Adult humans know they exist, commonly referred to as self-awareness, self-consciousness, or sentience. This is one of the highest expressions of humanity, and could only come from a soul. As the source of thoughts and beliefs, the soul expresses the essential traits of being human, namely, we think, we make decisions about important life issues, we form beliefs, and we know we exist, all in our immaterial inner human. These are not brain functions since the material cannot achieve such heights of humanity. But because humans have a soul, we can think high level thoughts and have beliefs in that soul, centered on knowing these things matter to self, to others, and to God.
But to conjecture within the absurd for a moment, even if somehow a brain could have such advanced humanity thoughts and beliefs, it would not matter since at death it would all be gone. Forever. Nothing remaining. Without the soul, nothing about our existence would matter since it would only be very temporary. What use would that be? God certainly would not be part of such an absurdity, which is why He gave us a soul which will live forever. Therefore our life matters. The soul gives life meaning and purpose.
Humans are required by God to use our soul to make decisions and choices, ultimately for or against Him. That is why we exist. And only a self-aware being can ask why they exist. As an added bonus you just learned the answer to the ultimate question of life, "Why are we here?" which is answered only by the Bible. We are here to make decisions for or against God. And the choices we make determine future outcomes, both during our lifetime and forever. One of those decisions might be about what we eat for lunch, and another about our relationship with God. One has eternal implications, and the other does not. But life is about thoughts and beliefs leading to decisions related to God. And those decisions are not from a brain in the body. The brain is not the fount of human existence. The brain is sensory and temporal. The soul is humanity and forever. Regarding why beliefs are important, they are what drive and motivate people. All beliefs are formed in the inner human, and belief is what God requires of humans if they are to have eternal salvation. That alone makes beliefs the most important issue in life, because it determines our eternal status. By comparison nothing else comes close in importance.
But how do humans develop the ability to think and form beliefs? And how do we become self-aware?
Newborns do not enter the world with thoughts, beliefs or self-awareness. The soul is blank at birth, so these must be developed over time. The first thing a human baby does is to begin taking in sensory data, which is an empirical process of learning about the outside world through the five senses as we have previously described. The newborn's soul must learn and recognize that there is such a thing as the world outside of itself, then learn about it and how it operates. It is a fire-hosing process at first with no frame of reference or memories to relate anything to. Over time repetitive patterns occur which begin to make sense. Those which the newborn will later recognize as "people" show up regularly and then the baby eats, which satisfies a basic need. Things which lead to eating and comfort become associated with goodness. Massive amounts of sensory data is experienced. Language is heard repetitively. Eventually this sensory data is cataloged in memory and becomes recognizable as patterns. Basic thoughts begin to be formed in the soul, usually about food, discomfort, and other needs. Over time as vocabulary is developed, rapid progression of learning occurs. And on it goes as the soul is developed into something which can think, and eventually form beliefs about the world around it. Much later self-awareness begins, once the growing child understands that the outside world and self are different but connected, and that one's own actions affect what the outside world can do for self. So we see that newborn babies are truly human, but do not think until they first accumulate sufficient empirical sensory inputs into their soul, which eventually enables thinking, and later beliefs and self-awareness.
Therefore the human soul develops first by taking in empirical sensory data as the senses identify the sights, sounds, smells, tastes and touch sensations we encounter, categorize them, and try to match them with sensory memories in the brain. The soul develops mainly through this sensory-based learning process, which is the primary means of understanding the world around us. We have previously described this learning process as a shared brain-soul endeavor whereby the brain supports the needs of the soul. Then at some point there is enough accumulated information to form thoughts, then the person begins learning by teaching from others (a faith-based process), and eventually thoughts form beliefs, then beliefs serve as a prism for developing future thoughts and higher level beliefs. At first memories are mainly sensory, but eventually thoughts and beliefs develop life memories. And we know it was us who experienced all those things, not someone else, so we know we exist. We are self-aware. That is truly human.
Speaking of knowing we exist, Rene Descartes, the father of modern Rationalism, said his philosophy started with the premise "I think, therefore I exist" as the most basic of human rational thoughts. Sorry, but that is backward. Descartes was trying to ignore his lifetime of empirical sensory learning so he could use only deductive reasoning (rational thought) to know anything with certainty. However, his own thinking and self-awareness were based on that empirical learning, which he tried to ignore, but failed. That is because humans are not born thinking, even though they exist, so the concept "I think, therefore I exist" works only after many years of empirical sensory learning. Newborns exist, but do not think. The ability to think must be learned, because at birth the soul is blank and empty, and therefore cannot have thoughts or be self-aware. Empirical sensory information must be taken into the soul first by the five senses, then through the brain, and then into the soul where the foundation for thinking is formed over time. Eventually this leads to thoughts, thinking, beliefs, and self-awareness. All of this makes empiricism, which Descartes was trying to avoid, the foundational basis of rationalism and deductive reasoning. We use this example to show how someone who is so revered as a great Philosopher for striving to explain how he could know anything with certainty came up with a conclusion which is fundamentally flawed. Descartes is just another example of how far short science and philosophy fall when trying to come to conclusions about human thought and beliefs when the Bible is ignored.
There is also a difference between the immaterial parts of believers and unbelievers. This involves the human spirit, which is separate and distinct from the soul. We define "believers" as those who have believed in Jesus Christ as their Savior, and we define "unbelievers" as those who have never believed in Jesus Christ as their Savior. The Bible says our beliefs separate us into two groups and determine our eternal futures. It declares "Believe in the Lord Jesus Christ and you will be saved" and "For by grace are you saved through faith." That one specific belief separates those who are on the side of God from those who are not. There are believers and there are unbelievers, a clear separation among humans. With those definitions outlined, we can proceed to understand the inner workings of the human soul, and we will also come to understand how the human spirit is different than the human soul, but function together and in tandem, although one group of humans (unbelievers) only have the soul but not the human spirit. We will see how this important difference explains many things about the functions of the inner human.
The immaterial part of humans is amazing. The Bible says "We are fearfully and wonderfully made." But humans are also capable of the most heinous thought distortions imaginable. One of the basic questions people ask about this subject area concerns how different people can look at the same set of facts and come to polar opposite conclusions. This can be related to many things in life, such as politics, morals, religion, economics, environmental issues, business, the origins of the universe, diet and exercise, relationships, and so on. This is where beliefs come into play. Beliefs are often strongly held and will determine what conclusions will be drawn. Beliefs are powerful influencers which are not easily changed, because they are at the core of what a person thinks about themselves, and therefore who they really are. If you ask a person to tell you who they are, they will ultimately describe their beliefs. Humans can be incredibly logical and at the same time hold outrageously illogical thoughts and beliefs in certain specific areas of life. And yet they are not considered to be mentally unstable, or to suffer from a diagnosable mental illness. They may appear to think abnormally to you, but they are not abnormal in a medical sense. And they may think you are abnormal. It all seems unexplainable. But the Bible makes sense of all of it, and these issues will be explained as we proceed. Many of the answers will likely be surprising. Maybe even shocking.
Science, philosophy, and medicine cannot explain what constitutes a true human, which is the soul. They cannot explain its component parts, where the soul resides, how it functions, what causes distortions of thinking in the soul, or a host of other important issues related to true humanity. Most do not even believe there is such a thing as a soul. And when someone starts with the erroneous premise that the brain is the source of humanity, that the soul does not exist, and that humans are just sophisticated animals, their conclusions inevitably fall far short, and most are downright foolish.
So we can begin to see the difference between the brain and the soul as related to thoughts and beliefs. The brain is an artificial intelligence sensory interface and gateway which connects the five senses to the soul, and stores basic data such as learned repetitive actions. It supports the soul, which is the center for high level thoughts and beliefs. The brain sends information into the soul, and then accepts instructions back out from the soul. The brain gathers sensory data, enables repetitive motions, allows us to quickly avoid hazards, relieves the soul of an enormous workload, and provides the soul with information about the world around us. The brain is the interface between the outside world and the soul, but the soul is the center of being human. It is the ultimate destination of the sensory information fed into the brain, which in turn is manipulated by the soul whereby we make decisions and figure out where we are headed with our life, and also remember where we have been. The soul is where we store high level memories, where we think, and where we love and feel and have deep-seated beliefs. It is where we have self-awareness, knowing we exist as a unique individual. The soul is where we live as humans. The brain is material and programmable. The soul is the immaterial real person and the center of our humanity.
That brings us to the point where we can now discuss the design of the human soul, its components, and how it works.