The idea underlying many concepts of illness is that something has gone wrong with a biological system and some part of that system which has gone awry must be restored to it's proper function. The proper function of a biological systems is usually whatever allows that entity to live, breathe, exerts it muscles freely and vigorously without pain. When it comes to mental illness we extend that idea of proper functioning to anything that causes mental distress and is presumably due to biological problems with the brain. However there seems to me that something about that way of thinking is flawed because while it seems obvious when biological systems are disrupted rather than acting their natural course it does not seem obvious that mental distress is a product of biological aberrations. It seems rather like it is plausible that that is the normal course of life for humans even if that misery has a biological explanation.. So isn't mental illness essentially a flawed concept?