The Problem of Evil (why is there so much suffering in the world given an OmniGod?) is sometimes answered by theists that suffering has to exist so that people have a working knowledge of what bad or evil is in order to know what good is, or indeed that pleasure cannot exist without pain.
This is obviously problematic for a number of reasons. First and foremost, if heaven exists, and there is no pain or suffering there, and this is actually supposed to be the paragon, the goal, of existence, then such a Problem of Evil paradigm is incoherent. This issue is set out here in “Free Will, the Problem of Evil and Heaven“, an older video of mine:
Firstly, we have the issue of heaven, then. It is apparent (supposedly) that meaningful existence can take place without the reality of pain or suffering. This alone invalidates the theodicy as being coherent.
Secondly, I can experience good health without having to experience bad health, such as debilitating disease. The counterpoint here might be that I need some working experience, first hand or otherwise, of suffering to truly appreciate goodness or pleasure.
However, this leads on to a further problem. The sheer volume of suffering seems to cause problems for this theodicy. Think of all the diseases in the world, the 2004 tsunami, the earthquake the other day in Nepal… is there any necessity for this massive quantity of suffering?
Related to this is a third problem: the connection of good to evil, as discussed by John Loftus in his superb book Why I Became An Atheist (2nd ed.), p. 236:
Besides, if suffering is needed to experience pleasure, then wouldn’t it follow that the more we experience suffering the more we could experience pleasure? Does it follow then that Holocaust survivors are better off having suffered since they can experience more pleasure afterward? And would this mean we should seek to experience more pain? Does that sound rational? Sadly, there are those who suffer through horrible, short lives and then die without any pleasure at all. What about the need to experience more pleasure in order to experience more suffering, which in turn would allow us to experience more pleasure, and so on? And how does this apply to the sufferings of animals?
We seem to have a terminal problem for this theodicy. A theist might argue that it should not be use don its own, but part of a cumulative theodical case to answer the problem of suffering in the world. However, these criticisms invalidate it from being used at all.
First, if heaven exists, then the theodicy is incoherent. Second, the amount of suffering seems to be vastly more prevalent than that which would be needed to do the job of being the foil for goodness. Thirdly, it should follow that the more suffering there is, the more goodness there is, to a proportional amount.
So this theodicy is riddled with issue.