A mental event is a particular occurrence of something going on in the mind or mind substitute that make up the conscious mind of an individual. It can be a thought, a dream, a feeling, a realization, or any other mental activity. Some believe that mental events are not limited to human thought but can be associated with animal and artificial intelligence as well. The issue of whether mental events are identical with complex physical events, or whether such an identity even makes sense, is central to the mind-body problem.