Yes, I vaguely remember reading books that were critical of the occult. A hundred years ago there were some very vocal critics of the occult who would explain in their books what was going on at séances or sayances and other such events. I have never seen one of those personally, but you can easily read about that and inform yourself. Oh, were you expecting a noisy barrage of opposition and criticisms? Would overcoming that energize your occultic batteries? What, you want to be the Wicked Witch of Babylon? Yes? Well, go right ahead, don't let me get in your way. Perhaps that explains why nobody wants to talk about that nowadays. I would not want you to get the impression that I care about that one way or another. Nowadays we have Youtube videos, Wikipedia and science to help fill in the knowledge blanks for us, so whatever. Be informed. Make your own decisions. The end times are coming.