This is more of a discussion on understanding predictions and readings, especially regarding the future.

Usually, the two terms are interchangeably used. When you go and have a reading with a psychic or channel (see here for the difference), you may ask a question and the psychic or channel will then pull the information from an interdimensional level where time and space do not exist as it is in our linear reality. We must understand that the future is not yet determined. The psychic or channel can only give you the potentials out of the infinite possibilities.

We have freewill and no psychic or channeled entity that respects your freewill will infringe it and tell you what to do. As such, given our freewill, we are making choices all the time. Multiply that by the decisions made by all the humans at any given moment and you can imagine how it is simply not possible to know exactly what will happen in the future.

Further reading

See the first question and answer at this Kryon webpage
http://www.kryon.com/inspiritmag/questions/Q%26Acurrentupdate.html