According to William Hasker, the existential problem of evil occurs when “theism is questioned and/or rejected on the basis of moral protest, indignation, and outrage at the evils of this world.” Hasker claims that if I am glad that I exist, then I cannot (reasonably) protest against God. The simple version of his argument is:
(1) I am glad that I exist.
(2) If I am glad that I exist, then I am glad that the history of the world is the way it is.
(3) If I am glad that the history of the world is what it is, then I cannot reproach God for the general character or the major events of the world’s past history.
(4) Therefore, I cannot reproach God for the general character or the major events of the world’s past history.
(1) is based on an assumption. Hasker asks us to think for a moment. On the whole, do you prefer that you exist rather than not? If so, then proceed.
(2) is based on a thesis about human identity. Hasker argues that you being you is contingent on an incredibly complex history which leads to the exact sperm and egg joining and leading to the formation of you. If history had been different, then you would probably not exist: “a human being is initially individuated by his body, so that, had that body not been conceived and born, that particular human being would never have existed.” Had major or significant events in the world’s past history been different than they were, then in all probability neither you nor the persons whom you love would never have existed.
This claim is acceptable to all who hold to a mind-body thesis such as: (i) I am my body (ii) my body is necessary and sufficient for the existence of “me” or (iii) my soul is created as the soul of this body. However, this claim is not acceptable to those who hold to the thesis that I am identical to my soul. If you are identical to your soul, then you could have been in a variety of different bodies and so could exist if the history of the world had been different. If you are a Cartesian dualist, then you do not have to follow the rest of the argument.
Hasker then argues that to be glad about something entails that you cannot be sorry about it at the same time. If you are glad out it, then you prefer it. You cannot prefer and not prefer the same thing at the same time: “my being glad that P entails my preferring that P be the case rather than not-P. Conversely, I am sorry, or regret that P, this means that I would prefer that not-P be the case rather than P.”
Consequently, Hasker argues that if you am glad on the whole that P, and you know that P entails Q, then you rationally must be glad on the whole that Q. Or put a different way, if are glad on the whole that P, and you know that if Q did not obtain neither would P, then you rationally must be glad that Q. Crucially, this means that if you are glad on the whole about your own existence and that of those whom you love, then you must be glad that the history of the world, in its major aspects, has been as it has.
If you are glad about the history of the world, then, says Hasker, you can't reasonably complain to someone about it. So, Hasker concludes: "If I am glad on the whole about my own existence, and that of persons close to me, then I cannot reproach God for the general character or the major events of the world’s past history."
Here are some objections:
First, you could deny the human identity thesis. A dualist does not depend on the very sperm and egg that joined and you could be you if a different sperm and egg joined. You are identical to your soul and God could have created you in any body he wanted.
Second, one could argue that it would be reasonable to express moral outrage to God even if you are glad that you exist if and only if anger and complaint to God for the major events of past history is an evil that God allows in order to produce a greater good. The greater good, in this case, might be greater knowledge of God, cathartic outcomes for the sufferer, or closer, more intimate relationship with the Lord. The argument could run like this:
a. Anger and moral outrage against God is an evil (and thereby irrational)
b. God allows some evils for the sake of greater goods that are logically tied to those evils.
c. It is not possible to have a certain kind of knowledge, cathartic experience or relational closeness without anger and moral outrage against God.
d. Therefore, God is morally justified in allowing anger and moral outrage against himself.
Third, one could argue from rationality in the other direction, somewhat like this:
a. It is always rational to agree with God
b. God is morally outraged at evil
c. I am rational to be morally outraged at evil
This argument helps one find a place for moral outrage but not for complaint to God. But one could argue on the basis of the Bible that moral outrage can be directed at God only if the grounds for complaint are found within the divine nature. Job, David, Jeremiah and many a prophet bring their complaints to God in crisis. They do not confront God in a way that places God in the dock. Rather, they appeal to God's own nature for his help in times of trouble. Their words are divinely sanctioned complaint and can operate like a script for our own lament before God.