To understand the consciousness, we need to understand it in many different ways.
From the perspective of our human body, consciousness is "the feeling of thinking", there is no mystery.
When our body is doing something, like making a fist, the nerve cells in our body produce feelings. Thinking is like the brain doing some "actions", and the feeling we feel is consciousness. The reason why consciousness is difficult to understand is because the body's senses are separate from the brain's thinking, and we can easily identify these sensations, but consciousness is the brain's senses of its own activities.
We can also start from the sense of the body, and gradually upgrade our senses to understand the consciousness: suppose we close our eyes, and when we reach out to touch an object, simple tactile sensations occur; if the object is cold or hot, we may feel pain and fear, which are more complex senses; if the object has a specific texture or shape, we may begin to generate consciousness related to this object. In this process of consciousness escalation, the complexity of the brain's consciousness increases gradually, but there is no essential difference between these "senses" or "feelings". The resulting complex consciousness, just like the dominoes, triggers a lot of follow-up thinking, which is simply more complex, more persistent than simple touch, or can be understood as a highly complex, highly dynamic sense or feeling. The brain's ability to think evolves from simple external sensations, bit by bit, to complex consciousness.
Why does the brain need consciousness and attention?
So why do creatures need this "feeling of thinking", I think the root cause is that the biological brain uses a special way, electric pulse, for information transmission. Because of this physiological characteristic, the brain must have the ability to select important thinking information and maintain the continuity of thinking.
Many people know that nerve cells rely on electric pulse to transmit information, but I bet most people are not interested in thinking about how different this information transmission mode is from computer systems. It has several key features:
- Brain neurons must continuously emit electric pulses to maintain the operation information of neural networks. Unless new synapses are generated by a large number of electric pulses, and the information is solidified in the neural network structure (such as form new memory), the information generated by the thinking can be used for subsequent thinking processes.
- Brain neurons can not only enhance the electric pulses of other brain neurons, but also inhibit the electric pulses of other brain neurons.
- Electric pulse not only includes the information of YES or NO, but also includes information in their frequency, which greatly increases the amount of information they transmit.
Brain thinking is just like our other feelings, a lot of state changes are not perceptible. For example, when we touch something, even though only the hand feels it, the whole arm actually drives the finger to serve this activity. Thinking also contains many unrealized parts, roughly equivalent to what we usually call the subconscious. In other words, when people are doing complex thinking, they will run multiple thinking tasks at the same time.
The first feature of neurons determines that they are "unsuitable" to be shared by multiple thinking tasks, because it will cause interference or even conflict between electric pulse signals of different thinking tasks, which leads to a competitive relationship between various thinking tasks. An effective thinking process requires a main line of thinking. Therefore, the human brain needs a kind of ability to distinguish and maintain the main line of thinking. At the same time, it is necessary to moderately suppress other thinking tasks in order to avoid other thinking tasks (subconscious) from interfering with the main line of thinking. (Thinking missions themselves may also suppress other irrelevant brain regions and thus suppresses other thinking tasks, but I am not sure about this.)
In addition, electric pulses may be interrupted at any time, so critical information must be maintained. The brain is like a computer. It stores data redundantly, but its temporary storage space will be covered by new data at any time, so the brain needs to pick up the most important data at any time and put it in a key information area.
The ability we have evolved for this is consciousness and attention mechanism. Specifically, when there are multiple thought tasks at the same time, the brain will analyze the most important task as the main line of thinking, strengthen it and suppresses other thinking tasks. It may also be that the thinking tasks are mutually suppress each other, after multiple loops of brain circuits, leading to the formation of the main line of thinking. It is also possible that both mechanisms work, but the result is that a main line of thinking must be identified, which is also called all-or-none, because once other thinking tasks seize the attention, the suppression signals they emit will inhibit or even destroy the main line of thinking. That is why the human brain can only feel a certain consciousness at a certain moment, and why humans are not suitable for doing multiple jobs at the same time.
For programmers, the main thread of thinking can be understood as the main thread, while other thinking tasks are asynchronous sub-threads or fibers, but the status of the main thread and sub-threads can be switched at any time, and each other will try to seize the priority and computing resources.
Other features about the attention mechanism:
- Only one of the thinking tasks is more important and obviously overwhelming other tasks, the state of concentration state will appear. Otherwise, people will often be distracted, that is, the main line of thinking often switches between the various thinking tasks.
- And when we are in a state of distraction, consciousness and attention mechanisms can remind us: "Pay attention! Concentrate on what we do now!" This is the key ability to accomplish important tasks.
- Continuous attention is a very advanced intelligent performance, even young children can't do it well.
- Nervousness and anxiety help to reinforce important thoughts, which may be important aids to human attention and concentration.
There are many other interesting topics about consciousness, such as the screening mechanism of consciousness. But these problems are too complicated, so they are left for brain neuroscientists to study.