Editing Cognitive categorization (section)

===Conceptual clustering===
{{main|Conceptual clustering}}
'''Conceptual clustering''' is a [[machine learning]] paradigm for [[unsupervised classification]] that was defined by [[Ryszard S. Michalski]] in 1980.<ref>{{cite journal
  | author = Fisher, Douglas H.
  | year = 1987
  | title = Knowledge acquisition via incremental conceptual clustering
  | journal = Machine Learning
  | volume = 2
  | pages = 139–172
  | doi = 10.1007/BF00114265
  | issue = 2| doi-access = free
  }}
</ref><ref>{{cite journal
  | author = Michalski, R. S.
  | year = 1980
  | title = Knowledge acquisition through conceptual clustering: A theoretical framework and an algorithm for partitioning data into conjunctive concepts
  | journal = International Journal of Policy Analysis and Information Systems
  | volume = 4
  | pages = 219–244}}</ref> It is a modern variation of the classical approach of categorization, and derives from attempts to explain how knowledge is represented. In this approach, [[Class (philosophy)|classes]] (clusters or entities) are generated by first formulating their conceptual descriptions and then classifying the entities according to the descriptions.<ref>{{Citation |last=Kaufman |first=Kenneth A. |title=Conceptual Clustering |date=2012 |url=http://link.springer.com/10.1007/978-1-4419-1428-6_1219 |encyclopedia=Encyclopedia of the Sciences of Learning |pages=738–740 |editor-last=Seel |editor-first=Norbert M. |place=Boston, MA |publisher=Springer US |doi=10.1007/978-1-4419-1428-6_1219 |isbn=978-1-4419-1427-9}}</ref>

Conceptual clustering developed mainly during the 1980s, as a [[machine learning|machine]] paradigm for [[unsupervised learning]]. It is distinguished from ordinary [[Cluster analysis|data clustering]] by generating a concept description for each generated category.

Conceptual clustering is closely related to [[fuzzy set]] theory, in which objects may belong to one or more groups, in varying degrees of fitness. A [[cognition|cognitive]] approach accepts that natural categories are graded (they tend to be [[fuzzy concept|fuzzy]] at their boundaries) and inconsistent in the status of their constituent members. The idea of necessary and sufficient conditions is almost never met in categories of naturally occurring things.