The origin of consciousness. A review of several major theories and animal consciousness possibility and accessibility

Bachelor Thesis, 2006

23 Pages, Grade: 8,0 (NL)





1.1 Evolutionary theories of consciousnes
1.1.1 Introduction of Darwinian evolution
1.1.2 the possibility of Darwinian evolution of consciousness by examining the question of the function of consciousness
1.2 zombies: consciousness as an optional extra
1.3 Not separable functions

2.1 Human consciousness
2.2 Animal consciousness
2.2.1 Importance of the question of animal consciousness
2.2.2 Self-awareness
2.2.3 Theory of mind
2.2.4 Language and suffering




The origin of consciousness has come into main focus recently and is a widely discussed and controversial topic. This paper gives an overview of some of the most important theories of the origin of consciousness, including evolutionary and functional theories of consciousness emergence, theories of consciousness to be an optional extra and the idea of consciousness emergence by being not separable from higher-order functions. However, it will be shown that every theory faces its own, severe problems, which do not seem to be solvable in the near future. Furthermore, is the possibility and accessibility of non-human consciousness examined, with an emphasis on animal consciousness accessibility. It is shown that this question is also difficult to answer due to several limitations and further research is suggested.


Consciousness has recently come into the focus of scientific discussion after being neglected for many years. In particular, the question why conscious beings (all the time including humans) are conscious and how consciousness could have emerged has been of interest.

However, there is a general problem with conscious research, which is an important reason why consciousness was neglected for such a long time. The study of consciousness seems to be more difficult than other research. One reason is that consciousness is difficult to define in the first place. As David Chalmers (1998) puts it ‘trying to define consciousness is fruitless’. Nevertheless, many philosophers have tried to define consciousness with very differing results. Crook (1980) defines consciousness as a self-monitoring facility with a focal and peripheral area, which cannot be accessed through introspection. Humphrey (1983) on the contrary defines consciousness as the set of subjective feelings, which at any time are available to introspection. Chalmers (1996) tries only to characterize consciousness (because it cannot be defined) by describing it as being a subjective feeling of experience: that there is something like to be the being you are, with qualitative, subjective feelings (qualia) about it. These definitions all differ in nature, showing that defining or characterizing consciousness is not an easy task and always from a subjective point of view.

Another controversial topic is what substance consciousness is made of. Incorporated in this issue is the question of the relationship between the mind (including consciousness) and the physical body, the classical mind-body problem. Descartes invented the idea of dualism, in which he separates the body and mind into two different entities (Dicker, 1993; Lindahl, 1997). Therefore the mind is made of a separate substance than the physical body (Blackmore, 2003). Descartes believed that the mind and the body need to interact with each other via the pineal gland (Blackmore, 2003). Another type of dualism is epiphenomenalism (Dualism, 2006). Epiphenomenalism implies that consciousness is produced and influenced by physiological processes, but it has no influence on physical states in return (Bailey, 2006; Blackmore, 2005; Dualism, 2006; Lindahl, 1997). In addition is the view of physicalism, which states that mind and body are made of the same substance and thus mental states are physical states (Functionalism and Physicalism, 2006). Another approach is the idea of functionalism. Functionalism implies that mental states are functional states, that the mind is a functional system (Functionalism and Physicalism, 2006). Though this does not mean that two organisms have to be physical identical to obtain the same function (e.g. consciousness), because functional aspects are said to be multiple realizable (Bailey, 2006), meaning that the same function can arise from different physiological systems (Functionalism and Physicalism, 2006). However, this can be the case if the mind and body are one substance or being different entities. These differing views further illustrate why consciousness research is so complex and pervaded by subjectivity.

In spite of these difficulties, different theories have been developed to try to explain why consciousness has evolved. The possibility of Darwinian evolution of consciousness and alternative theories of the emergence of consciousness are discussed in this paper, as well as limitations of these views. Additionally no discrimination will be made between different kinds of consciousness; when referring to phenomenal consciousness, the subjective experience of consciousness (qualia) is intended.


1.1 Evolutionary theories of consciousness

1.1.1 Introduction of Darwinian evolution

Charles Darwin’s evolutionary theory of natural selection has a great impact on man’s perception of animal (including human) evolution. Natural selection refers to the process by which individuals compete with each other and because each individual is unique in its traits and abilities, some individuals out compete others and produce more offspring (higher fitness) (Darwin, 1859). The traits that promote fitness increase in frequency over generations. These traits are called adaptations (Darwin, 1859). Rossano (2003) states that an adaptation is any anatomical structure, physiological process, behaviour pattern or mental process that increases an individual’s probability of survival and reproduction, relative to other individuals. For the first time a theory could explain coherently why specific traits, shapes and behaviours in animals evolved and why some species went extinct in the course of time. A classic example is the evolution of the giraffe’s long neck, which is belived to have evolved because giraffes with longer necks relative to other giraffes could reach food (leaves) more easily and successfully. Hence, the giraffes with the longer necks had greater chance for survival and reproductive success. Unfortunately Charles Darwin could not explain how these traits got passed on to the next generation. But the discovery of genes brought some insights into this process and refined the evolution theory of natural selection. So that it became clear what mechanisms evolution works on. Natural selection works on an individuals’ phenotype, which are constituted by observable characteristics of an individual (Rossano, 2003a). However, evolution does work on genotypes, which is defined as the genetic makeup of an individual (Rossano, 2003a). Therefore, for a trait to evolve from natural selection the genotype must be expressed in the phenotype, leading to a higher fitness for the individual (Rossano, 2003a).

However, natural selection theory had some limitations, for example it could not explain why some traits did not have any survival value and even seemed to reduce an individual’s survival chance, as for example the long feather tails of peacocks. Darwin himself found a solution to these inconsistencies by formulating the theory of sexual selection in 1871. Which implies that individuals of the same sex compete with each other for access to the opposite sex (Darwin, 1871). Furthermore, sexual selection states that some individuals possess traits that help them to out compete others and that lead to higher reproductive success (Darwin 1871). This theory now can explain why peacocks have their long tail feathers. A peacock with the longest and brightest tail will have more access to females; hence it will produce more offspring. Therefore, not only the survival time promotes the passing on of adaptive traits, but also the resulting greater reproductive success of for example the fittest peacock.

Still, one question remained unanswered. Why do some individuals have more desirable traits than others in the first place? This question is answered by the process of mutation and genetic recombination (in sexual reproducing species). Mutation occurs through copying errors while producing DNA (Rossano, 2003a). This does not imply that every mutation is beneficial. Quite the opposite is the case, as most of the mutations are actually deleterious and decrease the fitness of the organisms (Rossano, 2003a). But some of the mutations result in new genotypes, which increase the individuals’ fitness. Genetic recombination is the recombination of alleles from both parents during meiosis (Rossano, 2003a). Genetic recombination can produce new beneficial gene combinations, because it leads to the development of new genotypes in the offspring and thus new phenotype expressions.

1.1.2 the possibility of Darwinian evolution of consciousness by examining the question of the function of consciousness

Why is the function of consciousness important when discussing the evolution of consciousness? Well, Darwin stated that, to become an adaptation, every trait needs to have a benefit to the fitness of the individual. Therefore, to know if consciousness is an adaptation shaped by natural or sexual selection, one first needs to find the function or functions of consciousness. Several philosophers and psychologists have made an effort to find these functions of consciousness with different results.

Humphrey (1983) believes that consciousness evolved in humans because we need it to be the social creatures we are. Well-developed social structures require introspection to be able to understand, predict and manipulate other members of the group (Humphrey, 1983). A being that is conscious can make inferences about its own states, desires and motivations by using introspection (named ‘inner-eye’ by Humphrey) and can therefore function more successfully in social settings (Humphrey, 1983). Therefore, being conscious gives these individuals the advantage, of displaying superior social behaviour. As a result natural selection could have worked on consciousness to make it an adaptation. The same view is basically held by Jaynes (Crook, 1980, p. 15), who states that an increase in social complexity, with a need for analytical flexibility in interaction with members from other cultures, gave rise to consciousness. Similar to Humphrey and Jaynes, Dawkins (cited in Blackmore, 2003, p.155) speculates that consciousness would evolve ‘when the brain’s simulation of the world becomes so complete that it must include a model of itself’. Therefore, Dawkins believes that consciousness act as a model of ones own brain. The problem here is that most people do not know about a model of their own brain (Blackmore, 2003), as consciousness and introspection do not seem to appear like such a model.

Theories of introspection face a further limitation. They cannot explain the subjective experiences of consciousness (qualia). Horace Barlow (Blackmore, 2003) argues that introspection does not describe representations accurately. He gives the classic example of the redness of red. By introspecting it seems that the perception and experience of red comes first, before it is possible to communicate about it (Blackmore, 2003). However, Barlow argues that the sensation of red is depending on many factors such as experience with red in the past and knowledge of how to communicate about it. Therefore, the sensation of red is a complex product and not a raw experience as introspection makes it seem to be (Blackmore, 2003). Furthermore, Humphrey’s social theory does lead to another implication. If Humphrey’s theory is accurate then consciousness should only concern social interaction aspects and not the wide range of conscious experience humans believe to have (Blackmore, 2003). Moreover, Humphrey’s and Dawkin’s ideas infer what creatures can be conscious and which cannot. Humphreys theory suggests that only highly social creatures and in Dawkins point of view only highly complex ones can be conscious (Blackmore, 2003).

Somewhat in line with Dawkins, Merker (2005) hypothesised that consciousness arose as a solution to the complex problems created by self-motion. This idea is consistent with William James proposal on the origin of consciousness in 1879 (Lindahl, 1997). James states that consciousness emerged to guide a nervous system that had become too complex to regulate itself. Merkers’ elaborated theory, concerns domains like the central control and decision processes between motivational, sensory-spatial and motoric functions (Merker, 2005). The problem Merker (2005) describes is that the organism faces the difficulties of discriminating between self-produced and other-produced information. The complexity of the discrimination problem increases with the sophistication of the motor and sensory systems (Merker, 2005). Simple organisms could solve the difficulty of discriminating between self-produced and other-produced information without consciousness. They can exist with purely excitatory and inhibitory synapses (Merker, 2005), because the discrimination problem they face is not complex enough to have any influence on their reaction time and behaviour. However, consciousness is required in more sophisticated organisms, where excitatory and inhibitory synapses are not able to solve the discrimination problem anymore. Therefore, consciousness could only have evolved in the more complex and sophisticated organisms (Merker, 2005). Thus, consciousness has the advantage that the individual is only aware of the end product of sensory and motor input, after already filtering out the effects of self-motion from the information (Merker, 2005). Hence, the decision process is improved, because the organism is not confused and distracted by trying to solve the problem of self-motion. Moreover, this enhancement does give the individual a reproductive advantage, because it is capable of a faster reaction, which could promote survival and mating partners might prefer those individuals.

Nevertheless, Merkers’ theory does also face some serious problems. Like the introspection theories this theory cannot explain why consciousness has qualia. Removing self-motion information from the information processed, does not account for why consciousness is so subjective. In Merkers explanation this end product could simply be pure perceptions without qualia (a conscious perception or analysis of the input, but without the subjective experience of consciousness). Another weakness is that Merker does not clarify at what point an organism is too complex to resolve the discrimination problem by pure excitatory and inhibitory synapses.


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The origin of consciousness. A review of several major theories and animal consciousness possibility and accessibility
Maastricht University  (Psychology)
8,0 (NL)
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ISBN (Book)
Consciusness, animals, theories, consciousness accessibility
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Stephanie Grehl (Author), 2006, The origin of consciousness. A review of several major theories and animal consciousness possibility and accessibility, Munich, GRIN Verlag,


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