Realities are a complex, evolving attribute of the human species, as well as a necessary part of the individual mind.
Truth is an absolute certainty.
Humans have only versions of truth, or realities, which are used as substitutes. Each reality is thought to be the Truth by its advocates, but all human realities can be seen as changing over time and varying from culture to culture. Truth cannot change. Realities change to keep up with changing situations and data. We are, in effect, clueless about the true nature of our existence, so we must create our own reality.