“Where does suffering come from? Why do we suffer?” The questions open biologist Ursula Goodenough’s essay “The Biological Antecedents of Human Suffering” (in The Routledge Companion to Religion and Science (2012)). Through the ages, people have looked to religion for the answers, with no easy satisfaction. But under a biologist’s eye, the questions look more manageable.

Goodenough proposes two categories of suffering, the biological and the experienced. Biological suffering comes to all living things. Bacteria, plants, and people all seek out what they need—water, food, light—and withdraw from what harms them—poisons, enemies. Any organism with too little of what it needs or too much of what will weaken it, is struggling.

The Four Horsemen of the Apocalypse by Albrecht Dürer  (sciencemediacentre.co.nz)

For animals with developed nervous systems, however, such suffering not only occurs biologically but is also experienced. The biological struggle announces itself through the nervous system. Vertebrates (with a backbone, head, and skeleton) carry neurons called nociceptors in their skin and internally in muscles, joints, and the gut. When nociceptors tell the brain that something is very wrong, the brain interprets the message as pain—a slice in a finger, a twisted ankle, sudden nausea. In addition, for humans—social creatures that we are—the sources of such experienced pain include social and psychological feelings (envy, guilt) as well as bodily injury.

Fortunately, for most of the difficulties that organisms endure, antidotes are available. Organisms will move towards water if they need it, try to compensate for an injury, muster immune responses to fight infections, call a friend if they are lonely. Goodenough calls these corrective measures amelioration systems; they make things better.

But often at a price. We humans may feel the amelioration process as more uncomfortable than the adversity that triggered it, at least at first. We suffer through a fever because the higher body temperature strengthens the immune response to an infection that might otherwise be barely noticeable at the start.

No matter their inconvenience, though, amelioration systems are indispensable. To paraphrase Goodenough, organisms whose amelioration systems fail to cope with adversity will die. Organisms whose amelioration systems are inactive because they have all they need enjoy well-being. But it is organisms whose amelioration systems are at work “actively dealing with difficult circumstances” that are in a state of biological suffering.

Sometimes the suffering is not felt: “The food-deprived amoeba or the bacterium, the plant plunged in darkness or subject to a wound, pays the suffering price, but does not feel the price.” In other cases, for humans and other vertebrates, the price is acute pain. Pain alone won’t ameliorate a condition but calls attention to it—and may teach a lesson that brainy creatures can remember about what they should do differently next time.

In other cases, though, continuous or recurring pain is a scam. Chronic pain is “physical pain that is not obviously in the service of amelioration systems and is unresponsive to analgesics or other practices….Here we encounter an example of things gone awry.” With chronic pain, “Suffering has become uncoupled from resolution.”

Goodenough closes, “The long evolutionary view of suffering is that it is an inherent feature of life….[It] is part of the package, the price paid for the gift of being alive at all.” Up to a point, we knew this already—that at least some suffering goes with being alive. But Goodenough’s naturalism presents suffering in an earthly mode, with less mystery and without guilt. Still, we are left to reckon with the irony that often what we suffer from are the very processes by which the body goes about repair and renewal.

These highlights amount to only a partial summary of Goodenough’s rich essay, which can be found  here at Google Books.