Published online by Cambridge University Press: 14 August 2009
Personality disorders, severe and otherwise, constitute what one might call afuzzy set, after the theory developed by Lotfi Zadeh (1987), and expanded by Bart Kosko (1993). An analogous concept is that of “warmth” as applied to the ambient temperature: there are numbers below which almost no one would consider the temperature “warm,” and other readings, say – above 122 °F/50 °C – that would almost universally be experienced astoo warm. As the temperature approached 50 °C, gradually increasing percentages of people would conclude it was “too hot.” This gradual change, which would speed up as one got very near to 50 °C, is the fuzzy set. As Kosko points out, the termlife is itself fuzzy (p. 242). When it begins (when the sperm meets the egg? at the blastula stage? later?) is a matter of shading; a matter of degree and debate. Questions concerning fuzzy sets are decided often by expert opinion, not precise scientific measurement. In the domain of medical diagnosis, models that use cluster analysis may begin with performing a clustering algorithm on a set of patients – “by examining (a) the similarity of the presence and (b) the severity of symptom patterns exhibited by each” (Klir and Folger, 1988, p. 252). The authors mention that the similarity measure is usually computed between the symptoms of the patient in question and the symptoms of a patient possessing (by experts' agreement) the prototypical symptom pattern for each possible disease or condition.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.