The idea of spirit contains several meanings. One definition of spirit points to an invisible incorporeal being, as compared to a ghost which allegedly is seen by a living person. But spirits, in this sense, can also been seen if they choose to manifest or if the seer is on the right wavelength, so to speak.
Spirit has several other meanings, such as an animating or vital force within life, the soul or some some kind of invisible force or presence that permeates the created universe (to include inanimate objects).
Spirit arguably becomes an ambiguous concept if viewed from a purely conceptual level. Many New Age thinkers, for instance, equate the notion of spirit with that of matter/energy. This is a dubious analog when we consider Rudolf Otto and C. G. Jung‘s treatment of the term numinosity and, moreover, the Christian understanding of The Holy Spirit. Otto, Jung and many mainstream Christians agree that there are different types of spirits, each with different types of numinosity.
It almost seems as if those who haven’t experienced any difference between their perception of matter/energy and spirit tend to automatically equate the two, just as one might equate any seemingly similar variables in the absence of any additional experiences that would complicate the picture.
By way of analogy, if one had never tasted white wine they might look at its color, recognize it as a liquid and claim that white wine is equivalent to apple juice or perhaps urine. And so it is, many mystics say, with the experience of spirit. Those who know (i.e. with gnosis), they claim, realize that spirit’s character may vary significantly, not only because spirit is passing through psychological and cultural filters, but also because of the differences inherent to the type of spirit in question.
Partly because mystics and seers have written about of so many different types of spiritual experiences, we also have the notion of “pure and impure,” “holy and unholy,” “good and evil” spirits, along with their respective tendencies to influence human beings for good or ill.
This tremendous diversity as to the meaning of spirit is not only found in Christianity but within most world religions. But, again, some well-meaning but arguably naive individuals simplify this diversity by making unsupportable claims, as did Sri Ramakrishna, who claimed that all spiritual paths lead to the same kind of spiritual experience. This may have been Ramakrishna’s belief when dabbling in different religions from his master perspective of Hinduism but it certainly isn’t everyone’s.