proves the validity of these ideas and feelings. Nothing is further from the truth... Just as there is a folie à deux there is a folie à millions. The fact that millions of people share the same vices does not make these vices virtues, the fact that they share so many errors does not make the errors to be truths, and the fact that millions of people share the same form of mental pathology does not make these people sane. Law In criminal and mental health law, sanity is a legal term denoting that an individual is of sound mind and therefore can bear legal responsibility for their actions. The official legal term is compos mentis. It is generally defined in terms of the absence of insanity (non compos mentis). It is not a medical term, although the opinions of medical experts are often important in making a legal decision as to whether someone is sane or insane. It is also not the same concept as mental illness. One can be acting under profound mental illness and yet be sane, and one can also be ruled insane without an underlying mental illness. Legal definitions of sanity have been little explored by science and medicine, as the concentration has been on illness. It remains entirely impossible to prove sanity. Furthermore, as Korzybski has pointed out repeatedly, insanity to various degrees is widespread in the general population, which includes many people that are considered mentally fit in medical and legal terms. In this connection, Erich Fromm referred to the "pathology of normalcy," while David Cooper proposed that normality was opposed to both madness and sanity. For a last will and testament to be valid, the testator must have testamentary capacity. This is often expressed using the phrase "being of sound mind and memory". See also George Eman Vaillant Insanity defense Rationalism Sanism Self-actualisation References Mental health law General semantics