“The man who sees his neighbor only as an aggregate of atoms cannot have the same conception of his real self. He thus arrives necessarily at a fundamental contradiction.”

                                                            - F. Husemann

 

 

 

Introduction

            There is a state of consciousness in which one could be or experience anything imaginable. This state encompasses the ability to dream (1). The dream state is quite remarkable and incorporates infinite possibilities for the dreamer within each of us. Nietzsche (1844-1900), a German philosopher, points out that dreams were a puzzle since “the ages of rude beginning of culture” when “man believed that he was discovering a second real world in a dream...(2).” The question that human beings were wrestling with since then is: why do we have dreams and what, if anything, do they mean. On the one hand, there are a number of prominent scientists, such as Drs. Allan Hobson and Robert McCarley of Harvard University, who argue that we dream for physiological reasons only and that dreams are nothing more than “meaningless biology” lacking any psychological content. I will refer to this as the materialist view of dreams. The opposing view comes from a large number of psychoanalysts that follow Freudian thought. They believe that we dream for psychological reasons and that any dream can and should be interpreted because it is a road to “the self.”  By applying Karl Popper’s philosophical framework of three worlds, I will construct a position which recognizes that dreams have physiological, as well as psychological determinants. I will also emphasize the interaction between them and hypothesize as to what this interplay spawns.  Such an approach lets one explore the problem from more that one angle, thereby allowing a more “truthful” synthesis of the various pieces of our current knowledge of dreams as well as our conception of “the self.”

 

 

                                                            Exposition

Part 1:  The Sleep cycle and Dreams

            Before examining any dream theories, we must have some knowledge of the nature of dreams and the stage of the sleep cycle during which dreams occur. 

            Dreaming is defined as “a sequence of sensations, images, emotions, and thoughts passing through a sleeping person’s mind” [1](4). The two important constituents of dreams are the sequence of perceptions and the presence of hallucinatory imagery, that is visual or auditory in nature. Dreams occur in the stage of the sleep cycle called REM sleep or paradoxical sleep. The subjects who awake from another stage of sleep called NREM sleep (occurs before REM sleep) do not describe their prior experience as dreaming (4).

            According to biologists, consciousness is “an ability to react to the environment.” This ability is temporarily suspended during sleep and thus dreaming can be thought of as an unconscious process (5). Brain waves, eye movements, and muscle tone, are the three major measures of sleep that are used in its study. From the polygraph records of the two major stages of sleep, NREM and REM sleep, it is apparent that eye movement is much more intense during REM sleep (in fact, the letters stand for rapid eye movement). During wake periods, muscle tone is high relative to NREM muscle tone, which can be considered to be moderate. However, during REM sleep there is no significant muscle tone and the sleeper can be considered virtually paralyzed (6). The central paradox of REM sleep is that there is an increased responsiveness to sensory stimuli in the thalamocortical region of the brain (much like in the awakened state) despite the fact that there is a lack of cognitive responsiveness to sensory stimuli (7). Basically, our body is intensely responding, we are having all these emotions and images which seem so real....all while we are paralyzed from the neck down (8). Also, it should be stressed that everyone dreams; the people who claim that they do not, simply never wake up during their REM sleep to remember it (9).

 

Part 2: The Two Theories of Dreams: Freud versus Materialists.

            The oldest comprehensive theory of dreams was formulated by Sigmund Freud (1856-1939), an Austrian neurologist. In order to understand Freud’s view of dreams we must first look at his conception of how the brain works. Today, it is a known fact that two types of neurons are present in the nervous system - excitatory and inhibitory. Both types of neurons communicate through transmission of electrical signals. The neurons can either do so spontaneously or by receiving excitatory signals from other neurons. The difference is that excitatory neurons transmit signals which cause increased activity in other neurons, while inhibitory neurons send signals which decrease or inhibit the activity of other neurons. The nervous system is made of an extraordinarily complex network of intricate interconnections between billions of excitatory and inhibitory neurons (3).

            During Freud’s time, only process of excitation has been discovered while the process of inhibition was not even hypothesized. Drawing from the model of a completely excitatory system, Freud concluded that “nervous energy” (caused by excitation due to, say a, thought) could only be discharged by some sort of motor action. An outcome of this theory is that once you got a notion in the brain, it would be passed around the nervous system until you decided to face it and do something about it, or until it found a way to manifest itself, either in an unintended action, such as the famous “Freudian slip,” or in form of visual imagery, such as a dream (3).

            Of course, today we know that the nervous system which generates “blasts of energy” could not exist since it would produce persistent, uncontrolled seizure activity! However, from the excitatory model of nervous system, Freud’s theory about the nature of dreams can logically follow (3). According to Freud, every dream has meaning and carries a message manifested by unconscious processes. The content of the dream is a metaphor for some disguised, or rather repressed, wish of the consciousness. In order to interpret a dream, one has to reason backwards in a process of interpretation known as “free association” (this method is still practiced in modern psychoanalysis). For example, if a person dreamt of a key, Freud would ask what was the first thing which came to mind in connection with a key. A person would likely answer that what came to mind is a lock. Freud would then reason about the connection of the two and about the symbolism involved. He would likely conclude that the “lock and key” imagery expressed the person’s wish to have sex! (3)

            Freud thought that the function of dreams was to allow the release of repressed thoughts and impulses which cause excitation in neural activity. The force which causes dreams to occur was, in all cases, an unconscious and instinctual wish. The only way that the wish could be subdued is by the release of the “nervous energy” that was caused by it. Also, Freud noted that “though the number of symbols is large, the number of subjects symbolized is not large. In dreams those pertaining to sexual life are the overwhelming majority...They represent the most primitive ideas and interests imaginable (10).” Therefore, the same dream that is dreamt by two different people (or the same “dream symbol”) meant that they both had the same repressed wish. This wish, whether sexual or otherwise (although, Freud thought that the wishes to a large extent were ultimately sexual in nature), was the force behind every dream and therefore all dreams must contain a necessarily meaningful message (3).

            Today we know that dreams are not triggered by psychological factors, such as repressed desires or wishes, but rather by a purely biological process - REM sleep. We can no longer infer that wishes play a role in dreams because they do not spur dreams. If taken further, we can no longer assume that every, or any dream for that matter, has any significant meaning (3).

            Another problem with Freud’s theory can be formulated through Karl Popper’s philosophy. According to Popper, the best theory is one that is most refutable. The major flaw in Freudian theory is that it is immune to criticism. For instance, if I propose that my dream of the lock and key imagery is not of any significance or give it any alternate meaning, a Freudian will just reply with something like this: “sure you want to think that, but you very thought of this just points to the fact that your are so much more sexually repressed!” In fact no matter how one tries to refute Freud, the very construction of his theory is such that it is immune to refutability[2] (23). Popper had a very skeptical of “unrefutable” theories, such as Freud’s, and referred to them as “myth” (19) : “Science is not a system of certain, well-established statements...Our science is not knowledge: it can never claim to have attained truth, or even a substitute for it, such as probability...We do not know we can only guess (24)”

            The latest neurophysiological theory of dreams, which is in direct opposition with Freudian concepts, was developed by two Harvard University scientists - Drs. Allan Hobson and Robert McCarley. According to fully materialist Activation-Synthesis Model, dreaming is caused physiologically by a “dream state generator,” which is located in the brain stem. It is “on” during REM sleep, while all sensory input and motor output are blocked, and the neurons in the cerebral cortex are activated by random impulses that generate sensory information within the nervous system. As Hobson and McCarley put it: “the activated forebrain then synthesizes the dream out of internally generated information, trying its best to make sense out of the nonsense it is being presented with (3).”

            The logic used in the development of the Activation-Synthesis Model stems from the predictable regularity that is observed in the triggering of a dream state. Hobson and McCarley stress that “the motivating force for dreaming is not psychological but physiological since the time of occurrence and duration of dreaming sleep are quite constant, suggesting a preprogrammed, neurally determined genesis (3).”

            Hobson’s and McCartey’s treatment of symbol formation is also in direct opposition with Freudian conception. They believe that “bizarre features” of a dream world are simply a reflection of the bizarre state (the bombardment with internal excitatory signals, etc.) of the dreaming brain. That is, in the construction of a dream “the forebrain may be making the best of a bad job in producing even a partially coherent dream imagery from the relatively noisy signals sent up to it from the brain stem.” This implies that dreams have no emotional content since they are triggered only by sensory and motor aspects of bodily activity (3).

            Hobson’s and McCarley’s notion that “dreams were after all merely senseless, random accompaniment of the autonomous electrical activity of the sleeping Central Nervous System” is not the whole story. Based on our knowledge of brain physiology, there is no doubt that the Activation-Synthesis Model is right by dismissing the Freudian notion that dreams are instigated by a wish. In a sense, what happened is that “myth”  was converted to science through subjection to critical examination. This is what Popper believes is the general progress of human knowledge (19) However, before regarding dreams as meaningless productions, which is what Activation Synthesis Model is doing, the function of dreams and the factors that influence their synthesis must be further examined (3).  In doing so, I will now turn to Karl Popper’s theory of the three worlds and their interplay, which will give the necessary framework for assessing the theory.

Part 3. Karl Popper’s Three Worlds

            In his essay “Knowledge: Subjective versus Objective, ” Karl Popper characterizes three “worlds.”  The first world encompasses physical objects or physical states. This, in the current example, would be the world of the brain states (for instance, particular neural conformations).  The second world is that of “states of consciousness” or subjective mental states, i.e., the Freudian physiological significance of dreams,  and the third world is of “objective contents of thought.”  Popper admits that his world 3 resembles Plato’s  realm of immutable Forms, which are, as in the case of the “inmates” of world 3, “truths-in-themselves.” That is, they are “absolute truths.”  However, unlike Plato, Popper regards world 3 as a human creation. Thus, theories, problems, and artifacts in general belong to world 3 (16).

Part 4: The Self in Relation to the Three Worlds

            In his essay The Self, Popper extends his notion of the three worlds to the conception of “the self” (22)  Such an extention is particularly applicable in the examination of dreams because dreams, regardless of how one thinks of them, are in fact, some sort of a creation of the self. That is, dreams are a manifestation of some part of the being, whether physiological or physiological, or both.   

            Popper  starts his argument by noting that “selves exist. ” He goes on to use the example of overpopulation which implies that at this stage he is thinking of the physical, world 1, existence of the self. Here “the self” is defined as that which is contained in space and time; overpopulation is a testament to this.  Popper goes on to attribute to the self “hopes and fears, sorrows and joys, dreads and dreams...”  These are all attributes of world two[3]. Popper’s main thesis in this essay is that the self is anchored in all three worlds, especially in world 3 (22).

 

Part 5:  Development of Dualism

            The relationship (or the lack of it) between the physical world 1 and the mental world 2 has been at the heart of philosophy for quite some time. Since the development of neurobiological theories of how the brain works, a new frontier to attacking the question has arisen. We now know that certain mental changes are accompanied by physical changes such as electrical transmission by neurons in the brain, and visa versa. This is basically the foundation of the Activation Synthesis Model .

            The bases of distinctness of world 1 and 2 has arisen from a notion that science can not in principle observe one’s experiences. For example, it can not fully capture a person’s particular experience of dreaming. Perhaps, neurobiologists can pin point every neuron firing, the frequency of its signal, combinations of neurons involved, etc. , when a person is experiencing a dream but what they can not summarize is how  it feels for that person to have the dream. Any information that would lead any other person to know that person’s experience  would only give them their own experience.  So in essence, no amount of information could give direct evidence for what the particular experience of an individual’s dreaming is really like. This is the argument for privateness of inner experience which states that any experience is private, limited to a particular person and thus can not be fully reproduced. Given the privateness of inner experience, our experiences can not be totally physical. So any  experience one has, such as dreaming, is essential to the person having the experience. Since experience cannot be totally physical, the self must consist of two different entities- the mental and the physical, contained in world 1 and world 2, respectively. This view is known as Dualism (20). Dreams, on a dualist account would therefore have consist of both the physiological and psychological components.

 

Part 6:  Popper’s Three World and the notion of interactionism

            The Popperian view of the worlds of the physical and the mental stresses, which is of great importance when thinking of a dreaming self, encompasses the notion of interactionism- the theory that mental and physical states interact. The notion of interactionism and Popper’s world 3 are an interesting add on, or rather an extension of the Dualist thesis. As we will shortly see, it gives great insight into the nature of dreams.

             In his book The Self and its Brain, Popper uses an example of a toothache to illustrate the interaction between world 1 and world 2. If a person has a toothache, he is likely to see his dentist. This process entails a number of actions and movements of the body which are clearly physical. The caries in the tooth are material, “physico-chemical process,” which leads to physical effects. However, it does so by way of your mental state, i.e. painful sensations, and your knowledge of existing institutions such as dentistry (21).

            Popper himself points out that examples such as the one mentioned above are “very obvious, even trivial.” What is important to realize is that some philosophers anchor the self and its dreams into both the physical world 1 and the mental world 2.  However, while admitting to the existence of mental states in the self, they deny their interaction with world 1. This is in essence what Freudian followers are doing. They are disregarding that  the medium in which the dream occurs in is a physiological one -  the world 1 of the dreaming brain constituted in  the physiological phenomenon of REM sleep.  This view Popper calls “as unacceptable as the denial of the reality of mental states,” i.e. what the Activation Synthesis Model is doing. By dismissing any psychological contents of dreams, followers of Dr. Hobson and McCarley, are in essence dismissing the presence of mental states in a dreamer.   

            Hobson hypothesis that the likely function of dreams has to do with

“the sign of genetically determined, functionally dynamic blueprint of the brain designed to construct and to test the brain circuits that underlie our behavior - including cognition and meaning attribution” is a direct testament  of a view known as materialism. Before I assess the validity of this view, I want to briefly outline the principles of materialism and suggest possibilities for why this theory of dreams found great success among scientists.

 

Part 7: Materialism

            A materialist holds that all entities are made of, and are reducible to matter, material forces, or physical processes (18). The Materialist explains “the self” in terms of small physical aspects which make it up.  Therefore for the materialist there is no concept of “the mind,” world 2 - just the physical aspects which make it up, namely the brain. The treatment of the self and its dreams in terms of world 2 and 3 becomes irrelevant since the materialist attempts to fully explain the self in terms of world 1.

            The enduring appeal of materialism is largely caused by its affiliation

with the sciences that contribute to most of our knowledge about the world. Investigators involved in the physical sciences employ a materialist methodology. They try to explain a phenomenon in question by the appeal to the physical conditions alone. Also, the tremendous progress in the field of materialistic biology and biochemistry increased the appeal of materialism (19). Francis Crick, a biologist who, along with Watson, was the first to unravel the structure of DNA, pointed out that “The ultimate aim of the modern movement in biology is in fact to explain all of biology  in terms of physics and chemistry...” (17). By explaining away dreams as chemical processes which must occur in the brain in order to “test its circuits,” the Activation Synthesis Model is doing just that.          

 

Popper’s Critique of Materialism

            In defense of his theory, Popper argues that  materialism is unsatisfactory for it does not do justice to World 3 objects; it does not explain the actual theoretical contents and their objective logical relations which are exhibited between the abstract character of World 3 objects. I  want to briefly outline Popper’s argument because of its direct relevance of how one thinks of dreams. 

            In his defense, Popper uses a revised form of Haldane’s Refutation of Materialism (21) presented in a dialogue between an interactionist, like himself, who believes in the interactions of the three worlds in relation to the self (and to the rest of the world, for that matter),  and a materialist who argues for the existence of world 1 phenomenon only.

            The start of the argument is the assertion of both parties that learning, such as in the form of linguistic interaction,  and forces, such as natural selection, play a direct role in the emergence and formulation of  logical thinking.  So a brain, like a computer, is built in such a way that it operates under the principles of logical relations. Both parties then admit that computers and human brains make mistakes. 

            The interesting twist to the argument comes when the Interactionist asks the Materialist what computers and human brains fail short of when they actually make a mistake. The exhaustive answer entails the notion of a failure in some standard of logic.  That is, the failure in the logical relation in question which is by some means established to be a standard . Also, is important to note that the mistake itself is deemed as such precisely by its inconsistency with “the standard of logic.” However, the materialist can not admit that the standard is accepted because it is valid for such an assertion would lead to precisely what he does not believe in, the existence of the abstract world 3 which entails concepts such as validity. Instead the materialist is forced to frame the answer differently and admit that the standard exists within the brain states of people: “the states or dispositions, which make people accept the proper standards. ” 

            The materialist must answer that valid logical relations “arise from such things as natural selection of say “certain ways of verbal behavior” and “of connecting some beliefs with others” ( according to the materialist all these are world 1 phenomenon of the human brain ) Also, these relations arise out of their proved usefulness since forces such as natural selections insure this. Popper then notes that if one admits that conformity with logical standard is useful (the difference between a useful and non useful computer is precisely this...the non-useful computer makes mistakes all the time for it does not act in accordance with standard logical relations) for survival, one is also admitting the usefulness of the logical standards themselves and thus he is admitting of their “real existence.”  This implies the “real” existence of world 3. So the problem for the materialist is that he can not admit that a system such as logic, that is, an abstract world 3 system, can exist over and above the particular system which created it, such as the evolutionary patterns of the brain and particular ways of “linguistic behavior” (21). The fallibility of human brain or the computer denotes a lack of an established logical relation which must be separate from the system which created it for if it was contained in the system, mistakes would likely not occur. So, the postulation of world 3 is necessary for explaining  what Popper believes to be one of the most important concepts in the understanding of the self - how the self uses logical relations to frame theories rendering the ability of self reflection and of the knowledge of the world.

            Another argument that Popper uses against the materialist involves the theory of language developed by Karl Buhler (a teacher of Popper).  In this theory, language is defined as having four functions (Popper adds the  fourth one and the first three are developed by Buhler). The first is the expressive function, the second is the signal or the release function, the third is the descriptive function, and the forth is the argumentative function. (21). To properly evaluate Popper’s argument it is necessary to briefly outline what the four functions entail in relation to the self.

            The expressive function has to do with expression of some “inner state. ” Part of being a self involves “inner” expression and we engage in such with any action, and in this case it is caused by expression of the inner state though language[4]. The signaling  function is a higher level language function  for it presupposes the expressive function. Basically, our linguistic self expression, or any other self expression for that matter, leads to a particular reaction. An example would be yelling when you’re in danger. In such cases, the linguistic self expression has manifested, or rather taken the form of a signal. The descriptive function is even higher up for it presupposes both the expressive and the signaling function. This is the function which actually makes statements true or false according to some standard of validity (note that the “concept of validity” is a world 3 phenomenon)  and invalidity, both of which are manifestation of the forth argumentative function (21). 

            Popper notes that in explaining the self in relation to the linguistic phenomenon, the materialist can only utilize the first two functions because he must give a strictly physical explanation of the language phenomenon. Such a characterization does not extend into the last two higher levels of language. Popper notes that the result which follows is a “disastrous” flaw in the materialist’s thinking. That is, if language is seen only as expression and communication, the materialist fails to grasp the entirety of the phenomenon of human language as opposed to animal language - its ability to construct true an false statements and  to produce valid and invalid arguments (21). 

            Popper does not claim to have refuted materialism by these two arguments. However, he has succeeded in showing that the materialist argument for the existence of just the physical world 1 is insufficient to fully grasp the constituents of the self such as the ability for propositions of logical relations. The second argument clearly illustrates that materialistic assumptions  are also insufficient for grasping one of the most intricate and complex phenomenon of the self - language. Through language and the use of  logical relations we learn of the world and thus get a step closer to knowledge of our “selves.” Popper showed that materialistic ideology is insufficient to understand both of these phenomenon of the self. Popperian conception of the interaction of the three worlds is a much fuller representation of the concept of the self. I would now like to apply it to the particular phenomenon of the self - dreaming.

           

Assessment of the Activation Synthesis Model in light of Popper’s ideology

            Various evidence certainly suggests that dreaming is more than “genetically determined.” The fact that we, at some times, have dreams with an eloquently constructed story lines, as well as the fact that dreams do influence behavior in many instances, point to the idea that higher order mental functioning has the ability to influence a lower order functioning of the “dream state generator” of the brain stem (3). This is analogous to the Popparian conception of expressive function underlying a higher order perception.

            In fact, dreams very often have a profound effect on how one relates to the outside world. One dreamer recalls: “when my children were about nine and four I had a dream that they were crossing the street at a crosswalk with friend of theirs. All three got hit by a car and were killed. I recall waking up and being absolutely terrified. I jumped out of bed and went to check on them. They were both sound asleep and in good health. None the less the fear would not leave me so I did something that I ready do, I knelt be my bed with tears running down my face and prayed to God that this dream never come true” (12).

This mother’s entire outlook on life was changed by her dream; she constructed theories and made “logical connections” with reality. Even if dreams were just a world 1 phenomenon as the materialist believes, he can not deny the fact that the world 1 spawned some physiological response (world 2) which manifested itself in the formulation of a concept, i.e. a new outlook (world 3)

            Stories like the one mentioned are numerous. It is apparent that many dreams give people a profusion of various information about themselves and their relation to the outside world that they can not know from the genome alone (13). As already mentioned, Popper emphasizes  that world 3 is a human creation, like in the case of a construction of a new outlook after a dream. So by extending the notion of interaction of the first two worlds with the third world in a dream,  the central role of the dream in creating the knowledge about the world, and about “the self” is brought to light. 

            Popper points out that we get little out of self-observations because the outcomes provide superficial answers. For instance, if you are asked to “observe your body”  you will get little out of such an inquiry due to the “evasiveness of the ego.” That is, one can not properly evaluate oneself, and any product of that self, such as a dream, without the development of some theory. Popper concludes that we “become selves” through the formulation of theories about our own nature;

this is a world 3 process (22).

            Another point to consider is that the synthesis of dreams, while influenced by the genome, is also influenced by a particular person’s experiences. Perceptions gained through these experiences play a role in the type of a dream world that the brain makes up. The genome is there to establish the particular types, amounts, and various neural connections present in the brain.  In what ways and which of these connections are used is determined by each person’s unique experiences which effect behavior by producing a permanent change in the brain (after the experience is detected by sensory nerves). This change may alter neural connections in the brain or alter how they work and thus it will influence how one dreams. However, in any discussion of dreams, it is equally important not to forget the genetic factors that are stressed by the Activation-Synthesis Model.

            It has been long apparent that the genome does influence what and how quickly and easily one learns. It must also influence how one dreams by providing the nervous system with the tools (neural connections, etc.) from which to create dreams (13). The point to note is that the phenomenon of the brain making things up for itself, which is evident during dreaming, has to do with both the genome and experience and how they interact. Most importantly, one must heed how the two play a role in the construction of a new outlook (world 3) which ultimately in some way modifies the genome (world 1) and experiences (world 2).

             Popper notes that “the self” is a result of “inborn dispositions,” which are of world 1 character due to their rooting in genetics, and the interactions with world 2 of other people. However, the process of becoming a self must be anchored in a person’s  contact with world 3 of theories such as the theory of that which the self produced- the dream.

             The case of lucid dreaming, which is the state of dreaming while knowing that you are dreaming (14), also shows that there is more to the story than what the Activation-Synthesis Model can offer. Lucid dreaming has been proven to occur due to technology which lets people signal through electrodes attached to corners of their eyes (by prearranged eye movements) when they realize that they are dreaming (15). If dreams were simply a result of the forebrain ”making the best of a bad job in producing even partially coherent dream imagery from the relatively noisy signals sent up to it” from the brain stem, then how could a person know that they are dreaming, be able to exercise volatile choice in a lucid dream, or carry out a previously planned course of action in a dream? Also, studies of lucid dreams indicate that dreamers are at times able to have their own intentions, ideas, and feelings. These feelings can not simply be attributed to random brain stem stimulus, but rather they might be a response of some higher order perceptions (3).

            As is evidenced, dreaming has both physiological determinants as expressed by Activation-Synthesis Model, as well as psychological determinants. These two factors are played out in astonishingly unique ways in each individual. Therefor, it is hard to believe that the same symbol that appears in the dreams of two different people actually means the same thing, if anything at all. The brains of two people are extremely different, not only due to genetic differences but also due to their relation to the external world (the experiences of each person are very unique). The other fact that adds to this uniqueness is how each of their brains uses the input of genes and experience to synthesize the dream world (13). Taking all these factors into account, with the added knowledge of the complexity of the nervous system, it becomes apparent that the notion of universal dream symbols is quite shaky.

            Another point to consider is that the construction of a world 3 as a result of a dreams adds to the intricacy of the phenomenon. Dreams embody a synthesis of the self  that is manifested at  the physiological , psychological, and “theoretical” level. All these give us a glimpse into what we are like. We have inside us, through the power of dreaming and imagining, a unique ability to experience the world like no one else has and to use ourselves as a subject of exploration (13). The self is more than just “an aggregate of atoms” and the many levels of the dreaming self are certainly a testament to that.


[1] It should be noted that the use of the word “mind” in this definition produces some ambiguity. If one thinks that the mind and the brain the same thing, as materialists do, then the terms are interchangeable. However, if this is not the case, then one runs into a semantic problem.

[2] It is interesting to note that other famous doctrines such as Marxist ideology, follow the same pattern of immunity.

[3] It is important to not that in this essay, dreams are placed in world 2. However in his later book “The Self and Its Brain, ” Popper examines the physiological aspect of dreaming.

 

 

[4]Dreams too, according to this theory, have an expressive function of the “inner state” manifested in form of dream imagery.