Animal Consciousness - Summary of Conclusions Reached

In what follows, I review the major arguments for and against phenomenal consciousness in non-human animals, propose my own approach to the problem, review the behavioural data using my new approach, and briefly discuss the significance of animal consciousness in everyday human life.

The key points I wish to make in this section are as follows:

• No ontological conclusions should be drawn from the fact that we can logically conceive of animals possessing certain kinds of non-phenomenal consciousness without having any phenomenal experiences. The question of what kinds of consciousness animals possess has to be decided on empirical grounds.

• For a small circle of animals, the belief that they have phenomenally conscious feelings is a psychological "given" and can be described as properly basic, requiring no justification.

• Similarity arguments can be used to make a strong cumulative case that conscious feelings are widespread among mammals. However, these arguments cannot be applied to non-mammals, because of massive dissimilarities between the internal structure of the cerebral cortex of mammals and other animals. I present evidence that the cerebral cortex plays a crucial role in phenomenal consciousness.

• After carefully examining contrary arguments advanced by certain neurologists in support of the claim that conscious feelings may occur outside the cerebral cortex, I conclude that: (i) the evidence for feelings in mammals completely lacking both a cerebral cortex is doubtful; (ii) a case can be made for the existence of a primitive "affective" consciousness (centred in the anterior cingulate, which borders the cerebral cortex) that may have pre-dated the emergence of a "cognitive" consciousness in the cerebral cortex; (iii) there is no good evidence for conscious feelings in mammals completely lacking both a cerebral cortex and an anterior cingulate. In any case, since the anterior cingulate has a layered structure specific to mammals, it does not help the case for feelings in non-mammals.

• For vertebrates, we can identify structures in their brains that are homologous to those of mammals, because of their common ancestry. We may infer the presence of phenomenal consciousness in these animals if and only if the structures that are homologous to those that support consciousness in mammals also play an analogous causal role in regulating their behaviour. On this basis, I conclude that birds and possibly reptiles are neurologically suitable candidates for phenomenal consciousness, but fish and amphibians are not.

  For other animals whose brains are too unlike those of mammals to permit a comparison of their brains with ours, an inferential approach is required to ascertain whether they have conscious feelings: we need to identify behaviour on their part that cannot be plausibly explained except in terms of a first-person account.

• The fact that most of the behavioural phenomena commonly cited as evidence of conscious emotional states in animals can be explained using third-person terminology does not mean that animal feelings are not real. It means that we have to look for them in the right place, using appropriate criteria.

• I argue that while not all intentional behaviour by animals is conscious, the hedonic behaviour of animals often manifests conscious feelings. Recently researchers (Dawkins, 1994; Cabanac, 1999, 2003) have begun to identify ways of scientifically measuring conscious emotional states in animals, using insights from Utility Theory. We can also distinguish between rational and irrational desires in animals.

• Additionally, I suggest that a sentient animal's preoccupation with its own feelings creates affective distortions, which serve to identify conscious emotional states. These distortions can be measured scientifically, using insights from Risk Analysis and Decision Theory. I propose a test for identifying these states in animals.

• Although the absence of consciousness in an animal precludes our being friends with it, it turns out that the question of animal consciousness does not matter very much, from a moral or practical point of view. Conscious or not, animals have interests of their own, which can be harmed by our actions. Below, I discuss the welfare considerations for animals lacking consciousness.