I just started reading Euan Macphail’s book The Evolution of Consciousness and the first chapter raises an interesting question: do animals have consciousness?
First, we need to define consciousness in order to determine whether or not animals besides humans possess it. We could roughly distinguish between two types: feeling-consciousness and metaconsciousness. Metaconsciousness is often referred to as self-consciousness and seems to depend on there being a self-concept in place that allows for such metacognitive functions as knowing that you know, thinking that you think, desiring about your desires, etc. Metaconsciousness seems to be a very rare cognitive skill and could plausibly be restricted to humans only since it seems unlikely that a mouse knows that he knows something, or is aware of his own awareness. Moreover, we must be clear to distinguish metaconsciousness from prereflective bodily self-consciousness, which is the self-consciousness that arises from simply having an embodied perspective on the world and not necessarily from having an explicit self-concept structured by linguistic categories such as self, person, soul, mind, consciousness, etc. Although all animals could be said to have bodily self-consciousness, it is unlikely that nonhuman animals have a self-consciousness of this bodily self-consciousness.
In contrast to metaconsciousness, we can talk about what Macphail calls feeling-consciousness. Obvious examples of feeling-consciousness include the experience of pleasure, suffering, love, motivation, etc. Moreover, feeling-consciousness includes sensory feels such as my the feeling that I am currently looking at my laptop screen, or the feeling of my clothes on my body and the keyboard against my fingertips.
While many people would agree that nonhuman animals do not have metaconsciousness, it seems plainly wrong to deny animals feeling-consciousness. After all, isn’t it quite clear that an animal experiences pain in the same way humans do? This argument is often made through analogous comparisons of behavior. We assume that if a person pricks a human with a needle, and the human rapidly withdraws his hand, he does this because the needle hurts. And since we can prick the paw of an animal and the animal exhibits the same rapid withdraw, then we would be perfectly right in concluding that the animal also withdraws because it feels pain. The same goes with vocalization. If you prick a human with the needle, he might yelp or cry out in pain. And if we prick an animal, it will also make a vocalization in response. We can also measure involuntary responses like heart rate. When a human experiences pain, these involuntary processes occur. And when we prick an animal, we see the same involuntary responses. The obvious conclusion then is that animals feel pain just the same as humans.
But are these behavioral criteria necessary for feeling pain? We wouldn’t, for example, think that vocalization is necessary for the experience of pain, since a human born without vocal cords would surely experience pain just the same. Same goes for the withdrawal response. If you sever the spinal cord of a dog from its brain, the dog will still exhibit a withdrawal response. Same with humans. Humans with a severed spinal cord still exhibit withdrawal reflexes despite not feeling anything so the mere behavior of withdrawing a limb should not necessarily indicate the existence of feeling. After all, if we programmed a robot to rapidly withdraw its arm when exposed to a sharp force, we wouldn’t conclude that it feels anything simply because it shows the appropriate behavioral response. As Macphail puts it, “An actor could reproduce all these symptoms without feeling any pain at all, and that, in essence, is why none of these criteria is entirely convincing.”
Moreover, we could go beyond analogy and argue that of course animals feel pain since pain is highly advantageous from an evolutionary perspective. If an animal didnt have the appropriate mechanisms for feeling pain, then it would have not been nearly as successful as the creature who did experience pain. From this perspective, the function of pain is quite clear: to motivate us to avoid dangerous things.
But Macphail asks us to consider an armchair scenario about the evolution of pain. It is widely supposed that life began from the self-assembly of chemical building blocks enclosed within a semipermeable membrane. These first organisms were basically complex chemical machines, and most people would agree that we can account for everything in terms of biochemical mechanisms. To explain the behavior of the organisms, we wouldn’t suppose that they have feeling-consciousness since, presumably, such chemical machines wouldn’t feel anything. Now, suppose that as multicellular organisms evolved there arose a cellular specialization wherein cells became nerve cells, sensory cells, and motor cells. The sensory cells function to detect information in the environment, which then act to encourage nerve cells to activate, which then encourage motor cells to activate.
The coordination of these different cells gives rise to to ability to react to dangerous stimuli. If the chemical machine wanders into a toxic area of the ocean, then the sensory cells can detect the significance of this stimuli and relay the information to the nerve cells, which then activate the motor cells which allows for the organism to escape from the dangerous stimulus. As Macphail says, “The point is, that it is easy to envisage the rapid early evolution of links between sensory systems and motor systems that would result in withdrawal from disadvantageous areas and of similar systems for approach to advantageous areas. It is equally easy to see that this scenario has proceeded without any appeal to notions of pain or pleasure.”
The question then is this: where does feeling-consciousness fit into this story? What is the function of feeling pain/pleasure that could not be accounted for in terms of the biochemical mechanisms and their increasing complexity? Why would an early organism need to feel pain when the mechanisms for avoiding dangerous stimuli and approaching advantageous stimuli are sufficient for the task of survival? Feelings don’t seem necessary for the adaptive success of an organism, a point which raises some very interesting philosophical questions.
With all that said, I need to make some qualifications. Although the above considerations lead us to believe that feeling-consciousness is not necessary for the adaptive success of animals, there is another sense of consciousness used by philosophers that does seem applicable to these lower organisms: phenomenal consciousness. Phenomenal consciousness is usually defined in terms of the “what-it-is-like” to exist. Presumably there is “something-it-is-like” to be a bat. This something-it-is-like is often talked about in terms of raw feels, such as the raw feeling that there is something-it-is-like to taste an apple or enjoy the blue sky. On my view, there is also something-it-is-like to be a bacterium, although it is very dull in comparison to the what-it-is-like of more complex organisms. However, I also want to claim that the raw feels which constitute the what-it-is-like of an organsim are not the same as the feeling-consciousness discussed above. Although many philosophers would disagree with me about this, I think that it is precisely the ubiquity of feeling-consciousness in humans that makes us think that the same feelings must be present in other animals. When humans gaze up at the blue sky and enjoy the feeling of pure sensory quality, I want to claim that this experience is unique to humans, for although a nonhuman animal is capable of perceiving or detecting the blue sky, it is probably not capable of feeling that it is perceiving, or feeling that it is detecting. To consciously feel sensory experiences requires that one “feel” how one perceives the world, as opposed to just perceiving the world. I claim that the perception of the world and the feeling that one is perceiving the world are two radically different phenomena, with the latter perhaps depending on the linguistic, self-reflexive cognition of human minds. Philosophers rarely recognize the significance of this distinction, and their philosophy of mind suffers accordingly.
Lastly, I want to briefly discuss the ethical implications of the seemingly radical position that animals don’t have feelings. Some people would think that even if this idea is true, it leads to such horrible ethical consequences that we should never even entertain it as a hypothesis. But I disagree. I think the idea that animals don’t consciously feel anything and the idea of animal rights are not mutually exclusive. One can hold the position that animals don’t feel pain, while still believing that we should be humane in our treatment of animals and that we shouldn’t cause animals any unnecessary discomfort. One could believe that animals don’t feel pain but merely detect dangerous stimuli while still believing that we should work to decrease the amount of dangerous stimuli detected by animals. In this way the idea of an animal ethics is perfectly compatible with the views I am entertaining here.