The evolutionary origin of consciousness has been a growing area of study in recent years. Nevertheless, there is intense debate on whether the existence of phenomenal consciousness without the cerebral cortex is possible. The corticocentrists have an empirical advantage because we are quasi-confident that we humans are conscious and have the well-developed cortex as the site of our consciousness. However, their prejudice can be an anthropic bias similar to the anthropocentric prejudice in pre-Darwinian natural history. In this paper, I propose (...) three basic principles to provide a conceptual basis for evolutionary studies of consciousness: the non-solipsistic principle, the evolution principle, and the anthropic principle. These principles collectively help us to avoid solipsism, anthropocentrism, and anthropomorphism to some degree, although we cannot be completely free from them. Also, the landscape metaphor associated with the anthropic principle provides an image of how different forms of consciousness can be acquired. (shrink)