Since its foundation in 1882, the Society for Psychical Research (SPR)—the first large organisation to scientifically investigate controversial phenomena associated with mesmerism and spiritualism—has boasted a considerable number of notable physical scientists among its members. They included, for example, the discoverer of thallium and president of the Royal Society, William Crookes, the pioneer in wireless telegraphy, president of the Physical Society and first principal of Birmingham University, Oliver Lodge, as well as Nobel Laureates such as J. J. Thomson, Marie Curie, Lord Rayleigh (John William Strutt), and, more recently, Brian Josephson.
International in character, the early SPR also counted a noted German physicist among its members: Heinrich Hertz, after whom the international unit of frequency in physics (hertz, Hz) was named. The first to broadcast and receive radio waves, Hertz became acquainted with Oliver Lodge through their mutual interests in wireless transmission technologies. In his obituary of Hertz, Lodge wrote in the Journal of the SPR in 1894:
During a visit to England in 1890 to receive a medal from the Royal Society, he betrayed an interest in psychical matters, and related to the writer some experiences which had convinced him that there was matter for investigation in these ‘occult’ regions.
Lodge proposed Hertz as a Corresponding Member of the SPR in April 1891. Hertz accepted, but died less than three years later.
Another acquaintance of Lodge’s, Max Planck (the Nobel Laureate commonly referred to as the founder of quantum physics), never joined the SPR but expressed sympathies for Lodge’s unorthodox investigations in telepathy and mediumship. I found a letter from Planck to Lodge in the SPR archives at Cambridge University Library (SPR.MS35/1752), which I translate with the kind permission of the Society. Confirming receipt of Phantom Walls, Lodge’s latest opus on spiritualism, Planck wrote on 19 December 1929:
You gave me great joy by kindly sending me your book “Phantom Walls”, and I hardly need to assert that I will gratefully keep this valuable gift in honour. Not only will it be a cherished souvenir of that eventful and interesting day which I got to spend in London two weeks ago, but by reading it I also promise myself many a new valuable stimulation in addition to the plenty which I have previously received from your writings. – The thing that for me has always made the standpoint represented by you plausible and likeable is your unshakeable faith in the existence of a real outer world independent of us, in which we humans play only a relatively humble and minor role, and your rejection of the positivist viewpoint, which seeks to do away with all questions associated with this real outer world by declaring them meaningless. Rather, we must be content that much will remain mysterious to us, no matter how much we advance in knowledge. But we always have the consolation that we steadily approach the truth, even if we can never fully attain it.