A fuzzy limbic system.

Some years ago, while he was President of Harvard, James B. Conant ~ pointed out that scientific theories are not overthrown by the accumulation of observations inconsistent with them, but are only abandoned by displacement by theories that encompass more data and explain known 'exceptions' to the general rules of the existing theory. In short, established concepts and theories disappear only when replaced by more useful and 'fruitful' ones. And so it is with the concept of the 'Limbic System'. As a conceptual term it will survive in the face of all criticisms until a more comprehensive, and fruitful, or useful theoretical scheme comes along and supplants it. Is there really a limbic system? This is an unanswer-able question. There is no external 'realness' about theories. Scientific reality, such as it is, changes with the times and with the ever-greater accumulation of information. After discussing the various levels at which common objects, such as 'wood' and 'table' can be described ranging from every day language to conceptualization at the level of molecules and the groupings of atoms, Conant goes on to say, "...the question of the reality of many of the conceptual schemes of the scientist pose no more difficult problem than the question of the reality of the common sense concept of a table or the material we call wood. For scientists as for laymen, when they are not on their guard the degree of reality is largely a function of the degree of familiarity with the concept or conceptual scheme; this in turn is a function of the fruitfulness of the idea over a considerable period of time." (Conant, pp. 35-36) The reason that the 'limbic system' is so frequently used is that it has been a useful, even fruitful concept, over a period of many years. Most people understand it in a general way. Someday, it will likely be replaced by one or more concepts that are more fruitful and which 'fit in' with more adequate theories about other brain systems. But, until this occurs, the limbic system will remain with us. In the quotation from Dr. Conant, it should be noted that he believes scientific reality can exist 'in degrees.' In the world of theory, things can be more or less real. The idea that concepts and ideas, simple or complex, can be more or less 'real,' foreshadows the approach taken by mathmeticians and logicians, not …