Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
Intentionality (the ability of a system to refer to something outside it) is at the center of the philosophical debate on meaning.
Willard Quine’s “instrumentalist theory” rejected intentionality altogether, considering it merely a linguistic trick. Quine thus denied psychology (that deals with desires, beliefs and hopes and so forth) the status of science.
Daniel Dennett reached a similar conclusion: the intentional stance is simply one of the possible ones, and it is just that, a stance. It is useful to attribute intentional states to other humans, and maybe even to non-human systems. Intentionality is only a feature of our language, a tool. The mind is not intentional because it does not exist, it is only a term in the vocabulary of folk psychology. The brain is not intentional because its states do not refer to anything: they simply are what they are, just like in any physical system.
Jerry Fodor’s representational theory, instead, posits that the brain literally contains the intentional state that we ascribe to the mind. For Fodor, the vocabulary of folk psychology “is” a scientific language: it describes facts that are really happening in the brain, not just linguistic tools.
The US philosopher Ruth Millikan argued that intentionality is an objective, natural, biological feature of humans, that evolved over millions of years just like any other organ or limb of the human body. Intentionality is no more than the biology of belief, desire, hope and intention, which must be treated like any other biological object. Propositional attitudes (beliefs, hopes, desires, intentions) are biological devices, designed by evolution to have some effects on us. That effect is its content. Thus the effect has been determined by evolution. This strategy of treating intentionality as a biological feature can be extended to treating meaning as a biological phenomenon (“biosemantics”), because each sentence can be viewed as having a biological function (typically, helping us live in the world). “Sentences are basic intentional items”. Intentionality is grounded in the relationship with the environment, a relationship determined by evolution. A mental content is the effect of a biological system designed by evolution to have that effect. Presumably, Millikan believes that desires and beliefs are physiological features of the brain, because they have evolved from generation to generation just like any other bodily organ has. On the other hand, the contents of these beliefs and desires are located outside the brain, and can be understood only by understanding their biological function, i.e. their evolutionary history. A belief is similar to the dance of a bee, a biological feature designed by evolution that refers to an object outside the head of the bee.
The “externalist theory” of the British philosopher Colin McGinn’s is an extension of Millikan’s teleological theory. The mental content of humans is external to their minds for the simple reason that it was set by evolution and it refers to the environment. The cognitive life of humans has been shaped by evolution to cope with an external object, the environment. Beliefs and desires are brain states whose content is a relation to the external world.
The information-processing theory of the US philosopher Fred Dretske assumes that cognitive life consists in transforming analogue information (that comes from the sensory system) into digital information (that can become the processed as knowledge). For example, a smell per se is only a set of sensory data. Once it is analyzed and turned into the information that it corresponds to, the smell of a particular flower, we “know” a fact about the world. This transformation from analogue to digital is what creates a “belief”. A belief is therefore a neural structure. This is what the system “believes”. The content of that belief is thus defined by its informational origin and not by its behavioral effect. A concept is the link between the information origin and the behavioral effect. The semantic content becomes a cognitive content when it is transformed from a representational unit to a functional unit.
In the functionalist theory of the British philosopher Brian Loar beliefs and desires are real physical states with real causal powers, but they are wholly defined by and within the overall network of beliefs an desires. A belief is defined by its functional role within the network of the person’s beliefs. In a sense, the mind “is” the network of prepositional attitudes.
The US philosopher John Searle thinks that intentionality can only be relative to a contextual "network" of other intentional states and to a "background" of pre-intentional stances. The background is necessary for the network to function. In other words, in order to perform a mental act, one must have a network of mental acts and they must be grounded in the real world. For example, I can "desire to see a film" only if I believe that the film exists and is showing. Thus the "network". And i can go and see the film only if I know how to drive the car and how to find the address. Thus the "background".
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