An experiment conducted by the British Psychological Society in 2005 suggests that under the controlled condition of the experiment, people who claimed to be professional mediums do not demonstrate the mediumistic ability. In the experiment, mediums were assigned to work the participants chosen to be "sitters." The mediums claimed to contact the deceased who were related to the sitters. The research gather the numbers of the statements made and have the sitters rate the accuracy of the statements. The readings that were considered to be somewhat accurate by the sitters were very generalized, and the ones that were considered inaccurate were the ones that were very specific.
If you've decided to hire the services of a medium, for whatever reasons, there are a few things you should keep in mind to guarantee you get the best session possible. First of all, try to come in with an open mind. You may be feeling skeptical, but if you let that be an issue, it can certainly color your results. A corollary to that is that it's important, to be honest about why you're there. If you're only trying to debunk things or to expose the medium as a fraud, go ahead and admit it up front. A medium who's legitimate will probably still be willing to work with you.
^ Leonard Zusne, Warren H. Jones. (1989). Anomalistic Psychology: A Study of Magical Thinking. Psychology Press. p. 221. ISBN 978-0-8058-0508-6 "The spirits, controls, and guides of a medium are the products of the medium's own psychological dynamics. On the one hand, they personify the medium's hidden impulses and wish life. On the other, they are also shaped by the expectations of the medium's sitters, the medium's experience, the cultural background, and the spirit of the times."
Everyone knows the great influence that is exerted by the voice of a friend who gives candid advice, assists by his counsel, corrects, encourages and leads one away from error. Blessed is the man who has found a true friend; he that has found him has found a treasure. We should, then, count pious books among our true friends. They solemnly remind us of our duties and of the prescriptions of legitimate discipline; they arouse the heavenly voices that were stifled in our souls; they rid our resolutions of listlessness; they disturb our deceitful complacency; they show the true nature of less worthy affections to which we have sought to close our eyes; they bring to light the many dangers which beset the path of the imprudent. They render all these services with such kindly discretion that they prove themselves to be not only our friends, but the very best of friends. They are always at hand, constantly beside us to assist us in the needs of our souls; their voice is never harsh, their advice is never self-seeking, their words are never timid or deceitful.
Theosophy is in opposition to the spiritualist interpretation of evolution. Theosophy teaches a metaphysical theory of evolution mixed with human devolution. Spiritualists do not accept the devolution of the theosophists. To theosophy humanity starts in a state of perfection (see Golden age) and falls into a process of progressive materialization (devolution), developing the mind and losing the spiritual consciousness. After the gathering of experience and growth through repeated reincarnations humanity will regain the original spiritual state, which is now one of self-conscious perfection. Theosophy and spiritualism were both very popular metaphysical schools of thought especially in the early 20th century and thus were always clashing in their different beliefs. Madame Blavatsky was critical of spiritualism; she distanced theosophy from spiritualism as far as she could and allied herself with eastern occultism.