Necessary & Sufficient Conditions + Wittgenstein's Objection

Philosophers analyze concepts. One way to do that is to give the necessary and sufficient conditions for the concept. This video explains the difference between necessary conditions and sufficient conditions. It also describes how these get used in philosophical analysis, and Wittgenstien's objection to such methods.

Intro: (0:00)
Necessary Conditions: (0:33)
Sufficient Conditions: (1:33)
How They Relate: (2:20)
Philosophical Analysis: (2:57)
Conclusion: (4:58)

[ThinkingAboutStuff]

So, can you define "chair"? What are its necessary and sufficient conditions?

[LetsGetLogical]

To be a chair it is necessary and sufficient to be an instantiation of _chair-ness_ .