About Deaf-Blindness > What is Deaf-Blindness. Deaf-blindness is a low incidence disability and within this very small group of children there is great variability. Many children who are deaf-blind have some usable vision and/or hearing. The majority of children who are deaf-blind also have additional physical, medical and/or cognitive problems.
Introduction-David Hume. The Philosopher David Hume is famous for making us realize that until we know the Necessary Connection / cause of things then all human knowledge is uncertain, merely a habit of thinking based upon repeated observation (induction), and which depends upon the future being like the past.
MacLean expanded these ideas to include additional structures in a more dispersed limbic system, more on the lines of the system described above. MacLean developed the intriguing theory of the triune brain to explain its evolution and to try to reconcile rational human behavior with its more primal and violent side.