The human brain

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Today it is common to compare the human brain to a computer, and a human mind to a program running on a computer. Once seen as just a poetic metaphor, this viewpoint is now supported by most philosophers of human consciousness and most researchers in Machine Intelligence. If we take this view literally, then as we can ask how many gigabytes of RAM a PC has we should be able to ask how many gigabytes of memory the human brain has.

Machine intelligence researchers have used a digital computer as a model of the human mind in two ways. Most obviously, the computer has been used as a tool, on which simulations of thinking-as-programs are developed and tested. Less obvious, but of great significance, is the use of the computer as a conceptual model of the human mind. This essay traces the sources of this machine-modeled conception of cognition in a great variety of social institutions and everyday experiences, treating them as "cultural models" which have contributed to the naturalness of the mind-as-machine paradigm for many people, the roots of these models antedate the actual and cognitive landscape of modernity. The essay concludes with a consideration of some of the cognitive consequences of this extension of machine logic into modern life, and proposes an important distinction between information processing models of thought and meaning-making in how human cognition is conceptualized. (Tugui 2006)

Kn?wledge i? defined by the ?xf?rd Engli?h Di?ti?n?ry ?? (i) ex?erti?e, ?nd ?kill? ??quired by ? ?er??n thr?ugh ex?erien?e ?r edu??ti?n; the the?reti??l ?r ?r??ti??l under?t?nding ?f ? ?ubje?t, (ii) wh?t i? kn?wn in ? ??rti?ul?r field ?r in t?t?l; f??t? ?nd inf?rm?ti?n ?r (iii) ?w?rene?? ?r f?mili?rity g?ined by ex?erien?e ?f ? f??t ?r ?itu?ti?n. Philosophical debates in general start with Plato's formulation of knowledge as "justified true belief". There is however no sigle agreed definition of knowledge presently, nor any prospect of one, and there remain numerous competing theories.

Knowlegde asquisition involves complex cognite processes: perception, learning, communication, association and reasoning. The term knowledge is also used to mean the confident understanding of a subject with the ability to use it for a specific purpose if appropriate. (Bergeron, 20008) Belief is the psycological state in which an individual holds a proposition or premise to be true.

Epistimology is the phisolophical study of knowledge and belief. The primary problem in epistimology is to understandexactly what is needed in order for us to have knowledge. In a notion derived from Plato's dialogue Theaetetus, philosophy has traditionally defined knowledge as justified true belief. The relationship between belief and knowledge is that a belief is knowledge if the belief is true and if the believer has a justification (reasonable and nessesary evidence/guidance) for believing it is true.

A false belief is not considered to be knowledge, even if it is sincere. A sincere believer in the flat earch theory does not know that the Earth is flat. Similarly, a truth that nobody belives is not knowledge, because in order to be knowledge, there must be some person who knows it.

Basic psychology and related disciplives have traditionally treated belief as if it were the simplest form of mental representation and therefore one of the building blocks of concious thought. Philosophers have tended to be more abstract in their analysis and much of the work examining the viability of the belief concept stems from philosophical analysis. (Denning & Metcalfe 2007)

The concept of belief presumes a subject (the believer) and an object of belief (the proposition). So, like other propositional attitudes, belief implies the existence of mental states and intentionality, both of which are hotly debated topics in the philosophy of mind whose foundations and relation to brain states are still controversial.

Beliefs are sometimes divided into core beliefs (those which you may be actively thinking about) and dispositional belifs (those which you may ascribe to but have never previously thought about). For example, if asked 'Do you believe tigers wear pink pijamas?' a person might answer that they do not, despite the fact they may never have thought about this situation before.

That a belief is a mental state has been seen, by some, as contentious. While some philosophesrs have argued that beliefs are represented in the mind as sentence-like sonstructs others have gone as far as arguing that there is no consistent or coherent mental representation that underlies our common use of the belief concept and that it is therefore obsolete and should be rejected

This has important implications for understanding the neurophyshology and neuroscience of belief. If the concept of belief is incoherent or ultimately indefensible then any attempt to find the underlying neural processes which support it will fail. If the concept of belief does turn out to be useful, the this goal should (in princible) be achievable. Philosopher Lynne Rudder Baker has outlined four main contempory approaches to belief in her controversial book Saving Belief

- Our common-sense understanding of belief is correct - Sometimes called the 'mental sentence theory', in this conseption, beliefs exist as coherent entities and the way we talk about them in everyday life is a valid basis for scientific endeavour. Jerry Fodor is one of the principal defenders of this point of view.

- Our common-sense understanding of belief may not be correct, but it is close enough to make some useful predictions - This view argues that we will eventually reject the idea of belief as we use it now, but that there may be a correlation between what we take to be belief when someone says 'I believe that snow is white' and however a future theory of psycology will explain this behaviour. Most notably philosopher Stephen Stich has argued for this particular understanding of belief.

- Our common-sense understanding of belief in entirely wrong and will be completely superseded by a radically different theory which will have no use for the concept of belief as we know it - Known as eliminativism, this view, (most notably proposed by Paul and Patricia Churchland), argues that the concept of belief is like obsolete theories of times past such as the four humours theory about medicine, or the phlogiston theory of combustion. In these cases science hasn't provided us with a more detailed account of these theories, but completely rejected them as valid scientific concepts to be replaced by entirely different accounts. The churchlands argue that our common-sence concept of brain is similar, in that as we discover more about neuroscience and the brain, the inevitable conclusion will be to reject the belief hypothesis in its entirety.

- Our common-sense understanding of belief is entirely wrong, however treating people, animals and even computers as if they had beliefs, is often a succesful srtategy - The major proponents of this view, Daniel Dennett and Lynne Rudder Baker, are both eliminativists in that they believe that beliefs are not a scientifically valid concept, but they don't go as far as rejecting the concept of belief as predictive device. Dennett gives the example of playing a computer at chess. While a few people would agree that the computer help beliefs, treating the computer as if it did (e.g. that the computer believes that taken the opposition's queen will give it a considerable advantage) is likely to be a succesful and predictive strategy. In this understanding of belief, named by Dennett the intentional stance belief based explanations of mind and behaviour are at a different level of explanation and are not reducible to those based on fundamental neuroscience although both may be explanatory at their own level. (Mesarovic & Pestel 2008)

Reality Vs Model of Reality

Reality, in everyday usage, means "the state of things as they actually exist." In one sense it is what is real; in its widest sense the term reality includes everything that is, whether or not it is observable or comprehensible. Reality in this sense includes being and sometimes is considered to include nothingness, where existence is often restricted to being (compare with nature).

A common colloquial usage would have 'reality' mean 'perceptions, belief and attitudes toward reality,' as in 'My reality is not your reality.'