Primary function of the nervous system
The essential aim of the nervous system is to keep a living organism alive (1). Why? So we may achieve at least one fundamental goal in life - that is, to successfully reproduce a new living organism - although there are many other goals a human being may set before him/her throughout life as well. From a purely biological point-of-view, it is to reproduce. Beyond that, any other goals we reach for is determined by the dreams we create in our brain and the decisions we make for ourselves on which dream(s) should become a reality for others to enjoy.
To keep itself alive, the nervous system has to operate along the same principle as in engineering physics: the negative feedback system.
The negative feedback system - how does it work?
The negative feedback system works by gathering sensory information about the environment; processing the sensory information to create or uncover patterns; and responding to the processed information (or patterns) by changing behaviour. It then repeats the process, sensing continuously what changes occurred in the environment as a result of a recent change in behaviour, until equilibrium is reached whereby the needs (or goals) of the organism are satisfied.
It does all this because, in the words of Rene Magritte: 'The mind does not understand its own reason for being.' (2)
Behaviour and understanding: the brain's obsession throughout its working life
Neuroscientist and Nobel Laureate Dr Roger Wolcott Sperry, an American professor of psychobiology at the California Institute of Technology, USA, explains the contribution of the brain to the whole organism:
'The brain's primary function is essentially the transforming of sensory patterns into patterns of motor coordination [and other behaviours]....In man, as in the salamander, the primary business of the brain continues to be the governing, directly or indirectly, of overt behaviour.' (3)
Behaviour is defined here to mean everything that we do, including physiological responses as well as purposeful actions and thinking. Physiological responses include the activation of biochemical reactions. In The Molecular Biology of the Gene, a definitive textbook, we read that:
'...the inescapable conclusion is that we human beings, proud possessors of sophisticated intelligence, will find that our behaviour is governed to some extent by elementary biochemical reactions.' (4)
Whatever we do, say or think, no matter what the reason might be, it is all driven by the fact that we want to survive (ie. be happy) and understand so we may achieve certain goals in life. And for the brain (and body) to survive and achieve those goals, it has to learn to understand itself and its environment and to create appropriate behaviours in the human body to see how they will affect itself and the environment in the achievement of those goals and so make any adjustments where necessary. As Hugh Gilmore in Philadelphia Inquirer Magazine once wrote:
'The human mind is as driven to understand as the body is driven to survive.'
