Contact with "spirits" is in fact contact with the operator's own subconscious

Thomson Jay Hudson(1834 – 1903) born in Windham, Ohio, USA. He was Chief Examiner of the US Patent Office and a Psychical researcher, known for his three laws of psychic phenomena, which were first published in 1893.
Refusing his father's wish to become a minister of religion, Hudson funded his own study of law at college. He began a law practice in Port Huron, Michigan, but, in 1860, he began a journalistic career instead; and, in 1866, unsuccessfully ran for the US Senate. From 1877 till 1880 he was Washington Correspondent for the Scripps Syndicate[1]. In 1880 he accepted a position in the US Patent Office, and was promoted to Principal Examiner of a Scientific Division, a post he held until the publication of his remarkable book The Law of Psychic Phenomena in 1893.
He wrote and lectured on this subject until his death from heart failure in 1903.
Thomson Jay Hudson began observing hypnotism shows and noticed similarities between hypnosis subjects and the trances of Spiritualist mediums. His idea was that any contact with "spirits" was in fact contact with the medium's or the subject's own subconscious. Anything else could be explained by telepathy, which he defined as contact between two or more subconscious’s. (Mind reading.)
Hudson postulated that his theory could explain all forms of spiritualism, and had a period of popularity until the carnage of the First World War caused a fresh interest in spiritualism again as psychic mediums emerged to meet the demands of grieving relatives.
Hudson's three laws

1. Man has two minds: the objective mind (conscious) and the subjective mind (subconscious).
2. The subjective mind is constantly amenable to control by suggestion.
3. The subjective mind is incapable of inductive reasoning.

Hudson's books include:
The Law of Psychic Phenomena (1892)
• This book explores all areas of the metaphysical world from early philosophies to hypnotism and mesmerism, clairvoyance, visions, right through an overview of the psycho-therapeutic practices of that time.
A Scientific Demonstration of the Future Life (1895)
Law of Mental Medicine (1903)
Evolution of the Soul and Other Essays (1906)

Thomas Troward drew on Thomson Jay Hudson's The Law of Psychic Phenomena. Hudson believed in "objective" mind that works both inductively and deductively and in "subjective" mind that responds to objective mind only deductively. Troward converted Hudson's psychology into the theological belief that there is an impersonal, deductive, mechanical, automatic "Law" side of God. We feed thoughts, hopes, fears, etc. into the Law, and it responds by providing what we knowingly or unknowingly have ordered. This became a central part of Religious Science. Holmes's mystical tendencies and personal instruction from Emma Curtis Hopkins near the end of her career probably strengthened his beliefs.
Troward was on the leading edge of Psycho-Therapeutics which is now called as Mind-Body-Spirit.
Perhaps as Archdeacon Wilberforce believed, maybe reincarnation does perpetuate the belief of separation.

“. . .it will be seen that the so-called "ego" does not return to this material world, as it never has been in it, but always is in heaven.” ~ Life Understood From A Scientific And Religious Point Of View And The Practical Method Of Destroying Sin Disease And Death (1947) by F. L. Rawson

To Health, Happiness and Peace.

[1] The E. W. Scripps Company (NYSE: SSP) is an American media conglomerate founded by Edward W. Scripps on November 2, 1878. The company is headquartered inside the Scripps Center in Cincinnati, Ohio. Its corporate motto is

"Give light and the people will find their own way."