In any good and strong argument, we need to always AVOID having Vagueness in our premise and conclusion whereby the message sent to the other party should be Clear and Complete.

For example :-

A police officer asked an eyewitness: "Since you witnessed the robbery and you saw the robber face to face, could you please describe him for me?"

 

The eyewitness replied: "Well, he was quite tall, kinda short and, you know, dark but not too dark skinned - Let me think, and errrr, He was a person."

What the....??? The eyewitness is clearly missing the STANDARD here...