It is a mistake to suppose that a man must be a medium in order to attract to himself the beings of the invisible world. Space is peopled with spirits; they are always around us, always beside us; they see us and watch us; they mingle in our meetings, and follow or avoid us, according as we attract or repel them. The medianimic faculty has no influence in this respect; for that faculty is only a means of communication. After what we have said respecting the causes of sympathy and antipathy in spirits, it will be easily understood that we are surrounded by those who are in affinity with us, whether our state be one of elevation or of degradation.
-- Allan Kardec, from The Mediums' Book (point 223)