, you have proven that you do not actually have free will.
Therefore, human free will is incompatible with God’s omniscience.
The only way around this problem is to claim that omniscience refers to total knowledge of the past and present, but not the future, which has not yet occurred. This is perhaps akin to adjusting omnipotence to mean “the power to do anything that is possible” instead of “the power to do anything.” However, if God is ignorant of the future, then religions in which God’s knowledge of the future is essential cannot be true.
Premise 1: The human lifespan varies from individual to individual.
Premise 2: Humans grow up in different conditions and with different genetics.
Premise 3: Humans develop different standards for truth.
Premise 4: An individual has no control over premises 1 and 2 and has only limited control, if any, over premise 3.
Premise 5: Christians often claim that humans can only find salvation through faith in God.
Conclusion 1: Therefore, it is not fair that human lifespans, conditions, and standards for truth vary. (Some people die much earlier than others, who therefore have more time to find salvation. Some people are born into conditions where the Bible is absent or even criticized while others are born into conditions where the Bible is present or even praised, which makes it easier for them to find salvation. Some people have a higher standard for truth than others, who therefore find it easier to accept the Bible and thus to find salvation.)
Premise 6: God has control over these factors.
Conclusion 2: Therefore, God is not just.
Premise 7: Christians claim that God is just.
Conclusion 3: Therefore, Christians (and those who share such beliefs) are wrong about something. Either God is not just or there are other means of finding salvation.
Premise 1: It is only really fair if God gives each individual enough time and the right conditions to find salvation. (One man might have found salvation if he had just lived one more day. Another might have found salvation if he had been born in a different country.)
Premise 2: God is fair. (A common Christian claim.)
Conclusion 1: Therefore, God gives each individual enough time and the right conditions to find salvation.
Premise 3: People who can find salvation would find salvation if given the time and conditions that would lead to salvation.
Premise 4: Some people do not find salvation.
Conclusion 2: Therefore, some people could not have found salvation in any amount of time or under any conditions.
Conclusion 3: Therefore, some people are predestined to be punished.
(I can imagine challenges to premise 3, but not good ones.)
Implications for Ethics
If humans do not have free will, then it is unjust for God to reward or punish some, but not others–or to punish anyone at all. This should be indisputable even among the religious unless they believe that God also lacks free will, in which case justice cannot apply. Without free will, the entire project of ethics is a sham.
If God is unjust or does not know the future, then God is not fit to deal out eternal reward and punishment. Some of the religious may argue that God is fit to do so by virtue of being Creator or omnipotent, but this is a very unsatisfying answer for those of us who do not define what is good by the imperfect or even arbitrary decisions of a single being.
I credit John Myste with the inspiration for and contributions to arguments 2 and 3 through his recent post, Sunday Inspiration. I also credit him with any logical inconsistency found in this post.