Dr. Herbert Silberer 
Problems of Mysticism and Its Symbolism [PDF ebook] 

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. We thus arrive at a science which may be called paleo-psychology. Its fossils are the thought-forms throughout the ages, and such a science seeks to show fundamental likenesses behind the more superficial dissimilarities.