There are a great many books and teachings that have a lot to say regarding this topic. I am a well read person, but after a little bit of reading some of these books my head begins to swim and I have lost where the author was leading me to believe, and living in the counter-argument that was forming in my head. Simplistically, (I think this is a science thing too) there is likely multiple levels of existence. Some call them planes. What I am in here and now is the human physical and conscious plane (human plane). Any being not on this plane can be considered in an enlightened plane, or somewhere else all together. Where are the dead? I have no idea. The spirits of the dead appear to have many options, depending on their chosen belief system. Reincarnating religions such as Buddhists, Hindu, and Krishna believe their spirits are reborn in a new baby, come back to earth to re-live life, either on a higher or lower part of the totem pole, until they have become the best possible person they can ever achieve. Standards of what that is is not published, and a little fuzzy. If you are of the Abrahamic faith (Christian, Jewish, and Isliamic) then you get one shot at being in the human plane, and then you move on to another plane of existence, your moral and ethical practices on the human plane being the determining factor in where you go. Follow a set of rules that was provided by a being from a different plane of existence, go to happy plane of existence; failure to do so finds you sent to a horrific plane of existence. A mulligan is provided upon request, in unlimited number (sincerity not required). Some Pagans believe that they are of the reincarnation group, and others believe they are of the being sent to a happy plane of existence group without the bothersome rules. Now whether or not any of that happens, only the dead know (hah! I crack myself up!).
Now there are some who believe the spirits that are in regular contact with the human plane have not been sorted into their plane of existence, or chose to stick around for their own reasons. Some Pagans have the capability to contact spirits and communicate with them. Their abilities allow them to do some, but not all, of the following: sense the spirit, determine gender, hear or sense a message, determine the relationship the spirit has to the person being read. How a reader does this can be various, and can stretch the limits of common sense and imagination.
However, if you are greatly influenced by conservative Christian groups, this can be viewed as a gateway to evil. Many times I encounter Christians who really like me, and are terribly afraid that I will be taken over by an evil demon, and that the things I know and do come from a great source of evil and I should stop.
Let’s explore Good and Evil, or, Positive and Negative. Pagans do not believe in the Christian concept of an ultimate negative being that has the capability to directly influence those on the human plane of existence in a manner that would cause harm and chaos to the rest. They do believe in energies that can be positive or negative. It is rare to find a Pagan that believes these energies can manifest themselves in a little more physical form to directly conducts acts of good or bad. Some Pagans use cultural appropriation from the Buddhists and Hindus and use the concept of Karmic balance. One external act of positive or negative causes the same in kind on you, in equal proportions. A majority of Wiccans believe that if a Wiccan does it, then it comes back on them-triplicate. Some Pagans have the ability to determine if an object, location, or person is exerting positive or negative energy. Some Pagans believe they can concentrate the negative energy into specific objects (called charging), then burn them to release the negativity out into the universe away from them and others. Some believe they can use their own positivity to concentrate positive energy into objects for long term, slow release of positive energy for the owner of the object.
It can be difficult to determine the credibility of any Pagan you happen upon who lets you know there is a spirit connected to you that is hanging out wanting to chat. If you happen to be in a space and place that it is expected that you get a message like that, say-oh- a psychic fair, then this shouldn’t be a great surprise and a cause of too much stress and pain. Whatever the circumstances, the following advice will always be the same. A person will tell you what they are being paid to tell you. I hardly believe that if you pay a psychic to tell you if you are haunted that they would tell you nope, you are terribly mistaken! I also would say that the state of mind you are in determines how vulnerable you are to suggestion. Being in an unfamiliar place, that can be slightly uncomfortable and creepy, that has you uptight and stressed out is a perfect moment to be told that the spirit of a long (or recently) dead relative is hanging out eating a snickers waiting for you to listen. When you chose to believe this, then you take on the extra stress of feeling attacked and targeted. Those with a vulnerable personality will likely either: request that the spirit is banished- and that will only cost you upwards of going into debt forever; or begin going into a psychiatric spiral of fear and depression. Keep yourself together people! Unless you have had your senses tingling without being prompted that something or someone was there, and you could sense who, then keep your head, and make your own common sense determination as to the credibility of the information being provided by any outside source.
So what are spirits likely to communicate. A lot of things. They are asked to weigh in on divination readings, or provide a message of love and comfort to the intended receiver to boost their spirits, or that they are too bored with the other planes of existence options, and just want to kick it with the rest of us.
What ever the relationship with a spirit, it will only go as far as you want to take it. Some Pagans believe you can banish a spirit and set up protective energies to ward any off, if you chose. The best time to communicate with a spirit? Samhain, more locally known as Halloween. Some Pagans believe that two planes of existence (human and spirit) are separated by something they can only describe as a veil. This separation, or separating (thing?) either gets weaker, thinner, or translucent, and provides optimal conditions to easily communicating with those on the spirit plane, whether they had made an appearance on the human plane, or not.
I am sure I am missing a whole host of other things I can say on the topic of spirits, but I am drawing a blank.