There are things for which we see no plan or purpose but which we are convinced must have one. Suffering is the paradigm case since it forces the problem of meaning on us, but any action beyond a living being acting for an obvious good has a meaning/plan/ or purpose very much hidden to us.
Inability to find meaning is logically explosive, since any supposed meaning that cannot stand in the face of suffering is no meaning at all. Again, our own plans are too implicated in natural processes to keep their meaning when nature is seen as without one. The cycles of grief, for example, can be seen either as meaningful consolations or as proofs that nature is resilient and adapts itself to suffering. Taken in the first way, they are seen as insights into a deeper purpose, taken in the second way the happier part of the cycle is seen as proof that love is something that nature can easily dispense with. But very little of even the meaning we make for ourselves can survive a belief like that.
Greater plans or meanings commit us to an intelligence beyond ourselves who is involved with the world and working in history. Suffering and evil, or the weather-like flux of nature are thus better seen as demanding a judgment from us about God. Evil is not evidence we need contrary evidence for – the whole question is what judgment we will level in the face of the pointlessness of evil and our total repugnance (including our intellectual repugnance) to meaninglessness. Theodicy and the various responses to the problem of evil largely miss the point. We agree over who and what is required if things are purposive. Our disagreement is whether love is stronger than death, or the reverse.