Now and then authors writing about the mind and its place in nature will make the correct observation that trees and plants have neither nerve systems nor sense organs, whereas vertebrates and invertebrates are equipped with both. The common explanation of this remarkable difference is that plants and trees are stationary but animals move around. The nutrition of plants comes from rain water and the soil in which they grow; wind, insects, or birds help to pollinate other exemplars of the same species; and since they are immobile they cannot escape external dangers such as heavy fires or gusty winds. Therefore, they need no sense organs to take care of themselves. Ecologically it would have been a waste of energy for evolution to have given plants and trees sense organs for no use. In contrast, vertebrates are mobile. As such they need information about their surroundings to survive. The more efficient their sense organs are, the better they are able to move around, gather food, or find a mating partner. Not to mention escaping predators and finding shelter. The brain and the spinal cord have co-evolved with the sense organs. Most philosophers and scientists agree that the main function of the brain is to process information about the environment received by the sense organs and to coordinate this information with bodily behavior. This is the evolutionary purpose of the brain.
But why are we and at least some other vertebrates partially conscious of these information-coordination processes? Does the so-called conscious mind have an additional evolutionary purpose which is not the purpose of the brain alone? A robotic vehicle moving around on Mars is not conscious of the information its sensors received from the surface of Mars other than acting according to the instruction given to it as part of the encoded program. The rover needs no consciousness to avoid rocks, abysses, or steep hills. Though undoubtedly non-conscious, it manages to move around as successfully as a conscious agent, due solely to optical sensors and a computer program by which it avoids physical obstacles. So why have humans evolved such that our bodily activity is correlated with consciousness in contrast to the movement of that vehicle? Answering such a question is an important task for any naturalist. The philosophical challenge is to give an explanation of consciousness in terms of adaptation to the environment, but also, one may argue, to offer an explanation of how brain processes can be associated with mental activities such as perception, imagination, volition, and thinking. In short, what is the mindâs relation to the body? Is it possible to explain mental phenomena merely in virtue of physical ongoing in the brain or do we have to introduce some additional mental properties alongside the physical ones?
Let me begin by stating forthrightly that I make the following assumption: just as the functions of a brain make a significant difference between those organisms that have it from those that do not, it seems likewise plausible to believe that consciousness imparts abilities to an organism that has consciousness which make it different from those that lack it. All naturalists agree that the role of experiences and thoughts is to guide the organismâs physical behavior. The mind is the arbitrator of physical information about the environment and of the organismâs behavioral responses back to the environment. Both mind and the later evolved consciousness add to the agentâs survival faculties. However, not all naturalists agree about the nature of the mind. Some argue that the biological function of the brain explains only why we have a mind, not of what kind of stuff the mind is made or the properties it can be attributed. The objection is that no functional account of the brain can explain the phenomenal aspects of the mind. In my opinion the latter claim is problematic, and in due course I shall argue that the nature of mental states is that they are causal states between the brain and its environment. Minds do not consist of a distinct stuff or of non-physical properties.
If the brain is not just a computer, the rise of consciousness must find its explanation in the way living system are adapted to process information. Indeed, such a conjecture presupposes that consciousness is not functionally identical to a computational program in case consciousness is a natural phenomenon. Non-biological systems like computers need not possess consciousness. The brain is far from being a computer partly due to the fact that it cannot process information nearly as fast as any modern computer. Therefore, nature has compensated the slowness of the brain by adding experiential and conceptual functions to organismsâ cognitive repertoire. Artificial intelligence is one thing, natural intelligence quite another.
1.1 Consciousness and Evolution
The first methodological assumption of this book is that consciousness is the product of biological evolution and that consciousness appeared only after the development of the mind itself. Minds came first, consciousness and self-consciousness much later. I stipulate that mind can be ascribed to any organism having nerve cells. Some organisms have a few hundred of them and therefore have only a very rudimentary mind, whereas others have millions or trillions so their mind is much more advanced. Consequently having a mind comes in degree. The same holds for consciousness. Although many organisms can be said to have a mind, they are not merely for that reason conscious. Before consciousness comes into existence the brain has to reach a high level of complexity. In a changing world, the brainsâ function is to coordinate an organismâs behavior with respect to various inputs from the environment, but only those organisms that have consciousness can be aware of their sensory inputs as well as imagine what to do given these sensory inputs.
Ever since Descartes philosophers have been used to thinking of the problem of consciousness as one about the relationship between the mind and the body, which in itself is so mysterious that many correctly believe that we cannot grasp this relation just by knowing the mind and knowing the body. By introspection the mind appears to have characteristics so very different from those of the brain that their relation seems unintelligible for any human beings. The relationship may therefore consist of something extra, which philosophers have been unsuccessful in trying to explain. Perhaps this lack of success results from the mischaracterization of the problem in terms of an ontology that was originally developed from within the Cartesian epistemic perspective.
The philosophical theory of the mind took a different route than the one followed by the natural sciences. This was because Descartes saw the subjectivity of mental states as the starting point for any possible epistemology, and because Kant sharply distinguished between human freedom and natureâs necessity. Descartes did not make a distinction between mind and consciousness. In this perspective it was the Cartesian emphasis on consciousness and the German idealistsâ focus on mind over matter that climaxed in Husserlâs concept of âpure phenomenonâ; i.e. the view of bracketing the natural attitude towards an objective world and seeing consciousness as it immediately appears to itself. The Cartesian approach involves the first-person perspective of perceptions and mental representation. Only the conscious subject can know his or her own perceptions, and all that the subject directly knows are its perceptions. The basic idea behind this approach is that sense impressions are mental representations of what causes them and that objects represented do not have objectively the same properties as the mental representations. The mind cannot get an independent view of itself, because consciousness is just as it is immediately grasped by the subject.
My opinion is that the first-person standpoint is the wrong road to follow, because it sticks to a mentalist characterization of the mind. The right move is to look for a detached, or as I would say, a naturalist, notion of the mind, which considers all mental activities, like physical activities, as a result of complex relations between the organism and its environment. The goal is to show that consciousness, in general, is not a result of a particular subjective nature of our own cognitive processes. There must, I think, be a reason why consciousness is part of nature. The mind has presumably given animals possessing consciousness an advantage in the struggle for survival. In such an ontological perspective sensory experiences are a part of the general adaptation of the information processing capacity to match a slow bodily reaction time. This yields a naturalist approach to the nature of consciousness, and takes us to the third person perspective on perception and mental representation .
Apropos mental representation . Kant spoke of the Understanding (mind) as forming a Vorstellung of the object. That word should have been rendered a âpresentationâ (of the mind to itself) of the object; it was how the object is presented to consciousness. Unfortunately, it got translated into English as ârepresentation.â But there is a big difference. A âpresentation â is in some sense the real thing; a representation is a copy (often a poor one or an arbitrary stand-in for the real thing). I might say âI present myself to the world as a philosopher.â That means I really am a philosopher. If I say âI represent a philosopher,â it means that I am claiming to be a philosopher, or I am standing for a philosopher, but I may not really be one, or perhaps I am a rather poor example of one. People do not ordinarily confuse real things with copies of things, but sometimes they are fooled. Nevertheless, the mind came to be seen as a picturing machine, a kind of photography device, the mirror of Nature. Since we have access to only the picture, naturally this led to the crisis of being trapped in Descartesâ subjective prison. This led, in turn, to the pragmatistsâ (and the phenomenologistsâ, too) attempt to break out of jail and boldly claim that we experience objects not our mental pictures of objects. This mode of thinking is inherently hostile to representationalism. So later I shall distinguish between âpresentationâ and ârepresentationâ, saying that some mental states, like sensory impressions and perceptual experiences, are to be considered as presentations because their epistemic content is not intentionally determined by the observerâs act of will, whereas images, thoughts, pictures, and words are representations because their epistemic content is intentionally determined by how they are used or are put to use.
Science is, indeed, committed to promise an explanation of the first person perspective and how it comes about. This could be done by reference to the conscious sensory experience as a completely intersubjective feature of particular organisms that has to be understood like any other âintersubjectiveâ features of their cognitive abilities. Sensory experiences are obviously species-specific. The world is experienced differently for a bat and a human being; nevertheless, it is the same world experienced by both. Science is, of course, obliged to explain why information about external and internal events has a sensory appearance. Why phenomenal qualities appear in relation to sensation must have a purely Darwinian answer. Such a naturalist attitude should also provide an answer to why different organisms have different sensory experiences, and why robots have no sensory experience at all.
Human evolution and natural selection do not by themselves tell us how we should understand the nature of mind; however, these conceptions point our search in the right direction. The traditional reductive physicalist approaches to the question of the ontological status of the mind reject dualism and defend materialism either in the form of behaviorism, eliminativism, or some version of identity theory. But, in my opinion, both idealism and materialism are insufficient frameworks of understanding the mind, although they basically get rid of Descartesâ immaterial substance and solve the interaction problem. Both theories suffer from their inability to explain the nature of the mind in an evolutionary setting. Most philosophers and scientists would agree that the so-called conscious mind is a result of biological evolution, but the great challenge is to explain consciousness so its defining characteristics are something which could be selected by Darwinian mechanisms and still pave the way for presentation, meaning, norms, and values.
It seems impossible, as eliminative forms of materialism attempt to show, that our talk about consciousness is something which can be removed because consciousness is not ultimately real. Consciousness is real to us; it makes a difference for us. This is what matters. More to the point is the Cartesian point: each subject is directly aware of his consciousness; it is hard to see how I could be mistaken in believing that I am conscious. My own consciousness is not constructed or inferred from something else. Much of our understanding of social and cultural reality is constructed by the social community in which we live and projected by the mind onto the perceptual world as being meaningful. We cannot explain these kinds of phenomena just by talking about brain states alone.
Nor can we explain our scientific grasp of the natural world without reference to the world as we experience it. We can never get to understand the world as it is in itself, we can only describe it as we understand it in connection with our sensory experience. For this reason it is preferable to express epistemological criteria in terms of âintersubjectivityâ rather than âobjectivity.â Sensory information is the source of our conscious perspective on the world, and based on some particular experience it is our ability to understand this experience that determines whether we find a particular description meaningful and appropriate.
The identity theory takes mental states to be strictly identical to brain states. It sees these brain states as capable of forming representations, but it is still unable to give an account of why neural properties form mental representations , or indeed even if neural properties do represent, much less how do they do it without being similar, at least in some respects, to what it is that they allegedly represent. The assumption behind the classical identity is that mental properties are one and the same as neural properties that are all intrinsic to the brain. Consciousness is nothing but brainâs processes, which implies that mental qualities are not different from material properties belonging to the brain itself. However, this is exactly where the problem of the theory is located. The so-called conscious mind cannot be reduced to what goes on physically in the nervous system. The old identity theory failed, not because of multiple realizations, as we shall see, but because it took for granted that the explanation of consciousness could be formulated solely in terms of what happens in a single physical organ, the brain. The proponents of the theory didnât realize that whatever the nature of the intrinsic properties of the brain might be, we cannot refer merely to these properties to provide a scientific account of the content of perceptions, thoughts, and imaginations.
1.2 Non-reductive Naturalism
Old materialist theories ar...