Classification

Classification is the distinction, identification, and organization of two or more items, information and facts according to similarities which are determined through comparison.

Definition According to Gottfried Wilhelm von Leibniz:

Definition is the differentiation of two or more objects which is not exactly alike essential dissimilarity.Gottfried Wilhelm von Leibniz

Plato's Theories of Universals:

• Universalia in re (Universal in things)

Everything is combination of form and matter.

• Universalia ante rem (Universal before the thing)

The link between the members of the class is that they are all imitation of an archetype which existed befor the world has made.

• Universalia post rem (Universal after the thing)

Nothing general exists, only particulars.
Plato

Four different types of similarities in descending order of usefulnes for purposes of identification:

• Genetic similarities- similar origins.
• Structural similarities- same constituent in parts.
• Functional similarites- similar behavior.
• Apparent similarities- same physical features.