Which living things merit our sympathy? Our pets? Certainly. What about human embryos? And plants? Is it consciousness or complexity or being human or the capacity for pain that makes an individual life worth our empathy?
The debate over animal rights has reinforced one ancient measure of an organism’s worth. An organism that shows signs of experiencing pain is said to be entitled to live without that pain. These sentient beings include cats and dogs and most of the animals that we eat or use for clothing or experiment on. Insects, with their minimal nervous systems, are on the margin of the sentience line.
Below the line are the simplest animals such as sponges and jellyfish, along with plants and single-celled bacteria and other microbes. These don’t experience suffering and have no awareness of a kind that we would recognize. They may have value collectively as part of the environment, but a single jellyfish or an individual plant has no standing for human commiseration.
Although I understand its role in the cause of animal rights, I find this sentience distinction unsatisfying. If an organism appears to be “feeling” a disease or injury, we give its condition more weight and urgency than we would if the organism—a plant, for example—were one that did not consciously experience such a condition. A tree may be attacked by insects or suffer other life-threatening conditions, but if we are accustomed to imagining the terror of a pig going to slaughter, we probably won’t empathize much with the stress on the tree as chemical messages sweep through it.
When we feel compassion for another being that is in dire straits, what are we feeling sympathy for, exactly? Is it for the possible loss of an individual life? Is it for the dangerous condition that is attacking the organism? Or is it for the pain that the organism is enduring? I think it is the last, if only because the evident pain in an animal reminds us of our own capacity for suffereing. Perhaps we should remind ourselves that non-sentient beings, though without visible torment, may struggle, crave, and weaken as relentlessly as sentient ones.
The uniqueness and persistence of life over 3.8 billion years endows all living things, both with and without awareness, with value. I’m not recommending the ludicrous extreme of not killing plants; we, like all animals, can not survive without eating other living things, either plant or animal. But I am suggesting that we heighten our awareness of the sentience distinction that cleaves the living world in two and can diminish our connection with non-sentient life.