Examples of Definition Failure

 Plato talked about forms. He was confused. The literature contains cogent refutations from such luminaries as plato.
 What you want are definitions. Reality is too big to grasp directly. We are small and have small cognitive hands. Hence we bolt handles onto Reality and grasp those instead. The first handle is arbitrary, but after that there's right ways and wrong ways to bolt handles in relation to each other.

 Example:
 If you try to define [life] physically, you will find either nothing is alive or everything is alive. You can still make a semi-functional  handle, but you have to throw down arbitrary cutoffs. [Life is what we define as alive.]
 Life has goals. It has some outcome it will try to secure. This immediately goes recursive; life tries to stay alive. If it loses the ability to strategically direct energy, it will lose the ability to pursue any goal. This is a definition that doesn't converge. You can't define things in terms of themselves.
 [Life is something you can kill.] You can stab it and it stops moving. Machines are alive...

 You have control of actions, but not consequences. You can define things any way you want, it's fine. You can't control what the consequences of the definition are. You have to decide on an action, or definition, based on its immutable consequences.

 Alt: you define life as [having consciousness], which is not a physical property. That's cool, that works, [life] is a scalar. Except, now, when you're sleeping, you're dead. You suicidal maniac, you kill yourself at least once a day. You enjoy it, you lunatic.

 Natural language works by arbitrary definition. You have a type specimen and a fuzziness quotient. A cat is defined by a platonic [form of the cat] except that platonic form is brain-specific. The fuzziness - how different something can be and still be a cat - is also arbitrary. These types of definitions are not logically useful. The form is hard to communicate. The form is an inaccurate recording of the specimen. Even if it wasn't inaccurate, the specimen has changed and therefore no physical object does or will match the definition. It's a quick and dirty pragmatism for the stupid.