If you can’t define something you have no formal rational way of knowing that it exists. Neither can you really tell anyone else what it is. There is, in fact, no formal difference between inability to define and stupidity.

Definitions are the foundation of reason. You can’t reason without them.

99 per cent of your life recognises things without definition, a baby recognises its mother's face without having it defined. It's just an arbitrary rule this rule of definition that Socrates set down.

Definitions are the foundation of reason. You can't reason without them.