The mind refers to the faculties humans and animals have to perceive, feel, think, remember and want. Consciousness refers to the self-perception and the explicit experiences a person has of the world around them.

There are two mutually exclusive stances in the mind-body debate:

1. Monism
   This stance holds that there is only one kind of thing and this can be subdivided in materialism (1) and idealism (2).
2. Dualism
   This stance holds that there are two kinds of things and this can be subdivided in substance-dualism (1) and property dualism (2).

Property dualism states that there is not an autonomous mental substance but that there are autonomous mental properties. Materialism states that everything is material. Idealism states that everything is mental. Descartes proposed that the body was a machine (1), introduced the mind-body problem (2) and introduced the mind as causal director of the body (3).

There are three major issues with substance-dualism:

1. Interaction problem
   This is the problem of how a non-material entity can influence a material entity.
2. Causal closure problem (e.g. law of conservation of energy)
   This is the problem of how the immaterial mind can be a cause if every physical event has a physical cause.
3. Brain damage (i.e. damage to the material brain influences the mind)
   This is the problem of how a material entity can influence a non-material entity.

Dualism is not used often in scientific circles. According to the materialists, the mind is matter and follows the laws of nature, although tie concept matter is flexible (e.g. fields, states, processes). Materialism has several issues:

1. Problem of qualia (e.g. Nagel)
   This is the problem of whether and how subjective experience can exist if everything is matter.
2. Identity problem (i.e. two different encodings, same experience)
   This is the problem of explaining how two events can be experienced the same if their encodings differ.
3. Problem of simulation (e.g. simulation attempts have failed)
   This is the problem of how the mind can be a sub-product of the brain.
4. Problem of reductionism
   This is the problem of how mental states can be reduced to brain states (i.e. linked to the identity problem and the problem of qualia).

There are different types of materialism:

1. Eliminative materialism
   This type of materialism states that mental states do not exist.
2. Non-eliminative materialism (reductionism)
   This type of materialism states that mental states are rooted in brain states and there is a one-to-one correspondence between brain states and mental states.
3. Non-reductive materialism (no reductionism)
   This type of materialism states that mental states are brain states but there is no one-to-one correspondence between the brain states and the mental states.

The identity theory states that mental states are brain states. This theory requires the answer to what is identical to what. There are several types of identity theory:

1. Type-type identity (allows full reduction psychology to neuroscience)
   This type of identity states that a specific type of mental state is identical to a specific type of brain state.
2. Token-identity theory (reductionism is impossible)
   This type of identity states that a specific type of mental state is identical to a specific type of brain state but differs per person.
3. Token-token identity (reductionism is impossible)
   This type of identity states that one mental state can be realized in multiple ways. There are multiple brain states for each mental state.

Reductionism occurs in several steps:

1. Construct a scientific law in the higher-order science (i.e. the science to be reduced).
2. Establish bridge laws (i.e. one-to-one correspondence relations between terms in the higher-order science and terms in the lower order science).
3. Demonstrate how higher-order law follows from the laws of the reducing science given the bridge laws.

Token-token identity blocks reductionism because it is impossible to construct bridge laws. Multiple realizability refers to the idea that mental states can be physically realized in multiple ways. In multiple realizability, the matter is irrelevant, only the function is relevant (e.g. monetary transactions). Neural plasticity refers to the idea that the same mental state can be realized in different ways.

Functionalism states that mental states are characterized by their function and not by their realization, employing multiple realizability. It states that things (e.g. fear of spiders) are not caused by the brain but realized in the brain. For functionalists, psychological explanations are genuine (1), reductionism is structurally impossible (2) and the identity theory is plausible in the token-token form (3).

Mental states are often defined in terms of content and the content may be encoded in different ways. Belief-desire psychology refers to mental states explaining behaviour (e.g. beliefs translate themselves in desires and behaviour). The individual differences in physical makeup suggest that brains are heterogeneous.

Neuroscience can be relevant without reductionism as the specific mechanisms at the lower level can still be informative for the higher level without reducing that higher level as higher-order properties emerge out of lower order processes in complex systems.

The Turing machine demonstrates that the brain is not essential for thought processes, leading to the question of how unique consciousness is. This philosophical question can be demonstrated by several thought experiments:

Nagel states that it is impossible to learn what it is like to be someone else using objective descriptions. It is only possible to know what it is like to be someone else for you. Searle states that consciousness is an essential biological phenomenon as simulating is not the same as understanding.  Chalmers coined the hard problem of consciousness as it is unclear how physical properties lead to subjective experiences.

The cognitive disclosure hypothesis states that the problem of consciousness might be cognitively too difficult for humans as some cognitive ideas and theories are too difficult for a species (e.g. Pythagoras’ theorem for a dog).

The global workspace model states that the role of consciousness is meant to make information available to the whole brain so that various background processes can align their functioning to what is going on centrally.

The theory of unconscious thought states that it is possible to evaluate information without consciousness and that there are three main differences between conscious and unconscious thought:

• Unconscious thinking is completely determined by the stimuli whereas conscious thinking is not completely determined by the stimuli.
• Unconscious thinking is not able to follow strict rules, whereas conscious thinking can follow strict rules.
• Unconscious thinking has a large capacity, whereas conscious thinking has a low capacity.

Type 1 thinking (i.e. unconscious thought) is an automatic system and involves all type of information processing that does not require focussed attention and that produce an output without any apparent effort or awareness. Type 2 thinking (i.e. conscious thought) is a type of thinking which is serial and conscious.

According to functionalism, teleportation would be possible as long as the input-output relations of a person remain the same (i.e. the function). Multiple realizability implies that it is possible to transfer consciousness from one medium to another medium.

The symbol grounding problem refers to the finding that representations used in computations require a reference to some external reality to get meaning (e.g. understanding a language with only a dictionary is impossible as the words need to be grounded to get meaning).

Embodied cognition is the view that interactions between the human body and the environment form the grounding of human cognition. Embodied information originates in human physiology (1), evolutionary history (2), socio-cultural situatedness (3) and practical activities during reasoning (4).

Free will states that humans can operate autonomously and people are the starting point of behaviour. Determinism states that the physical world fully determines the physical state and does not leave room for free will. For free will to exist, the intention of behaviour needs to precede behaviour (1), the behaviour must not be pre-determined (2) and the intention needs to be the cause of behaviour (3). It is unclear whether intentions are required to make use of language.

Libet demonstrated that the preparation of behaviour in the brain precedes intention, although consciousness and free will may play the role of cancelling behaviour before it is performed, linking to the global workspace model. It is possible that free will is an illusion and that the mental states are caused by the physical state of the brain.

Leibniz believed that the universe could be compared to a living organism in which the building blocks are monads; energy-laden and soul-invested units. There are four types of monads:

1. Simple monads
   These monads form the bodies of all matter and have unconscious and unorganised perception. These monads tend to keep in line with the existing pre-established harmony of the universe.
2. Sentient monads
   These monads are present in all living organisms but not in the inorganic material. It includes the capacity to feel pleasure, pain and voluntary focusing of action.
3. Rational monads
   These monads are the conscious minds of humans and possess the capacity of apperception.
4. Supreme monads
   These monads control and motivate all other monads (e.g. God).

Dawkins states that information units (i.e. memes) reproduce itself according to the principles of evolutionary theory. Marr states that information processing can be studied at the computational level (1), algorithmic level (2) and implementation level (3).