Huxley's essay is about the use of the body in education. The amphibian in the title is a metaphor. Humans are like amphibians, according to Huxley, because they exist in several different contexts at the same time. For example, they are simultaneously ego-driven individuals and social animals that are part of a collective.

Huxley contends that language, while the defining characteristic of Homo sapiens, has given rise to another kind of split, which is between the mind and the body. Overreliance on language and thinking, in Huxley's view, privileges the verbal self; instead, he advocates a "non verbal" liberal education, one that would train the entire "psycho-physical instrument"—training in awareness of movement and musculature, the "special senses," memory, the autonomic nervous system, and spiritual insight.

Huxley argues that conventional education methods ignore the importance of the body in education and in fact introduce "bad habits" that prevent learning from happening. In order to learn, humans need to embrace their "amphibian" nature and enter into a state in which the ego is relaxed and the "vegetative soul" is active. In this way, the active problem-solving brain can be nourished by the unconscious intelligences of the body. For Huxley, this is also the gateway to a great spiritual awareness.