To achieve his rational goal, Descartes rejected materialism. This meant that Descartes rejected both the idea that the body is a material substance and that the mind is separate from the body. Descartes understood materialism as the point of view according to which the body is a material substance, that the mind is different from the body and that the body has nothing to do with the mind. Descartes believed that in a sense, the mind is not a separate substance, but a substance that exists in the body. To say that the body is material, Descartes believed, means to say that the mind is not a rational thing, but a thing that can be controlled with the help of the body. In other words, the mind is a rational entity that can be viewed as separate from the body. In his Treatise on Method, Descartes said: «One thing cannot think of another thing independently». Descartes considered reason as one substance, rational. Descartes argued that if mind were a separate substance, then we could create ideas about other things and things other than mind. This would be impossible for the mind, because the mind is essentially a body. «It is necessary that the mind, as the rational faculty of the body, belong to the body; that it, and not the body, was the substance of the mind; that it is a material part of the body; and that he should be a part of the body, like that part of the body that consists of rational faculties».
As I mentioned earlier, Descartes did not adhere to the idea that the mind is a separate substance from the body. This is a decisive moment in Descartes’ understanding. When he discussed mind and body, he insisted that there was a difference between the two. He believed that the mind is a rational thing, but inseparable from the body. Rather, the body is an effective cause, a tool that the mind uses to achieve its goal. «The relationship of things to each other is always determined by the nature of things. It is intelligence to produce what is in the mind, what makes them change, what makes them exist». Mind and body are intelligent things, but not separate substances. Descartes believed that although we can think of mind and body as if they were separate substances, mind is the effective cause of the body. The mind is the inner force that exists in the body and through which it is built. An essential part of Descartes’ understanding of mind is that mind and body are not separate substances. This is not to say that mind and body are separate substances. They are one and the same substance. In a sense, the body is simply a tool that is used to help the mind achieve its goal.
These are words that we know come from the Latin verb rerum (asire in English). Feelings alone, and also only imagination, will not do anything, neither see, nor hear, nor think, but must be connected together with the intellect (lat. Intellectus), and they will be ready to produce sensation. For example, if you want to find out whether there are two things or not, you have to reason to do so: the mind, which is of the same nature as the imagination, will cause the sensation of the existence of two things; because a reason alone, if you set it up to conjure up a sensation, will cause both sensation and doubt; but doubt alone has its own nature. The difference between existing and non-existent things is this: every thing that exists has a cause, and every thing that does not exist has no reason. Therefore, there is a reason for everything that exists, and there is no reason for everything that does not exist. So, this reason has existed from eternity; for each cause, it is already present and remains after a series of things: for example, those things that were caused come to their end and die. Therefore, this cause of things exists from eternity, and this cause of things does not exist only from time.
In the second part of the Treatise on Man, Descartes develops the concept of reason, which combines reason, imagination and thought. This is the first attempt by modern philosophy to develop a theory of mind, because, in addition to believing in what is believed to be true, the object must also judge whether it possesses that property. Descartes’ theory does not attempt to create an object called the «comprehensible world» that does not depend on the mind that perceives it, but rather represents the mind’s perception of the transcendental mind.
In his earlier Reflections books, Descartes addressed epistemological questions about what knowledge is and how we acquire it, and how knowledge about external objects can be obtained. In the third book, he presents the idea of an inner mind (intelligible world) for solving the problem of cognition in the physical world. As he notes: «So, if I know this, I must also know that I do not know it; and if I know that I do not know this, I must know that I know it».
His solution to the problem of epistemological knowledge is that mind exists somewhere, which is itself a judgment, and that mind itself is a single judgment. This is the mind, and the mind is the domain of knowledge. Descartes’ theory of mind as the mind behind the world is to some extent a complete interpretation of the «mind behind the world» of Pythagoras, but Descartes’s theory is still sufficiently related to the idea of Pythagoras to qualify as a form of mind dualism and body. The story of how we can find out what is in the mind of the world in Reflections can be seen as a continuation of this.
Descartes begins the fourth book with the argument that, although the world seems absolutely solid, the principles governing all the complex phenomena that we perceive around us are not rigidly fixed. They are constantly being modified or transformed. As Descartes says in his article «An Essay on Human Understanding», the sun seems to move across the sky because the changes that occur in the fixed world that we perceive in general includes the movements of the planets and stars, and what he could describe these changes, as a continuous movement, would mean that the underlying substance is subject to constant change, and therefore is not absolute. Instead, the only substance that is not subject to constant change is the mind that we have about ourselves, the mind that is material. This mind is an understandable world, but not everything is clear, and those things that are incomprehensible are called «beings» or «active principle». The idea that mind or some other immaterial, non-causal principle should be responsible for the world that we perceive around us has been called «metaphysical materialism» or «materialism from within».
Descartes argues that we perceive objects not only as existing in the world in any objective sense, but also subjectively. This is because we are, in fact, attentive to the imaginary mind within us, which is separate from the visible world. Let’s take an example: when we eat something, our real sense of taste causes us to attribute the taste of the object not to it, but to our imagination. We actually see the object and sense the taste associated with it, so that we not only taste the taste, but also imagine that we are tasting it. In the dualism of the spirit and body of Descartes, the mind is the same as the real world as a whole, but the world is not identical to the mind as a whole. According to Descartes, we know what we are thinking, because «it is through thinking that our sensations are transmitted through the body system to the tongue and the gut.» We are no longer looking for the whole object, but our body as a whole. The perceived thing is the «inner», system of ideas, how they appear in our mind and how they are experienced by our senses. Descartes thinks of the sensory impression of an object as representing that object as representing that perception.
Descartes’ belief in materialism is simply a belief, and he admits that we do not know how our own consciousness can explain the comprehensible world, especially when it is connected with us in such a way that the material cannot be part of our mind. But to think that we can explain the world using an intangible cause is incompatible with our human experience, so Descartes assumes that there is a material cause. This is what he calls the non-material cause. According to Descartes, it is the cause of the movement of the sun, or the cause of a dream, or the cause of the invention of something, the cause of the universe.
Yet one of the most surprising features of Descartes’ ideas is that the material cause does not seem to have any reason at all, that the purpose of the universe is for the world to be as it is, without any external cause. Descartes does not provide any explanation for how the material cause arises in the first place, and he does not provide any explanation as to why the material cause must cause the non-material cause. However, as I suggested, what seems to be a simple axiom – «there is no external cause», is very difficult to establish in the materialist worldview. Most philosophers at least claim that we do not know how a material cause arises. But from the point of view of the materialistic worldview, no one can know whether a material cause arises in some primitive mechanism, or as a property of the universe, or as something that would arise if there were nothing but material, or as a result of a process, natural selection, or from an unthinking source such as spontaneous generation. There are many different possible answers to these questions, and they may all be correct, but we can never know for sure what the material cause is.
Consciousness and intelligence are very important concepts in our scientific understanding of the world. It is the main characteristic of the mind that it arises from consciousness. So we can see how a scientific understanding of the mind explains what it feels like to experience it.
However, consciousness and mind are not the same thing. They are not just different levels of the same thing. Consciousness is an experience of the mind, and it does not exist outside the mind. Scientifically, this is perfectly reasonable, because there is nothing in the physical world that can experience anything external to itself. Of course, this is not that easy, because there are many things that the physical world can experience, and in particular, the physical brain can experience things that are not physical at all. In the context of consciousness and mind, things like thoughts, beliefs, intentions, etc., are not just mental states. These are mental states that the physical brain experiences.
There is a striking contradiction between how the scientific understanding of consciousness relates to the nature of mind. Indeed, the scientific understanding of the mind gives us only limited information about how the mind can arise from the material world.
The mind and the material world arise in complex causal relationships. For one to arise from the other, they must causally influence each other. The mechanisms that cause the mind to emerge from the material world involve extremely complex processes that include many physical and mental properties and cannot be directly observed. As a result, the mind and the material world are not independent, and if the material world were not present, there would be no consciousness either.
There are some things that are important to the mind. Descartes identified several functions that, in his opinion, can be described as a function of the mind. These functions are the ability to induce change, retain in memory, combine disparate thoughts, and use the body to perform specific functions. These are the general functions of the mind. But Cartesian thought allowed much more. He admitted the possibility of a broader understanding of the possibilities.