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. However, it isn't the only goal to achieve in life. In reality, we all know that there has to be other goals a human being must set, pursue, and achieve in his/her lifetime. Obviously, in the short-term, fundamental goals such as finding food will be essential to our survival. In the long-term, hopefully all human beings will eventually want to achieve the ultimate goals of who we are, what our purpose is in the Universe, and where we are heading given the way the Universe beckons us to find out more and discover new insights we have never seen before. At any rate, it is true that from a purely biological point-of-view, it is to reproduce. Beyond that, any other goals we reach for is determined by the dreams and aspirations we create in our brain and the decisions we make for ourselves on those things we wish to see become a reality for the benefit of everyone.
To keep itself alive and see to it that such goals are achieved as best we can, 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 life-long obsession
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. Purposeful actions include a wide variety of motor control activities such as raising an arm to say, "Hi!" and/or to show a smile on our face. 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, because of its connection to the mind and body, the brain and the rest of the nervous system are all driven by the one solitary fact that they want to survive. To do the best it can in achieving this goal, the brain must understand itself and the environment and ultimately answer the meaning and purpose of our existence in this universe so we may be happy and peacefully be as one in the universe for all times. That is the ultimate goal. Because, with that knowledge, it should be possible to find a way to survive indefinitely. No living cell or organism wants to die. Everything wants to pursue the goal of staying alive. It is natural. The human brain and nervous system is there to understand how and why and to find those patterns. The rest is up to us to support the patterns the brain uncovers and decide how best to ensure our survival is maintained for as long as possible.
For the brain (and body) to learn and understand all the vitally important patterns needed to stay alive long enough to achieve at least a certain biological goal, it has to achieve other short-term goals in life such as finding food, problem-solving, and displaying certain behaviours 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."
As a newborn for any animal species, the aim is to find food, warmth, security and other forms of love to help satisfy the brain and body's immediate needs for survival. Unfortunately for a number of humans in third world countries, rarely do they get the opportunity to get beyond meeting these survival needs because of the state of the world where food is limited, people are greedy and want to control and sell the remaining resources, and conflict is prevalent as people seek solutions to their survival predicament and look for scapegoats in others as a result.
As children reach the age of 3 to 7 years, they begin to ask themselves "Who am I?" as they do a lot of exploring, asking questions and reacting to their environment such as touching a tiny thorn on a bush or feeling the ocean water rush up to and surrounding their feet as well as parents telling them what not to do and hopefully receive regular encouragement for the things they do right or shows initiative and self-thinking to make them feel happy.
As humans reach adulthood, they question their own uniqueness by looking at society and whether they are a valuable member of society. Teenagers seeking to understand their place in society and so refine their own identity will achieve this through their experiences, the knowledge they receive and the relationships they develop with other teens and sometimes older adults they may look up to or gather other experiences and knowledge.
When humans become adults, certain social responsibilities are taken onboard as they realise their duty to help individuals in society to achieve certain goals and in return receive the reward they need to survive and perhaps achieve their own goals (and depending on their upbringing and how they were treated, we hope the goals will benefit society). In developed nations, most people never do more than find a job and help a few people. Generally the cost of living and purchasing a roof over one's head is so exorbitant that in most cases people decide there is usually nothing much else to do in life but continue working for others to receive an income where they can pay off the mortgage bit-by-bit over time, have a family, and then hopefully look forward to a comfortable retirement.
When humans are much older and hopefully have fulfilled their full potential through the goals they wish to achieve for themselves (which usually might be to own a house, have kids and live comfortably) and not necessarily doing what others want them to do all the time, they become more themselves as they realise their own true uniqueness and special identity. And yet they feel no different from anyone else. It is okay to be different and yet we are the same. They no longer have to be like others and try to be pretty or look cool as they may have had to do when they were teenagers. In order to achieve great things in life it is not necessary to look good, just be yourself.
It is at this moment when humans have self-actualised and become fully independent and capable of thinking for themselves without worrying about what others think, and be genuinely happy. But we can only hope at this stage in human development that the thirst for knowledge and finding solutions to problems will not end.
And when humans do stop questioning life and the universe because they feel there is nothing more to understand or learn about and are at ease, the brain will stop dreaming and soon we will die. So long as the body is healthy, the brain needs to be active, seeking to find answers to questions, and dreaming of new ways of doings things or seeing a solution for humans to live a very long life.