Here is my undeveloped suggestion with regard to pain: Pain is bad, among other things, because pain can make meaning disappear. Pain can confine us to ourselves and either make everything look meaningless or make it impossible for us to see anything else accept the pain itself—sometimes this comes to the same thing.
The thought that this might be the case occurred to me once in the shower. I was probably thinking about something when a shampoo bottle fell on my toe. It was as if time stopped for a moment or two. I could not think of anything else. It was as if my mind was extracted from my body. Nothing else existed in my world. I was completely absorbed in the pain, in my toe. The pain was my world. I was my toe. (An excellent discussion of closely related issues—in particular of how pain can isolate, perhaps even create a kind of logical isolation—can be found in Karen Fiser’s “Privacy and Pain.” Also important in this connection is Jean Amery’s discussion of torture in At the Mind’s Limits.)
Now, there is a claim to be made for the idea that we have a duty to find meaning in things. So, for example, it would be a deep moral failing—a deep blindness—to fail to find any significance in the fact that one has become a parent. We don’t only have a duty here. We have a strong natural tendency to find certain things meaningful—it is part of what being human is. It comes out in the fact that we keep pictures in our wallets, that we can feel sorry for a trampled flower; it certainly comes out in our tendency to look at ambiguous pictures, and try to see what is in them—imagine. We, humans, are compelled to do it sometimes; but this is not the kind of thing a dog or an elephant would to. And when we fail sometimes to find things meaningful—this can be comical or horrible—the failure is a blemish on our very humanity.
It is the same kind of odd blindness we find sometimes in Bentham or Hume. The latter, for instance, asks in his essay on Suicide:
It would be no crime in me to divert the Nile or Danube from its course, were I able to effect such purposes. Where then is the crime of turning a few ounces of blood from their natural channel?
We want to slap some sense into the writer of those words: The person in this example is not “turning a few ounces of blood from their natural channel.” Nor are they spilling some blood on the floor; they are committing suicide for crying out loud!
If indeed such duty exists to find things meaningful, then pain has a tendency to undermine it. It can suck the value out of things, and make their significance vanish. The whole structure of a human life can crumble in the face of pain. Pain may prevent us from seeing. In the presence of pain we may only be able to see as a Hume would: meaningless insignificant facts. Pain, that is, can have the same blinding effect on us as moral-intellectual laziness, or as some abuses of empiricism and utilitarianism.
By the way, in the spirit of this suggestion, it is possible to say that if pleasure is any good, it is so, among other things, because and insofar as it can open our eyes to things beyond us: Pleasure is good because it can be a flashlight that reveals to us something significant, or even meaning that we could not have fathomed before.