There is very little scientific proof that there are spirits.
Anthropologists have found that the unseen realm of spirit has been very much a part of human society and culture going back to the Ancient Egyptian cultures, back in the history of mankind, beyond Mesopotamian Religions to the days of the Ramayana, 20,000 years ago. Each and every society has its ways of the spirit, of accessing the spirit realms through prayer and sacrifice worship and ritual.
If you look at man, is it said that is a union of mind, body and spirit. The international distress signal is S.O.S. which means Save Our Souls, which infers that there is a spirit within the human person.
The English word "spirit" has many differing meanings and connotations, but commonly refers to a supernatural being or essence — transcendent and therefore metaphysical in its nature: the Concise Oxford Dictionary defines it as "the non-physical part of a person". For many people, however, spirit, like soul, forms a natural part of a being: such people may identify spirit with mind, or with consciousness, or with the brain.