. Inputs are passed by the sensory organs to the
pineal gland, and from there to the immaterial
spirit. The mind–body problem concerns the explanation of the relationship that exists between
minds, or
mental processes, and bodily states or processes. For example, someone's desire for a slice of pizza will tend to cause that person to move his or her body in a specific manner and direction to obtain what he or she wants. The question, then, is how it can be possible for conscious experiences to arise out of a lump of gray matter endowed with nothing but electrochemical properties. leads to the erroneous conclusion that
Samkhya supports
substance dualism. Yet both mind and body are equally non-conscious (jaDaa) in
Samkhya and, while they are different developments of
prakriti, they are both made up of
gunas. In Western philosophy, the earliest discussions of dualist ideas are in the writings of
Plato, who suggested that humans'
intelligence (a faculty of the mind or soul) could not be identified with, or explained in terms of, their physical body. However, the best-known version of dualism is due to
René Descartes (1641), and holds that the mind is a non-extended, non-physical substance, a "
res cogitans". The most frequently used argument in favor of dualism appeals to the common-sense intuition that conscious experience is distinct from inanimate matter. If asked what the mind is, the average person would usually respond by identifying it with their
self, their personality, their
soul, or another related entity. They would almost certainly deny that the mind simply is the brain, or vice versa, finding the idea that there is just one
ontological entity at play to be too mechanistic or unintelligible. Mental events have a subjective quality, whereas physical events do not. So, for example, one can reasonably ask what a burnt finger feels like, or what a blue sky looks like, or what nice music sounds like to a person. But it is meaningless, or at least odd, to ask what a surge in the uptake of
glutamate in the dorsolateral portion of the
prefrontal cortex feels like. A related thought experiment is the
Inverted Spectrum Hypothesis (ISH). Which explores the idea of people experiencing colors differently. The ISH suggests that people could have an inverted view of colors. For instance, what one person sees as red, another person might see the opposite on the color wheel, which would be green. However, both people have learned to assign the color that they experience differently to the one term.The idea can be traced back to John Locke, found in his book
Essay Concerning Human Understanding published in 1690. Philosophers of mind call the subjective aspects of mental events "
qualia" or "raw feels". If consciousness (the mind) can exist independently of physical reality (the brain), one must explain how physical memories are created concerning consciousness. Dualism must therefore explain how consciousness affects physical reality. One possible explanation is that of a miracle, proposed by
Arnold Geulincx and
Nicolas Malebranche, where all mind–body interactions require the direct intervention of God. Another argument that has been proposed by
C. S. Lewis is the
Argument from Reason: if, as monism implies, all of our thoughts are the effects of physical causes, then we have no reason for assuming that they are also the
consequent of a reasonable ground. Knowledge, however, is apprehended by reasoning from ground to consequent. Therefore, if monism is correct, there would be no way of knowing this—or anything else—we could not even suppose it, except by a fluke. The
zombie argument is based on a
thought experiment proposed by Todd Moody, and developed by
David Chalmers in his book
The Conscious Mind. The basic idea is that one can imagine one's body, and therefore conceive the existence of one's body, without any conscious states being associated with this body. Chalmers' argument is that it seems possible that such a being could exist because all that is needed is that all and only the things that the physical sciences describe about a zombie must be true of it. Since none of the concepts involved in these sciences make reference to consciousness or other mental phenomena, and any physical entity can be by definition described scientifically via
physics, the move from conceivability to possibility is not such a large one. Others such as Dennett have
argued that the notion of a philosophical zombie is an incoherent, or unlikely, concept. It has been argued under physicalism that one must either believe that anyone including oneself might be a zombie, or that no one can be a zombie—following from the assertion that one's own conviction about being (or not being) a zombie is a product of the physical world and is therefore no different from anyone else's. This argument has been expressed by Dennett who argues that "Zombies think they are conscious, think they have qualia, think they suffer pains—they are just 'wrong' (according to this lamentable tradition) in ways that neither they nor we could ever discover!"
Christian List argues that the existence of first-person perspectives is evidence against physicalist views of consciousness. According to List, first-personal phenomenal facts cannot supervene on third-person physical facts. However, List argues that this also refutes versions of dualism that have purely third-personal metaphysics. List has proposed a model he calls the "many-worlds theory of consciousness" in order to reconcile the subjective nature of consciousness without lapsing into solipsism.
Interactionist dualism by
Frans Hals (1648) Interactionist dualism, or simply
interactionism, is the particular form of dualism first espoused by Descartes in the
Meditations. It is the view that mental states, such as beliefs and desires, causally interact with physical states. For example,
Joseph Agassi suggests that several scientific discoveries made since the early 20th century have undermined the idea of privileged access to one's own ideas.
Freud claimed that a psychologically-trained observer can understand a person's unconscious motivations better than the person himself does.
Duhem has shown that a philosopher of science can know a person's methods of discovery better than that person herself does, while
Malinowski has shown that an anthropologist can know a person's customs and habits better than the person whose customs and habits they are. He also asserts that modern psychological experiments that cause people to see things that are not there provide grounds for rejecting Descartes' argument, because scientists can describe a person's perceptions better than the person themself can.
Other forms of dualism Psychophysical parallelism Psychophysical parallelism, or simply
parallelism, is the view that mind and body, while having distinct ontological statuses, do not causally influence one another. Instead, they run along parallel paths (mind events causally interact with mind events and brain events causally interact with brain events) and only seem to influence each other. This view was most prominently defended by
Gottfried Leibniz. Although Leibniz was an ontological monist who believed that only one type of substance, the
monad, exists in the universe, and that everything is reducible to it, he nonetheless maintained that there was an important distinction between "the mental" and "the physical" in terms of causation. He held that God had arranged things in advance so that minds and bodies would be in harmony with each other. This is known as the doctrine of
pre-established harmony.
Occasionalism Occasionalism is the view espoused by
Nicholas Malebranche as well as Islamic philosophers such as
Abu Hamid Muhammad ibn Muhammad al-Ghazali that asserts all supposedly causal relations between physical events, or between physical and mental events, are not really causal at all. While body and mind are different substances, causes (whether mental or physical) are related to their effects by an act of God's intervention on each specific occasion.
Property dualism Property dualism is the view that the world is constituted of one kind of
substance – the physical kind – and there exist two distinct kinds of properties:
physical properties and
mental properties. It is the view that non-physical, mental properties (such as beliefs, desires and emotions) inhere in some physical bodies (at least, brains). Sub-varieties of property dualism include: •
Emergent materialism asserts that when matter is organized in the appropriate way (i.e., in the way that living human bodies are organized), mental properties emerge in a way not fully accountable for by physical laws. but it was already suggested in the 19th century by
William James. •
Epiphenomenalism is a doctrine first formulated by
Thomas Henry Huxley. It consists of the view that mental phenomena are causally ineffectual, where one or more mental states do not have any influence on physical states or mental phenomena are the effects, but not the causes, of physical phenomena. Physical events can cause other physical and mental events, but mental events cannot cause anything since they are just causally inert by-products (i.e., epiphenomena) of the physical world. •
Non-reductive physicalism is the view that mental properties form a separate ontological class to physical properties: mental states (such as qualia) are not reducible to physical states. The ontological stance towards qualia in the case of non-reductive physicalism does not imply that qualia are causally inert; this is what distinguishes it from epiphenomenalism. •
Panpsychism is the view that all matter has a mental aspect, or, alternatively, all objects have a unified center of experience or point of view. Superficially, it seems to be a form of property dualism, since it regards everything as having both mental and physical properties. However, some panpsychists say that mechanical behaviour is derived from the primitive mentality of atoms and molecules—as are sophisticated mentality and organic behaviour, the difference being attributed to the presence or absence of
complex structure in a compound object. So long as the
reduction of non-mental properties to mental ones is in place, panpsychism is not a (strong) form of property dualism; otherwise it is.
Dual aspect theory Dual aspect theory or dual-aspect monism is the view that the
mental and the
physical are two aspects of, or perspectives on, the same substance. (Thus it is a mixed position, which is monistic in some respects). In modern philosophical writings, the theory's relationship to
neutral monism has become somewhat ill-defined, but one proffered distinction says that whereas neutral monism allows the context of a given group of neutral elements and the relationships into which they enter to determine whether the group can be thought of as mental, physical, both, or neither, dual-aspect theory suggests that the mental and the physical are manifestations (or aspects) of some underlying substance, entity or process that is itself neither mental nor physical as normally understood. Various formulations of dual-aspect monism also require the mental and the physical to be complementary, mutually irreducible and perhaps inseparable (though distinct).
Experiential dualism This is a philosophy of mind that regards the degrees of freedom between mental and physical well-being as not synonymous thus implying an experiential dualism between body and mind. An example of these disparate degrees of freedom is given by
Allan Wallace who notes that it is "experientially apparent that one may be physically uncomfortable—for instance, while engaging in a strenuous physical workout—while mentally cheerful; conversely, one may be mentally distraught while experiencing physical comfort". Experiential dualism notes that our subjective experience of merely seeing something in the physical world seems qualitatively different from mental processes like grief that comes from losing a loved one. This philosophy is a proponent of causal dualism, which is defined as the dual ability for mental states and physical states to affect one another. Mental states can cause changes in physical states and vice versa. However, unlike cartesian dualism or some other systems, experiential dualism does not posit two fundamental substances in reality: mind and matter. Rather, experiential dualism is to be understood as a conceptual framework that gives credence to the qualitative difference between the experience of mental and physical states. Experiential dualism is accepted as the conceptual framework of
Madhyamaka Buddhism. Madhayamaka Buddhism goes further, finding fault with the monist view of physicalist philosophies of mind as well in that these generally posit matter and energy as the fundamental substance of reality. Nonetheless, this does not imply that the cartesian dualist view is correct, rather Madhyamaka regards as error any affirming view of a fundamental substance to reality.In denying the independent self-existence of all the phenomena that make up the world of our experience, the Madhyamaka view departs from both the substance dualism of Descartes and the substance monism—namely, physicalism—that is characteristic of modern science. The physicalism propounded by many contemporary scientists seems to assert that the real world is composed of physical things-in-themselves, while all mental phenomena are regarded as mere appearances, devoid of any reality in and of themselves. Much is made of this difference between appearances and reality. Today, the most common forms of monism in Western philosophy are
physicalist. However, a variety of formulations (see below) are possible. Another form of monism,
idealism, states that the only existing substance is mental. Although pure idealism, such as that of
George Berkeley, is uncommon in contemporary Western philosophy, a more sophisticated variant called
panpsychism, according to which mental experience and properties may be at the foundation of physical experience and properties, has been espoused by some philosophers such as
Alfred North Whitehead and
David Ray Griffin. A third possibility is to accept the existence of a basic substance that is neither physical nor mental. The mental and physical would then both be properties of this neutral substance. Such a position was adopted by Baruch Spinoza in the 19th century. This
neutral monism, as it is called, resembles property dualism.
Physicalistic monisms Behaviorism Behaviorism dominated philosophy of mind for much of the 20th century, especially the first half. Parallel to these developments in psychology, a philosophical behaviorism (sometimes called logical behaviorism) was developed. Philosophical behaviorism has fallen out of favor since the latter half of the 20th century, coinciding with the rise of
cognitivism. as a direct reaction to the failure of behaviorism. These philosophers reasoned that, if mental states are something material, but not behavioral, then mental states are probably identical to internal states of the brain. In very simplified terms: a mental state
M is nothing other than brain state
B. The mental state "desire for a cup of coffee" would thus be nothing more than the "firing of certain neurons in certain brain regions". Anomalous monism (see below) and most other non-reductive physicalisms are token-identity theories. Despite these problems, there is a renewed interest in the type identity theory today, primarily due to the influence of
Jaegwon Kim. At about the same time or slightly after,
D.M. Armstrong and
David Kellogg Lewis formulated a version of functionalism that analyzed the mental concepts of folk psychology in terms of functional roles. Finally,
Wittgenstein's idea of meaning as use led to a version of functionalism as a theory of meaning, further developed by
Wilfrid Sellars and
Gilbert Harman. Another one,
psychofunctionalism, is an approach adopted by the
naturalistic philosophy of mind associated with Jerry Fodor and
Zenon Pylyshyn. Mental states are characterized by their causal relations with other mental states and with sensory inputs and behavioral outputs. Functionalism abstracts away from the details of the physical implementation of a mental state by characterizing it in terms of non-mental functional properties. For example, a kidney is characterized scientifically by its functional role in filtering blood and maintaining certain chemical balances. Davidson uses the thesis of
supervenience: mental states supervene on physical states, but are not reducible to them. "Supervenience" therefore describes a functional dependence: there can be no change in the mental without some change in the physical–causal reducibility between the mental and physical without ontological reducibility.
Weak emergentism Weak emergentism is a form of "non-reductive physicalism" that involves a layered view of nature, with the layers arranged in terms of increasing complexity and each corresponding to its own special science. Some philosophers like
C. D. Broad hold that emergent properties causally interact with more fundamental levels, while others maintain that higher-order properties simply supervene over lower levels without direct causal interaction. The latter group therefore holds a less strict, or "weaker", definition of emergentism, which can be rigorously stated as follows: a property P of composite object O is emergent if it is metaphysically impossible for another object to lack property P if that object is composed of parts with intrinsic properties identical to those in O and has those parts in an identical configuration. Sometimes emergentists use the example of water having a new property when Hydrogen H and Oxygen O combine to form H2O (water). In this example, there "emerges" a new property of a transparent liquid that would not have been predicted by understanding hydrogen and oxygen as gases. This is analogous to physical properties of the brain giving rise to a mental state. Emergentists try to solve the notorious mind–body gap this way. One problem for emergentism is the idea of
causal closure in the world that does not allow for a mind-to-body causation.
Eliminative materialism If one is a materialist and believes that all aspects of our common-sense psychology will find reduction to a mature
cognitive neuroscience, and that non-reductive materialism is mistaken, then one can adopt a final, more radical position: eliminative materialism. There are several varieties of eliminative materialism, but all maintain that our common-sense "
folk psychology" badly misrepresents the nature of some aspect of cognition. Eliminativists such as
Patricia and
Paul Churchland argue that while folk psychology treats cognition as fundamentally sentence-like, the non-linguistic vector/matrix model of neural network theory or
connectionism will prove to be a much more accurate account of how the brain works.
Mysterianism Some philosophers take an epistemic approach and argue that the mind–body problem is currently unsolvable, and perhaps will always remain unsolvable to human beings. This is usually termed
New mysterianism.
Colin McGinn holds that human beings are
cognitively closed in regards to their own minds. According to McGinn human minds lack the concept-forming procedures to fully grasp how mental properties such as
consciousness arise from their causal basis. An example would be how an elephant is cognitively closed in regards to particle physics. A more moderate conception has been expounded by
Thomas Nagel, which holds that the mind–body problem is currently unsolvable at the present stage of scientific development and that it might take a future scientific
paradigm shift or revolution to bridge the
explanatory gap. Nagel posits that in the future a sort of "objective
phenomenology" might be able to bridge the gap between subjective conscious experience and its physical basis.
Linguistic criticism of the mind–body problem Each attempt to answer the mind–body problem encounters substantial problems. Some philosophers argue that this is because there is an underlying conceptual confusion. These philosophers, such as
Ludwig Wittgenstein and his followers in the tradition of linguistic criticism, therefore reject the problem as illusory. They argue that it is an error to ask how mental and biological states fit together. Rather it should simply be accepted that human experience can be described in different ways—for instance, in a mental and in a biological vocabulary. Illusory problems arise if one tries to describe the one in terms of the other's vocabulary or if the mental vocabulary is used in the wrong contexts.
Naturalism and its problems The thesis of physicalism is that the mind is part of the material (or physical) world. Such a position faces the problem that the mind has certain properties that no other material thing seems to possess. Physicalism must therefore explain how it is possible that these properties can nonetheless emerge from a material thing. The project of providing such an explanation is often referred to as the "
naturalization of the mental". This problem of explaining introspective first-person aspects of mental states and consciousness in general in terms of third-person quantitative neuroscience is called the
explanatory gap. There are several different views of the nature of this gap among contemporary philosophers of mind.
David Chalmers and the early
Frank Jackson interpret the gap as
ontological in nature; that is, they maintain that qualia can never be explained by science because
physicalism is false. There are two separate categories involved and one cannot be reduced to the other. An alternative view is taken by philosophers such as
Thomas Nagel and
Colin McGinn. According to them, the gap is
epistemological in nature. For Nagel, science is not yet able to explain subjective experience because it has not yet arrived at the level or kind of knowledge that is required. We are not even able to formulate the problem coherently. Other philosophers liquidate the gap as purely a semantic problem. This semantic problem, of course, led to the famous "
Qualia Question", which is:
Does Red cause Redness?
Intentionality —one of the most influential philosophers of mind, proponent of
biological naturalism (Berkeley 2002)
Intentionality is the capacity of mental states to be directed towards (
about) or be in relation with something in the external world. It would not make any sense to say that a natural process is true or false. But mental ideas or judgments are true or false, so how then can mental states (ideas or judgments) be natural processes? The possibility of assigning semantic value to ideas must mean that such ideas are about facts. Thus, for example, the idea that
Herodotus was a historian refers to Herodotus and to the fact that he was a historian. If the fact is true, then the idea is true; otherwise, it is false. But where does this relation come from? In the brain, there are only electrochemical processes and these seem not to have anything to do with Herodotus. ==Philosophy of perception==