Necessary and sufficient conditions

One of approaches which used to describe concepts is necessary and sufficient condition. We have to add some necessary information and conditions if we want to define something using this approach. The information can be organized by making a list of characteristics or attributes.

Example:

·         Cake                (a) sweet

                                    (b) round shape

                                    (c) big

·         Paper               (a) thin

(b) square shape

(c) made of pulp

            One major problem with this approach is that it is difficult to make a set of characteristics or attributes. Speakers and listeners have to share the same information to get to the concept. Actually, it’s hard even for nouns which identify concrete and natural kinds like horse. 

            Example:

·         Zebra               (a) an animal

(b) has four legs

(c) herbivore

(d) striped

            The problems are what if a three-legged zebra comes into the world, it’ll still zebra and what if we find no stripe in zebra, we still call it zebra. It’s problematic to cover this unpredictable condition.

Reference

Saeed, John I. 2003. Semantics. UK: Blackwell Publishing