A biologist, he was the chief zoologist on the ship Discovery during the British 1925-27 expedition to the Antarctic. The experience furthered his interest in marine biology, which led Hardy in 1938 to found the Oceanographic Laboratory in Edinburgh and the journal Bulletins of Marine Ecology and to write many books and articles. It was an article of his, “Was Man More Aquatic in the Past?” (New Scientist, March 17, 1960, 642-45), that led Elaine Morgan to write on the aquatic ape theory of evolution.
Hardy was a practicing Christian, who believed that religion and the doctrine of natural selection could be reconciled. In 1969 he founded the Religious Experience Research Unit at Oxford, and in 1975 he published a book The Biology of God: A Scientist’s Study of Man the Religious Animal. He claimed that a comprehensive biology of humankind should not ignore religious experience. The question he asked himself was: What is it in our makeup, in our biological system, that makes us need to seek out a religious experience continually? In trying to answer the question, he started with the emergence of early mental life in humans, of consciousness, and ultimately of esthetic, ethical, and spiritual awareness. He looked at many evolutionary theories including behavioral selection, at new discoveries in animal behavior, and also at developments in psychology and parasychology.