Abstract
A phenomenal concept is a concept that one possesses only if one has the relevant experience. In this essay, I argue that phenomenal concept theorists, namely, those who believe that we acquire phenomenal concepts through being acquainted with the relevant experience, can never succeed in determining which species of non-human animals are phenomenally conscious because they prohibit any a priori correlation between phenomenal and non-phenomenal concepts. I make my argument by first discussing several ways in which a phenomenal concept theorist may explain which animal species are conscious, namely, with neuro-identity theory, behaviorism, and functionalism, and the problem that these approaches entail. I then illustrate how the alternative approaches of scientific inference to the best explanation, analogical inference, similarity inference, and inference by prototype face the same problem.