1. The quality or state of being spiritual.
2. (Science: physiology) The doctrine, in opposition to the materialists, that all which exists is spirit, or soul that what is called the external world is either a succession of notions impressed on the mind by the Deity, as maintained by Berkeley, or else the mere educt of the mind itself, as taught by Fichte.
3. A belief that departed spirits hold intercourse with mortals by means of physical phenomena, as by rappng, or during abnormal mental states, as in trances, or the like, commonly manifested through a person of special susceptibility, called a medium; spiritism; the doctrines and practices of spiritualists. What is called spiritualism should, I think, be called a mental species of materialism. (R. H. Hutton)