Questions about animal consciousness — in particular, which animals have consciousness and what (if anything) that consciousness might be like — are both scientific and philosophical. They are scientific because answering them will require gathering information using scientific techniques — no amount of arm-chair pondering, conceptual analysis, logic, a priori theory-building, transcendental inference or introspection will tell us whether a platypus, an iguana, or a squid (to take a few examples) enjoy a life of subjective experience — at some point we'll have to learn something about the animals. Just what sort(s) of science can bear on these questions is a live question, but at the least this will include investigations of the behavior and neurophysiology of a wide taxonomic range of animals, as well as the phylogenetic relationships among taxa. But these questions are deeply philosophical as well, with epistemological, metaphysical, and phenomenological dimensions. Progress will therefore ultimately require interdisciplinary work by philosophers willing to engage with the empirical details of animal biology, as well as scientists who are sensitive to the philosophical complexities of the issue.
What place should non-human animals have in an acceptable moral system? These animals exist on the borderline of our moral concepts; the result is that we sometimes find ourselves according them a strong moral status, while at other times denying them any kind of moral status at all. For example, public outrage is strong when knowledge of "puppy mills" is made available; the thought here is that dogs deserve much more consideration than the operators of such places give them. However, when it is pointed out that the conditions in a factory farm are as bad as, if not much worse than, the conditions in a puppy mill, the usual response is that those affected are “just animals” after all, and do not merit our concern. Philosophical thinking on the moral standing of animals is diverse and can be generally grouped into three general categories: Indirect theories, direct but unequal theories, and moral equality theories.
An entity has moral status if and only if it or its interests morally matter to some degree for the entity's own sake, such that it can be wronged. For instance, an animal may be said to have moral status if its suffering is at least somewhat morally bad, on account of this animal itself and regardless of the consequences for other beings, and acting unjustifiably against its interests is not only wrong, but wrongs the animal. Others owe it to the animal to avoid acting in this way. Some philosophers think of moral status as coming in degrees, reserving the notion of full moral status (FMS) for the highest degree of status.
Perhaps no aspect of mind is more familiar or more puzzling than consciousness and our conscious experience of self and world. The problem of consciousness is arguably the central issue in current theorizing about the mind. Despite the lack of any agreed upon theory of consciousness, there is a widespread, if less than universal, consensus that an adequate account of mind requires a clear understanding of it and its place in nature. We need to understand both what consciousness is and how it relates to other, nonconscious, aspects of reality.