This argument is valid:
If no good theodicy can be given, some virtuous people’s lives are worthless.
No virtuous person’s life is worthless.
So, a good theodicy can be given.
The thought behind 1 is that unless we accept the sorts of claims that theodicists make about the value of virtue or the value of existence or about an afterlife, some virtuous people live lives of such great suffering, and are so far ignored or worse by others, that their lives are worthless. But once one accepts those sorts of claims, then a good theodicy can be given.
Here is an argument for 2:
It would be offensive to a virtuous person that her life is worthless.
The truth is not offensive to a virtuous person.
So, no virtuous person’s life is worthless.
Perhaps, too, an argument similar to Kant’s arguments about God can be made. We ought to at least hope that each virtuous person’s life has value on balance. But to hope for that is to hope for something like a theodicy. So we ought to hope for something like a theodicy.
The above arguments may not be all that compelling. But at least they counter the argument in the other direction, that it is offensive to say that someone’s sufferings have a theodicy.
Here is yet another argument.
That there is no good theodicy is an utterly depressing claim.
One ought not advocate utterly depressing claims, without very strong moral reason.
There is no very strong moral reason to advocate that there is no good theodicy.
So, one ought not advocate that there is no good theodicy.
The grounds for 8 are pragmatic: utterly depressing claims tend to utterly depress people, and being utterly depressed is very bad. One needs very strong reason to do something that causes a very bad state of affairs. I suppose the main controversial thesis here is 9. Someone who thinks religion is a great evil might deny 9.
