section_path: Relation to matter/Mind–body problem
section_name: Mind–body problem
paragraph_text: Mind–body problem
  
  The mind–body problem is the difficulty of providing a general explanation of the relationship between mind and body, for example, of the link between thoughts and brain processes. Despite their different characteristics, mind and body interact with each other, like when a bodily change causes mental discomfort or when a limb moves because of an intention. According to substance dualism, minds or souls exist as distinct substances that have mental states while material things are another type of substance. This view implies that, at least in principle, minds can exist without bodies. Property dualism is another form of dualism that says that mind and matter are not distinct individuals but different properties that apply to the same individual. Monist views, by contrast, state that reality is made up of only one kind. According to idealists, everything is mental. They understand material things as mental constructs, for example, as ideas or perceptions. According to neutral monists, the world is at its most fundamental level neither physical nor mental but neutral. They see physical and mental concepts as convenient but superficial ways to describe reality.
  
  The monist view most influential in contemporary philosophy is physicalism, also referred to as materialism, which states that everything is physical. According to eliminative physicalism, there are no mental phenomena, meaning that things like beliefs and desires do not form part of reality. Reductive physicalists defend a less radical position: they say that mental states exist but can, at least in principle, be completely described by physics without the need for special sciences like psychology. For example, behaviorists aim to analyze mental concepts in terms of observable behavior without resorting to internal mental states. Type identity theory also belongs to reductive physicalism and says that mental states are the same as brain states. While non-reductive physicalists agree that everything is physical, they say that mental concepts describe physical reality on a more abstract level that cannot be achieved by physics. According to functionalism, mental concepts do not describe the internal constitution of physical substances but functional roles within a system. One consequence of this view is that mind does not depend on brains but can also be realized by other systems that implement the corresponding functional roles, possibly also computers.
  
  The hard problem of consciousness is a central aspect of the mind–body problem: it is the challenge of explaining how physical states can give rise to conscious experience. Its main difficulty lies in the subjective and qualitative nature of consciousness, which is unlike typical physical processes. The hard problem of consciousness contrasts with the "easy problems" of explaining how certain aspects of consciousness function, such as perception, memory, or learning.