What is this idea?
Obviously, it is not milky white and translucent, it can go through the wall and even climb out of the TV. According to Descartes, I am a "thinking thing", but Descartes thinks that this thinking thing is not made of matter, but another kind of immaterial existence. Today, we don't think so We all think that there is no such thing outside the material world, but all that really exists are physical objects.
The question now is, the mind is also made of matter, so what kind of matter is it made of? In what way?
The most promising substance to form a brain is the brain under the skull.
But the question is, aren't the spinal cord and peripheral nervous system, which also constitute the central nervous system, important? If it is not important, then if we destroy a part of the brain and find that this person still thinks he is alive and normal, then this part of the brain is not important? This "brain chauvinism" of the same theory is difficult to defend. If extreme, we can even have "neocortex chauvinism" and "prefrontal chauvinism".
If it refers to only one biological tissue, it is said that this is the mind. This will lead to a very troublesome problem. Many tissues in the body are connected. Why do you point to this piece and say it's the brain, but the one on the right is not?
Then came the most mainstream theory in academic circles, functionalism. Functionalism holds that the mind is not equal to matter, but a function. Just as the function of an axe is to cut down trees, the mind is the function of a complex system, and the human brain is such a complex system. This theory has many advantages, one of which is multiple realization. For example, an axe can cut down trees, and so can a saw. Strictly speaking, as long as it is a powerful weapon. The same is true of thought, which is the function of a system. This system doesn't have to be composed of substance A, substance B can, and it doesn't have to be composed of mode C, and mode D can.
Now the problem is coming again. Is the mind just a function of the brain? What about spinal cord and peripheral nervous system? What exactly is psychological activity? What is the content of our thoughts? What are our subjective feelings?
The grand representation of cancellation, "heart" or "I", is an illusion. Just like unicorns, the word Mind (no matter what language it is spoken in) has no real equivalent. Even all our daily psychological activities have no real counterpart. Suppose neural activity A happened, and then you said you heard Pink Floyd's music. Nerve activity B happened, and you said you saw green. Nerve activity C occurs, and you say that you feel someone touching the outside of your calf. But this does not mean that every psychological activity has a one-to-one correspondence with neural activity. In fact, only neural activity really exists, and neural activity X occurs, which leads to the simultaneous occurrence of neural activity Y, and then some muscles contract and body fluids are secreted. Maybe when nerve activity X happens, you will report that you feel hungry, but maybe the next time X happens, you will report other feelings or not. When you sleep, your brain is still active, but you don't actively report any psychological activities in the form of words. Those psychological activities reported in written form actually don't exist. Even if others report the same psychological activities, their neural activities may be different from yours, because their neural networks are different from yours.
Not just feelings, even beliefs. The belief that "I believe the sun rises in the east" is actually just a kind of nerve activity, and you don't need to have "the sun", "the east" and "me" in your brain. Because people's psychological activities do not depend on a "language of thought", when you are consciously thinking, you are not necessarily talking about your inner language of thought. All psychological activities of people are actually nerve activities. However, due to the development of science, we don't even need to think that psychological activities are just nerve activities. Perhaps the activities of other organs or organizations should also be counted as psychological activities. After all, the receptor, effector and intermediate neural processing are equally important for completing the stimulus-response process. Sensory organs such as eyes and motor organs such as tongue (which also has sensory organs such as taste buds) may be as important to your thinking as the nervous system.
Now we can think about some interesting questions, such as do animals have hearts? Does the artificial machine have a heart?
If the mind is the function of a specific system, then it is obvious that both animals and artificial machines have minds. Even a simple paramecium can be said to have a mind. We can't draw a dividing line, saying that things on the left side of the dividing line have no brains, and things on the right side of the dividing line suddenly have brains, because the complexity of these systems is continuous. An atom is a system, chloroplasts are a system, so are paramecium, apple trees, monkeys, air conditioners, smartphones and humans. These "intentional systems (see Dane's works for details)" can all be regarded as whether there is a heart or not. Whether a system has a brain or not depends not on the system itself, but more on human beings. Because human beings can talk, they will say "A has a heart, B has no heart", but this judgment is arbitrary.
In my favorite phrase, only people who can speak Chinese are qualified to judge what spirit is. English speakers can only regard some systems as intentional systems of "spiritual carriers".
But are these systems thinking the same as human beings?
The thinking of electrons is different from that of protons, thermometers from computers, air conditioners from dragonflies, Escherichia coli from daffodils, crocodiles from elephants, and even chimpanzees, close relatives of human beings, are completely different from humans. If we want to make a narrow interpretation of the mind, then we can think that only human beings have a mind, because only human beings have a complex language system. This complex language system is so important to the function of the mind that we can suspect that a person who doesn't know the language (such as the language area of the brain is damaged) even has no mind.
Finally, finishing the full text:
The mind is the function of the intentional system, and the human mind is a very complex and unique function of the intentional system.
Human thinking is unique, because human beings have produced language.
The reason why human beings produce language is related to highly complex nervous system, evolutionary pressure and some coincidental factors.
Whether other things (systems) have souls is actually an unimportant issue, because there is no dividing line between things with souls and things without souls in the universe. Because only humans can talk, they can decide what has brains and what doesn't.
The activities in people's minds, such as propositional attitude (I believe XXX), feelings (pain, happiness) and so on, actually do not exist. What really exists is physical activity, physiological activity and nerve activity, while psychological activity does not exist, but it is an effective tool to help human beings gain evolutionary advantage, so we don't have to be pessimistic about this conclusion.
Supplement: Philosophy of mind is the most popular field in philosophy at present, mainly because scientists have not performed well in explaining the task of "mind", while philosophers have robbed psychologists of their jobs (fog) in order to avoid being discriminated by physicists. In this field, there are many interesting problems, such as free will, subjective sensitivity (such as the feeling of seeing red), memory, consciousness, identity and so on. If you are still interested in this problem, you can find some papers on philosophy of mind to read.