Outline:Notes on the idea that plants are sentient and have feelings

• Context
  • This objection is not presented out of a concern for plant happiness but instead:
    • As an accusation of inconsistency.
      • "You don't really care about all sentient beings, only animals."
    • Implicitly as a reductio ad absurdum.
      • "So we can't eat plants or animals now? We must eat something. Since plants and animals are both sentient, it doesn't make any difference which we eat."
  • Provocative clickbait titles do not engender credibility.
  • The "Extra" node of this outline presents two weaker arguments often used by advocates and explains why they are weak.
• Plants differ from animals in ethically significant ways.
  • Plants cannot feel pain.
    • Plants lack a brain, a central nervous system, and pain receptors.
    • Plants may know they are being eaten via mechanoreceptors, but they don't care.
      • According to Daniel Chamovitz, Dean of Life Sciences at Tel Aviv University:
        • Plants have nerve-cell pressure receptors (mechanoreceptors), not pain receptors (nociceptors).
        • "Plants can feel themselves being eaten—they just don't have the capacity to give a shit."
        • Source
  • Plants cannot experience emotions.
    • Emotions are processed in the hippocampus and amygdala regions of the brain—neither of which are present in a plant.
  • Plants have no self-awareness or sense of the future.
    • Thinking requires a brain, and without thought, there can be no self-awareness or sense of the future.
  • Plants do not have desires, preferences, or interests.
    • There is no evidence that plants have the cognitive ability to have these traits.
• You kill many more plants by eating animal products than by eating plants.
  • Animals are inefficient at converting plants to edible animal matter.
    • This inefficiency is in part because of the calories expended for metabolism as well as the calories and food that go into producing nonedible parts, such as bones, cartilage, feathers, fur, fins, skin, and organs.
  • As indicated by feed-conversion ratios, it takes twenty-five pounds of feed to produce one pound of beef, nine pounds of feed to produce one pound of pork, and five pounds of feed to produce one pound of chicken.
    • Edible-food conversion ratios:
      • Chicken: 4.5 to 1
      • Pork: 9.4 to 1
      • Beef: 25.0 to 1
      • Carp: 2.3 to 1
      • Source
      • Extra
        • Calculating feed-conversion ratios is fraught with complexity. A good discussion of the difficulties of calculation and the various ways these calculations can be performed is on the A Well-Fed World website at awfw.org/feed-ratios/.
• There is no reason plants would experience pain.
  • Because pain is a response to avoid tissue damage by withdrawing or fleeing, and since plants have limited ability to withdraw or flee, there is no reason they would have evolved to feel pain.
  • Leonard da Vinci realized this. In one of his notebooks, he said, "Though nature has given sensibility to pain to such living organisms as have the power of movement—in order thereby to preserve the members which in this movement are liable to diminish and be destroyed—the living organisms which have no power of movement do not have to encounter opposing objects, and plants consequently do not need to have a sensibility to pain, and so it comes about that if you break them they do not feel anguish in their members as do the animals.”
• Some plants depend on being eaten for the survival of their species.
  • Some plants depend on being eaten to enhance the chances that their species will survive. The indigestible seeds of the plants will be spread over a wide geographical area as the plants are eaten by animals and then deposited in the animals' excrement.
• At a visceral level, you know plants and animals are different.
  • We all sense the difference between pulling up a dandelion and slitting the throat of a chicken.
  • Watching someone mow the lawn doesn't evoke the same reaction as watching someone kick a dog.
• Plants are sentient and intelligent only by the very broadest definitions.
  • Plants are sentient only in a way similar to how bacteria and other single-cell organisms are sentient or intelligent.
  • That is, plants generate and respond to chemical and electrical signals.