A simplistic mind is a mind full of answers. It is also a mind that seldom realizes the simple fact that answers must be preceded by pertinent questions. The person with a simplistic mind looks for inspiration and knowledge in simplistic theories, mainly in those that confirm his or her preconceptions. Furthermore, he or she tends to be very active. Hence, we are talking about someone who can be very dangerous indeed.
There never was a sounder logical maxim of scientific procedure than Ockham's razor: Entia non sunt multiplicanda praeter necessitatem. That is to say; before you try a complicated hypothesis, you should make quite sure that no simplification of it will explain the facts equally well.