James joined the American Society for Psychical Research at its founding, served as president of the British society in 1894 and 1895, and spent twenty five years investigating mediums, an activity his Harvard colleagues largely regarded as an embarrassment. His attitude was neither credulous nor dismissive, and he stated the logic of it in a line that has outlived most of the research: to upset the conclusion that all crows are black, there is no need to seek demonstration that no crow is black; it is enough if one crow is proved to be white.
His white crow was Leonora Piper, the Boston trance medium, whom he began studying in 1885. He never claimed she demonstrated survival of death, and he never found an explanation he was satisfied with either. What he concluded was narrower and more interesting: that in her trances she produced information he could not account for by any ordinary channel he had been able to test, and that the question therefore remained open.
He was equally clear about the state of the field as a whole. After a quarter of a century he wrote that he was baffled, that the evidence never quite closed and never quite collapsed, and that this baffling persistence was itself the most characteristic fact about the subject. The atlas holds the Victorian psychical researchers as a group, and James sits inside it, as the one member of it whose day job made his participation genuinely costly.