Estrategias para llevar a cabo la conversación

What seems to be behind the arguments from functionalism, however, is the idea that psychology cannot reduce to neuroscience because psychology and neuroscience worry about completely different types of questions. that is, even if bridge principles link psychology to neuroscience, neuroscience could not subsume explanation in psychology for pragmatic reasons (Fodor and Pylyshyn 1988; Pylyshyn 1980, 1984; Putnam 1983). Different levels of analysis in cognitive science attempt to answer fundamentally different sorts of why questions, each with its own contrast class and background context. some questions revolve around the basic capacity of the system under investigation; other questions involve the processes subserving the capacities; and still others relate to the physical mechanisms that underlie the processes subserving the capacities (Marr 1982).

suppose a pedestrian sees an automobile accident at a street corner. this pedestrian whips out her cell phone and pushes the button for nine and then for one. What will she do next? We can be fairly certain that she will push the button for one again. Why? We believe we know what she will do because of our background knowledge regarding cell phones, emergency calls, automobile accidents, and so forth. however, if we focus on the pedestrian’s neurophysiology and resulting muscular contractions, we would not be able to draw this conclusion. that simply is the wrong level of investigation and analysis for our conclusion, for we have no good way to link neural sequences to larger social contexts (in today’s neuroscience anyway). a neural explanation will miss everything that seems to be important in understanding this behavior.

this is an additional problem with the classic formulation of reduction – the notion of explanation it presupposes is much too weak. explanations in science are more than just simple derivations from sets of theories and data. (one difficulty with this simple view of explanation is the problem of irrelevant factors [salmon 1971]. For example,

if we observe salt dissolving in water under a fluorescent light, we do not conclude that the fluorescent light caused the salt to dissolve, even though we could derive the fact that the salt would dissolve from the facts that salt was placed in water and it was placed under a fluorescent light. We would maintain that light is not a relevant factor in salt’s dissolving. It turns out that we can derive explanations that appeal to all sorts of things that are actually irrelevant to the event; nonetheless, we know that explanations should pick out only the factors that are causally relevant in the event to be explained.)

there is no agreement about how to solve this and other problems in philosophical accounts of scientific explanation. there is however a rough consensus that we need a pragmatics of explanation (hempel 1966; Kitcher 1988; Railton 1981; van Fraassen 1980), although whether pragmatics alone can solve the problem of irrelevant factors is doubtful (Kitcher and salmon 1987). In any case, the following at least seems to be clear: some explanations answer questions of the form “Why F?” that are short-hand for the question “Why F and not G, H, or I?” Investigators ask these elliptical questions against a background context of the relevant interested community. For example, a doctor might want to know why george died of a heart attack and not a stroke, while his wife wants to know why george died of a heart attack instead of surviving it. In each case, the interested parties could frame their question as, “Why did george die?,” with the background context implicitly understood by their communities.

the essence of this conception of explanation is that explanations are three-way relations among theories, data, and context. exactly how to specify the relations involved is beyond the scope of the chapter. all we need to know is that whether something is an explanation depends at least upon the speakers, the audience, and circumstances of the inquiry – explanations per se cannot be divorced from the particular community in which they arose.

therefore, if neuroscience is going to reduce psychology, then there have to be neuroscientific equivalents to all relevant psychological statements. that is, if a scien- tific question is formulated and answered in psychological language, there have to be corresponding neurophysiological statements that express all the concepts involved, including those from the background context. to argue that psychology cannot be reduced by neuroscience, philosophers must show either that not all psychological names and predicates have neuroscientific equivalences or that, if there be such equivalences, then they cannot be used to reformulate psychological explanations. With these conceptual tools in hand, we turn once again to the question of whether psychology should reduce to neuroscience.

the difficulty, as I see it, is that linking terms in psychology to those in neuro- science would not thereby explain our psychological generalizations. For each functionally defined psychological term, there are two possible ways a bridge principle could link it to a neuroscientific one. either there is some neurophysiological structure that is identical (or similar enough) across all instances of the psychological term, in which case neuroscience could define the psychological term as the structure itself; or there are no structural similarities, in which case the psychological term could be understood functionally in neuroscience, as discussed above.

assume first that we get an easy link between a neurophysiological structure and a functionally-defined psychological term. Would this link now explain the psycho- logical term? the answer has to be no. Why does the term refer as it does? Because this is a functional term, part of that answer depends upon how its referent is causally connected to other psychologically defined objects or processes. If we knew the structure underlying our cognitive terms down to the most minute detail, it still would not change our psychological explanation of some event, because knowing the structure would not change the relevance of the functional explanation to the query as deter- mined by the background context of cognitive psychology. outlining the structure would only bury the psychological explanation in a mass of irrelevant data. Why did I see the swinging knife as a threat? Knowing the neurophysiological structures that underlie my visual processing is not going to explain why I saw a threat. Knowing the social and cultural significance of a swinging knife, knowing how my beliefs about swinging knives are connected to my other beliefs, is.

now let us suppose instead that we have functionally defined our psychological term in neuroscience by importing the necessary terms and predicates from psychology. Would the links between neuroscience and psychology now explain why I experience the swinging knife as I do? again, the answer must be no. If the statements in neuro- science just are the statements in psychology, then the description of the experiential event must be the same in both fields. Furthermore, because the statements accepted by the two scientific communities concerning the psychological term are ex hypothesis the same, the background context for the term must also be the same. hence, the explanation in neuroscience would be the same as well. the one-step derivation of the psychological from neuroscience would have nothing to add to the psychological explanation because the neuroscientific account would be exactly the same as the psychological.

We are seeing this situation all the time in neuroscience these days in brain imaging experiments. In many instances, cognitive neuroscience has simply imported psychological concepts wholesale into its conceptual framework. as a result, while an imaging study might tell us something about where in the brain a particular process is occurring, it does not say anything about the truth of the psychological claim purportedly under examination.

We have to conclude that traditional reductionistic approaches to understanding the relationship between psychology and neuroscience must fail. It is clear that the answer is more complicated than philosophers originally thought.