tokens: Originally , the term was created to distinguish physical ( termed " organic " ) causes of mental impairment from psychiatric ( termed " functional " ) disorders , but during the era when this distinction was drawn , not enough was known about brain science ( including neuroscience , cognitive science , neuropsychology , and mind-brain correlation ) for this cause-based classification to be more than educated guesswork labeled with misplaced certainty , which is why it has been deemphasized in current medicine .