Posted by alexandra_k on October 10, 2006, at 22:30:58
In reply to Re: experts say...ditch schizophrenia label » sleepygirl, posted by laima on October 10, 2006, at 22:00:43
Natural Kinds.
Water is H2O.
Turned out that all samples of water had an underlying essence in common and that essence was H2O. That means the term 'water' picks out an interesting category in nature. Because all samples of 'water' have an underlying essence in common you can make interesting generalisations about the behaviour of water. It is a scientifically useful category.
Greenstone is either Jadite or Nephrite.
Turned out that all samples of Greenstone don't have an underlying essence in common. Rather... There were two different things (with two different underlying essences) that fell under the concept 'greenstone'. So... Greenstone isn't a natural kind. Some samples of Greenstone are Jadite (with its underlying essence) and some samples of Greenstone are Nephrite (with its underlying essence). There aren't very many scientifically interesting generalisations you can make about Greenstone because Greenstone isn't a natural kind. We say that the term 'Greenstone' has 'split reference'.
We could of course have decided that Jadite was the essential nature of Greenstone and we were simply wrong in considering Nephrite to be Greenstone. It would seem to be an arbitrary decision to consider Jadite to be the essence rather than Nephrite, however. Another thing we could say is that Greenstone has the following disjunctive essence in common: 'Greenstone' is 'either Jadite OR Nephrite'. One could do this... But the trouble is that Jadite behaves interestingly differently from Nephrite so to classify the essence of Greenstone as disjunctive is an impediment to the progress of science.
Ditto with the majority of psychiatric categories...
No underlying essences in common...
Our categories are more like 'Greenstone' than 'H2O'.
So...
Better categories are needed.I'm a fan of the symptom approach.
Trouble is that the same issue arises on the level of symptoms...
It seems likely that delusions that arise in response to cerebral injury are importantly different from delusions that arise in a context of psychosis, for example. Well... That is okay. Methinks the DSM should be working to classify symptoms on the basis of cause (aetiology) anyways. Clades have worked out pretty well for Biology (for example)...
poster:alexandra_k
thread:693568
URL: http://www.dr-bob.org/babble/20061003/msgs/693719.html